The Elements (Oxford Chemistry Guides) [3 ed.] 019855818X

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C0

Sr

Nb

73

Ta

72

71

i

H n * M )/kJ mol1: n.a. Ionization energies/'kj mol ‘:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M+ M2+ M3* M4* M5* M6+ M7* M8" M9+

-> —> -> -4 —>

—> —> -A

499 MT 1170 M2* 1900 M3+ (4700) M4* (6000) M5+ (7300) M6+ (9200) M7* M8+ (10 500) M9+ (11900) M10+ (15 800)

Electron binding energies /eV

K L,

Ln Lm M, M„

Mp, Mw Mv

Is 2s 2Pt/2 2p3/2 3s 3Pl/2 3P3/2 3d3/2 3d5/2

106 755 19 840 19 083 15 871 5002 4656 3909 3370 3219

Main lines in atomic spectrum

[Wavelength/nm(species)] 386.312 (II) 408.844 (II) 416.840 (II) 438.641 (II) 450.720 (ID 591.085 (II)

continued in Appendix 2, p255

•CRYSTAL Crystal structure (cell dimensions/pm), space group

f.c.c. {a = 531.1), Fm3m X-ray diffraction: mass absorption coefficients (p/p)/cm2 g ': CuKa n.a.

MoKa n.a.

Neutron scattering length, bl 10~12 cm: n.a. Thermal neutron capture cross-section, M )/kJ mol'1: 44 Ionization energies/kj mol'1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M4 M24 M3+ M4+ M5+ M64 M7* M8* M;l+

-» M4 -> M2+ -+ M34 M44 -> M54 -> M64 -+ M7+ -» M84 -> M9+ -+ M'“4

577.4 1816.6 2744.6 11575 14 839 18376 23 293 27457 31857 38 459

•CRYSTAL

Electron binding energies /eV

Lu

Is 2s 2pi,2

L[u

2P3/2

K L,

1559.0 117.8 72.9 72.5

Main lines in atomic spectrum

[Wavelength/nm(species)] 308.215 0) 309.271 (I) (AA) 309.281 (I) (AA) 394.401 (I) 396.152 (I)

DATA

Crystal structure (cell dimensions/pm), space group

f.c.c. [a = 404.959), Fm3m X-ray diffraction: mass absorption coefficients {p/p) Icm2 g ': CuKa 48.6 MoKa 5.16 Neutron scattering length, bt 10'12 cm: 0.3449 Thermal neutron capture cross-section, M“)/kJ mol"1: n.a. Ionization energies/kj mol1:

1. M

-» M+

578.2

•CRYSTAL

Electron binding energies/eV

Main lines in atomic spectrum

n.a.

[Wavelength/nm(species)I 367.312 (I) 377.750 (II) 392.625 (ID 408.929 (II) 428.926 (D 450.945 (II) 457.559 (II) 466.279 (ID 605.464 (I)

DATA

Crystal structure (cell dimensions/pm), space group

ct-Am h.c.p. (a = 346.80, c= 1124.0), P63/mmc P-Am f.c.c. (a = 489.4), Fm3m T{a -> p) = 1347 K X-ray diffraction: mass absorption coefficients (p/p)/cm2 g"1: CuKa n.a. MoKa n.a. Neutron scattering length, b/10"12 cm: 0.83 Thermal neutron capture cross-section, cr, I barns: 75.3 (243Am)

•GEOLOGICAL

DATA

Minerals None. Chief source: 243Am is produced in 100 g

Abundances

quantities by neutron bombardment of 239Pu, and has a relatively long half-life. Although 24IAm has a shorter half-life, it can be extracted from 241Pu that has been subjected to neutron bombardment over a period of years.

Sun (relative to H = 1 x 1012): n.a. Earth’s crust/p.p.m.: nil Seawater/p.p.m.: nil

World production: n.a. but probably a few kgs per

year. Specimen: 241Am and 243Am are commercially

available, under licence - see Key.

21

Sb

Atomic number: 51 Relative atomic mass (,2C = 12.0000): 112.760

CAS: [7440-36-01

•CHEMICAL Description: Antimony is a metalloid element with three forms. The metallic form is the

more stable and is bright, silvery, hard and brittle. It is stable in dry air, and is not attacked by dilute acids or alkalis. The addition of antimony will harden other metals, and it is used in storage batteries, bearings, etc. Radii/pm: Sb5+ 62; Sb3t 89; Sir 245; atomic 182; covalent 141; van der Waals 220 Electronegativity: 2.05 (Pauling); 1.82 (Allred); 4.85 eV (absolute) Effective nuclear charge: 6.30 (Slater); 9.99 (Clementi); 12.37 (Froese-Fischer)

Standard reduction potentials ZT7V V acid

Sb205

IV

-III

III

0.605

0.204

SbO+ -

Sb205-^ Sb204-^ Sb406 ■

neutral

I

Sb

0.150

-0.510

Sb-

0.699 -1.338

base

[Sb(OH)g]~

-[Sb(OH4r

Oxidation states Sb-"' Sbm

[Xe] s2

Sbv

d10

SbH3

Sb

SbH.

Covalent bonds

SbH3 Sb406, Sb033- (aq), SbF3, SbCl3 etc., [SbFJ2-, Sb2S3 SbAo, [SbfOHJJ- (aq), SbF5, SbCl5 etc., [SbCl6]“, [SbBr6]"

r / pm 171 220 200 203 233 290

Bond Sb—H Sb—C Sb—O Sb—F Sb—Cl Sb—Sb

El kj mol 1 257 215 314 440 316 295

•PHYSICAL Melting point/K: 903.89

Afffusi^/kJ mob1: 20.9

Boiling point /K: 1908

Thermodynamic properties (298.15 K, o.i MPa) State Solid Gas

A,H®/kJ mol1 0 262.3

AfG®/kJ mol'1 0 222.1

S*/J KP1 mol'1 45.69 180.27

C„/J K1 moP1 25.23 20.79

Density/kg m'3: 6691 [293 K]; 6 483 [liquid at m.p.]

Young’s modulus/GPa: 54.7

Molar volume/cm3: 18.20

Rigidity modulus/GPa: 20.7

Thermal conductivity/W m 1 K ‘: 24.3 [300 K] Coefficient of linear thermal expansion/K_1: 8.5 x 10 6 Electrical resistivity In m: 39.0 x 10-8 [273 K] Mass magnetic susceptibility/kg 1 m3:-1.0x 10"8 (s)

Bulk modulus/GPa: n.a.

•BIOLOGICAL

Poisson’s ratio/GPa: 0.25 - 0.33

DATA

Biological role

Levels in humans

None.

Blood/mg

Toxicity

Bone/p.p.m.:

Toxic intake: 100 mg Lethal intake: antimony provokes vomiting,

and was once prescribed for this purpose, but medical dose is near to toxic dose and antimony can kill. LD50 (oral) for antimony potassium tartrate is c. 140 mg.

Hazards Small doses of antimony stimulate metabolism, large doses cause liver damage. 22

dm"3:0.0033 0.01 - 0.6 Liver/p.p.m.: 0.011-0.42 Muscle/p.p.m.: 0.042 - 0.191 Daily dietary intake: 0.002 - 1.3 mg Total mass of element in average (70 kg) person:

2 mg

Probably known to the ancients and certainly to the alchemists.

Antimony

[Greek, anti + monos = not alone; I.atin, stibium| French, antimoine; German, Antimon; Italian, antimonio-, Spanish, antimonio

[anti-moni]

•NUCLEAR Isotope mass range: 108 —> 136

Number of isotopes (including nuclear isomers): 40

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spill I

120.9038212 5/2+ 57.3 ,2,Sb 122.904 2160 42.7 7/2+ ,23Sb A table of radioactive isotopes is given in Appendix 1, on p235.

l21Sb 0.16 520 6.4016 xlO7 -0.360 x 10-28 23.930

NMR [Reference: [N(C2H5)4][SbCl6]] Relative sensitivity ('H = 1.00) Receptivity (l3C = 1.00) Magnetogyric ratio/rad T ‘s ' Nuclear quadrupole moment/m2 Frequency (*H = 100 Hz; 2.3488T)/MHz

•ELECTRON

Nuclear magnetic Uses moment p +3.3634

E, NMR

+2.5498

E, NMR

123Sb 4.57 x 10-2 111 3.4668 x 107 -0.490 x 10-28 12.959

SHELL

Ground state electron configuration: [Kr]4d105s25p3 Term symbol: 4S3/2 Electron affinity (M -> M-)/kJ mob1: 101 Ionization energies/kj mol-1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M4 M24 M3+ M4* M54 M6* M74 M84 M94

—> M+ -> M2+ M3t -> M4+ -> M5* M6+ M74 —> M8+ -> M9+ —> M104

•CRYSTAL

Main lines in atomic spectrum

Electron binding energies/eV

833.7 1794 2443 4260 5400 10400 (12 700) (15200) (17 800) (20400)

K L, Ln Lm M, Mn Mra M„ Mv

Is 2s 2pi/2 2p3/2 3s 3pt« 3p3/2 3dj/2 3d5/2

[Wavelength/ nm(species) ] 206.833 (I) (AA) 217.581 (I) 231.147 (I) 252.852 (I) 259.805 (I)

30 491 4698 4380 4132 946 812.7 766.4 537.5 528.2

continued in Appendix 2, p255

DATA

Crystal structure (cell dimensions/pm), space group

grey rhombohedral (a = 430.84, c = 1124.7), R3m (grey) cubic (a = 298.6), Pm3m metal h.c.p. [a - 336.9, c= 533), P63/mmc X-ray diffraction: mass absorption coefficients (p/p)/cm2 g-1: CuKa 270 MoKa 33.1 Neutron scattering length, bl 10-12 cm: 0.557 Thermal neutron capture cross-section, a,/barns:4.91

GEOLOGICAL Minerals A little native antimony occurs naturally as granular masses or nodules, generally in silver-bearing lodes, and has been found in Sweden, Germany, Italy, and the USA. Mineral Sibiconite Stibnite Tetrahedrite Ullmannite

Formula Sb306(OH) Sb2S3 (Cu,Fe)i2Sb4S13 NiSbS

Density 5.58 4.63 4.97 6.65

Hardness 4-5.5 2 3-4.5 5 - 5.5

Crystal appearance hex., res./adam. black hex., yellow, tiny prisms rhom., adam. white/brown cub., metallic grey

Chief ores: stibnite. Tetrahedrite, although

Abundances

mainly a copper ore, yields antimony as a by-product.

Sun (relative to H = 1 x 1012): 10

World production /tonnes y-1:53 000 Main mining areas: China, Italy, Peru, Mexico,

Bolivia, France.

Earth’s crust/p.p.m.: 0.2 Seawater/p.p.m.: c. 3 x 10 4 Residence time/years: c. 3.5 x 105 Classification: accumulating Oxidation state: III

Reserves/tonnes: 2.5 x 106 Specimen: available as pieces, powder or shot.

Care!

23

Ar

Atomic number: 18 Relative atomic mass (12C = 12.0000): 39.948

CAS: [7440-37-1]

•CHEMICAL Discovery: Argon was discovered in 1894 by Lord Rayleigh (London) and Sir William

Ramsay (Bristol), England. Description: Argon is a colourless, odourless gas comprising 1% of the atmosphere, from which it is extracted after liquefaction. Argon is inert towards all other elements and chemicals. It is used as an inert atmosphere in lamps and high temperature metallurgy. Radii/pm: atomic 174; van der Waals 191 Electronegativity: n.a. (Pauling); 3.20 (Allred); [7.70 eV (absolute) - see Key] Effective nuclear charge: 6.75 (Slater); 6.76 (Clementi); 7.52 (Froese-Fischer)

Oxidation states Ar°

[Ar]

Ar8(H20)46 and Ar(quinol)3. These are not true compounds but clathrates in which argon atoms are trapped inside a lattice of other molecules.

•PHYSICAL

DATA

Melting point/K: 83.78

A/ff^/kJ mol-1: 1.21 Af/vap/kJ mol-1: 6.53

Boiling point/K: 87.29 Critical temperature/K: 150.87 Critical pressure/ kPa: 4862

Thermodynamic properties (298.15 K, o.l MPa) State Gas

Aff/ M3+ 4837 —> M4+ 6042 -V M5" 12305 -> M6+ M7+ (15 400) (18 900) —> M8* (22 600) -> M9+ (26 400) —» Ml0+ —>

Electron binding energies/eV

Is 2s 2pi/2 2ps/2 3s 3pi/2

K L,

Lu Lin M, M„ Mln

11867 1527.0 1359.1 1323.6 204.7 146.2 141.2 41.7 41.7

3P:j/2

3d3/2 3d5/2

M,v Mv

Main lines in atomic spectrum

[Wavelength/nm(species)l 193.759 (I) (AA) 419.008 (II) 445.847 (II) 446.635 (II) 449.423 (II) 450.766 (II) 454.348 (II)

•CRYSTAL Crystal structure (cell dimensions/pm), space group

a-As rhombohedral (a = 413.18, a = 54° 10'), R3m, metallic form P-As hexagonal [a = 376.0, c= 10.548), yellow grey amorphous T{a -+ /I) = 501 K; T(p -> grey) = room temperature X-ray diffraction: mass absorption coefficients (/i/p)/cm2 g ': CuKa 83.4 MoKa 69.7 Neutron scattering length, b/10-12 cm: 0.658 Thermal neutron capture cross-section, M )/kJ mol1: -46 Ionization energies/k] mol':

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M+ M2+ M3* M4* M5t M6t M7t M8+ M9+

-> M* M2+ -> M3* M4+ ^ M5t -> -> M7+

502.8 965.1 (3600) (4700) (6000) (7700) (9000) (10 200) -+ M9t (13 500) M10* (15 100)

•CRYSTAL

Main lines in atomic spectrum

Electron binding energies / eV

Is 2s

K Li Ln H,I M, M„ Mra Mw Mv

37 441 5989 5624 5247 1293 1137 1063 795.7 780.5

2pI/2

2p3/2

3s 3Pl/2 3P3/2

3d3/2 3d5/2

[Wavelength/nmfspecies)] 350.111 (I) 455.403 (II)

493.409 (II) 553.548 (II) (AA) 614.172 (II) 649.690 (II) 705.994 (I)

continued in Appendix 2, p255

DATA

Crystal structure (cell dimensions/pm), space group

b.c.c. (a = 502.5), Im3m high pressure form: [a = 390.1, c-615.5), P63/mmc X-ray diffraction: mass absorption coefficients (p/p)/cm2 g”1: CuK„ 330 MoKa 43.5 Neutron scattering length, h/1012 cm: 0.507 Thermal neutron capture cross-section, +,/barns: 1.3

•GEOLOGICAL Minerals Mineral Barite Benitoite* Witherite

Formula BaS04 BaTiSi-A, BaCO,

Density 4.50 3.6 4.219

Hardness 3-3.5 6.3 3-3.5

Crystal appearance orth., vitr./res. colourless-yellow hex. trans. blue orth., vitr./res. colourless/grey

‘gemstone Chief ores: barite mainly, witherite occasionally World production/tonnes y"1: 6 x 106 (barium ores) Main mining areas: UK, Italy, Czech Republic

(Pribram), USA, Germany. Reserves/tonnes: 450x10® Specimen: available as granules, rods or stick,

Warning!

Abundances Sun (relative to H = 1 x 1012): 123 Earth's crust/p.p.m.: 500 Seawater/p. p.m.:

Atlantic surface: 4.7 x 10'3 Atlantic deep: 9.3 x 101 Pacific surface: 4.7 x 10 3 Pacific deep: 20.0 x 10 3 Residence time/years: 10 000 Classification: recycled Oxidation state: II

31

Bk

Atomic number: 97 Relative atomic mass (lzC = 12.0000): 247.0703 (Bk-247)

•CHEMICAL

CAS: [7440-40-6]

DATA

Description: Berkelium is a silvery, radioactive metal. It is attacked by oxygen, steam and

acids, but not alkalis. Radii/pm: Bk4’ 87; Bk3* 98; Bk2+ 118; atomic 170 Electronegativity: 1.3 (Pauling); 1.2 (est.) (Allred); n.a. (absolute) Effective nuclear charge: 1.65 (Slater)

Standard reduction potentials E /V IV

III

II -1.96

acid

Bk4+

-2.80

•>.

-1.54

+l'6? Bk3+ - (Bk^- Bk

Oxidation states Bk" P Bk"1 f Bkw

f

BkO Bk203, BkF3, BkCL, etc., [BkCI6]3-, Bk3+ (aq), [Bk(C5H5)3] Bk02, BkF„

• P H Y S I C A L

DATA

Melting point/K: 1320

AW^/kJ mol‘: n.a. A//yap/kJ mol‘: 310

Boiling point/K: n.a.

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

AfFf’VkJ mol'1 0 n.a.

AfGe/kJ mol-1 0 n.a.

S«/J K1 mol1 n.a. n.a.

(yj K 1 mol-' n.a. n.a.

Density/kg m“3: 14 790 [293 K]

Young’s modulus/GPa: n.a.

Molar volume/cm3: 16.70

Rigidity modulus/GPa: n.a.

Thermal conductivity/W rn1 K 1: 10 (est.) [300 K]

Bulk modulus/GPa: n.a.

Coefficient of linear thermal expansion /K'1: n.a. Electrical resistivity/n m: n.a.

Poisson’s ratio/GPa: n.a.

Mass magnetic susceptibility/kg 1 m3: n.a.

•BIOLOGICAL

A T A

Biological role

Levels in humans

None.

nil

Toxicity Toxic intake: n.a. Lethal intake: n.a.

Hazards Berkelium is never encountered normally. It is dangerous because it is a powerful source of radiation and the maximum body burden is 0.0004 pCi. This element is only to be found inside nuclear facilities or research laboratories.

32

Daily dietary intake:

nil

Total mass of element in average (70 kg) person:

nil

Discovery: see Nuclear Data section. (Named after Berkeley]

BCrRCIIUIII

French, berkelium; German, Berkelium; Italian, berkelio; Spanish, berkelio

•NUCLEAR

[berk-eel-iuhm]

DATA

Discovery: Berkelium was first produced in 1949 by S.G. Thompson, A. Ghiorso, and

G.T. Seaborg at Berkeley, California, USA. Number of isotopes (including nuclear isomers): 15

Isotope mass range: 240 -> 251

Key isotopes Nuclide

Atomic mass

Half life (T1;2) Decay mode and energy (MeV)

2«Bk

243.062997

4.5 h

EC (1.505) 99.8%; a (6.871) 0.2%; y

3/2-

244Bk

244.065 160

4.4 h

EC (2.25) 99.99%; a (6.778) 0.01%; y

4-

245Bk

245.066357

4.94 d

EC (0.812) 99.9%; a (6.453) 0.1%; y

3/2-

2,6Bk

246.068720

1.80 d

EC (1.5);-y

2-

247Bk

247.070300

1400 y

a (5.889); y

3/2-

2,|8Bk

248.073 106

23.7 h

P- (0.87); 70%; EC (0.72) 30%; y

1-

249Bk

249.074980

320 d

P- (0.125); a (5.525) 0.001%

7/2+

““Bk

250.078312

3.217 h

P-(1.781); y

2-

Nuclear Nucl. mag. Uses spin / moment g

2.0

R

Other isotopes of berkelium have half lives less than 1 h.

NMR (not recorded]

ELECTRON

SHELL

Ground state electron configuration: [Rn]5f97s2 Term symbol: 6H15/2 Electron affinity (M -* M')/kJ mol-1: n.a. Ionization energies/kj mol ‘:

1. M

-+ M+

•CRYSTAL

601

Electron binding energies /eV

Main lines in atomic spectrum*

n.a.

[Wavelength/nm(species)j 323.972 5) 325.219 (I) 328.875 (I) 328.935 d) 333.526 ffl 340.828 ffl 342.695 3) *first seven lines associated with the neutral atom

DATA

Crystal structure (cell dimensions/pm), space group

a-Bk h.c.p. /3-Bk f.c.c. T(a ~^0) = 1203 K X-ray diffraction: mass absorption coefficients (/i/p)/cm2 g 1: CuKa n.a. MoKa n.a. Neutron scattering length, fe/10-12 cm: n.a. Thermal neutron capture cross-section, 215

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin /

Nuclear magnetic Uses moment p

209Bi

208,980374

100

9/2-

+4.1106

NMR

A table of radioactive isotopes is given in Appendix 1, on p236.

NMR [Reference: KBiF6]

2°9Bi

Relative sensitivity ('H = 1.00)

0.13 777 4.2986 x 107 -0.500 x 10'28 16.069

Receptivity (13C = 1.00) Magnetogyric ratio/rad "T's-1 Nuclear quadrupole moment/m2 Frequency (‘H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

Ground state electron configuration: [Xe]4fI45d'°6s26p3 Term symbol: 4S3;2 Electron affinity (M -> M )/kJ mol-1: 91.3 Electron binding energies /eV

Ionization energies/kj mol 1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M+ M24 M3+ M4+ M5+ M6+ M7+ M8+ M94

-> -» •> -+ -> -> -> -+ ++ ->

M4 M2+ M3+ M4+ M5t M6+ M7+ M8+ M9+ M104

703.2 1610 2466 4372 5400 8520 (10 300) (12300) (14300) (16 300)

•CRYSTAL

K Li Ln Lin

Mi M„ M,„ Mjv

Mv

Is 2s 2pi/2 2p3/2 3s

Main lines in atomic spectrum

[Wavelength / nm(species) ] 202.121 (I) 206.170 (I) 211.026(1) 223.061 (I) (AA) 289.798 (I) 306.772 (I)

90 526 16388 15711 13419 3999 3696 3177 2688 2580

3Pl/2 3p3/2

3d3/2 3d5;2

continued in Appendix 2, p255

DATA

Crystal structure (cell dimensions/pm), space group

rhombohedral (a = 454.950, c- 1186.225), R3m X-ray diffraction: mass absorption coefficients (p/p) I cm2 g'1: CuKa 240 MoKa 120 Neutron scattering length, bl 10'12 cm: 0.8533 Thermal neutron capture cross-section, 262

Key isotopes Nuclide

26lBh 262Bh 262mBh

Atomic mass

261.127 262.1231

Half life (T„2) Decay mode and energy (MeV)

0.012 s 0.1s 8x 10~3s

Nuclear Nucl. mag. Uses spin I moment [i

ot; SF a a

NMR [Not recorded)

•ELECTRON

SHELL

Ground state electron configuration: [Rn]5f"6d57s2 Term symbol: 6S5/2 Electron affinity (M -> M')/kJ mol"1: n.a. Ionization energies/kj mol'1:

1. M

-> M*

660 (est.)

•CRYSTAL

Electron binding energies/eV

Main lines in atomic spectrum

n.a.

[Wavelength/nm(species)] n.a.

DATA

Crystal structure (cell dimensions/pm), space group

n.a. X-ray diffraction: mass absorption coefficients (p/p)/cm2 g"1: CuKa n.a. MoKa n.a. Neutron scattering length, bl 10 n cm: n.a. Thermal neutron capture cross-section, a,I barns: n.a.

•GEOLOGICAL

DATA

Minerals Not found on Earth.

bohrium was made by the so-called cold fusion method in which a target of bismuth was bombarded with atoms of chromium having just the right energy to cause fusion. An atom of bohrium was detected:

Chief source:

Abundances Sun (relative to H = 1 x 1012}: n.a. Earth’s crust/p.p.m.: nil Seawater/p.p.m.: nil

209Bi + MCr -> 262Bh + n Specimen: not available commercially.

39

Atomic number: 5 Relative atomic mass (l2C = 12.0000): 10.811

CAS: [7440-42-8]

•CHEMICAL Discovery: Boron was discovered in 1808 by L.J. Lussac and L.J. Thenard in Paris, France and

Sir Humphry Davy in London, England. Description: Boron is a non-metal element with several forms - the most common is amorphous boron, which is a dark powder, unreactive to oxygen, water, acids and alkalis. It reacts with metals to form borides. Boron compounds are used in borosilicate glass, detergents and fire-retardants. Radii /pm: B3+ 23; atomic 83; covalent

; van der Waals 208

88

Electronegativity: 2.04 (Pauling); 2.01 (Allred); 4.29 eV (absolute) Effective nuclear charge: 2.60 (Slater); 2.42 (Clementi); 2.27 (Froese-Fischer)

Standard reduction potentials E^IV

in B(OH)3

o -°'890

B

BF4~ —B

Oxidation states

Covalent bonds

Bm

Bond B—H B—H—B B—C B—O B—F B—Cl B—Br B—B

[He]

B203, H3BO3 (= B(OH)3), borates e.g. borax Na2[B405(0H)4].8H20, B2H6, B4H10 etc., NaBH4, BF3, BC13 etc.

•PHYSICAL

r/ pm 119 132 156 136 129 175 187 175

El kj m 381 439 372 536 613 456 410 293

DATA

Melting point/K: 2573

A/f^/kJ moP1: 22.2 Atfvap/kJ moL1: 538.9

Boiling point/K: 3931

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid (a) Gas

AfFP/kJ mol ' 0 562.7

AtG M")/kJ mol’1: 26.7 Ionization energies/kj mol’1:

1. 2. 3. 4. 5.

M M* M2+ M3* M“+

-> -+ .■+ -+ -+

M+ M2+ M3+ M4+ M5+

•CRYSTAL

800.6 2427 3660 25 025 32 822

Electron binding energies/eV

K

Is

Main lines in atomic spectrum

[Wavelength/nm(species)[ 208.891 (I) 208.957 (I) 249.667 (I) 249.773 (I) (AA) 345.129 (I) 1166.004(1) 1166.247(1)

188

DATA

Crystal structure (cell dimensions/pm), space group

Tetragonal (a= 874.0; c= 506), P42/nnm a-B rhombohedral (a = 506.7, a = 58° 4'), R3m /3-B rhombohedral (a - 1014.5, a= 65° 12'), R3m, R32, R3m Orthorhombic {a = 1015, b = 895, c = 1790) Monoclinic (a = 1013, b = 893, c = 1786, a ~ 90°, /3 == 90°, y~ 90°) or triclinic Hexagonal (a= 1198, c= 954) X-ray diffraction: mass absorption coefficients (|t/p)/cm2 g’1: CuKu 2.39 MoKI( 0.392 Neutron scattering length, b/10’12 cm: 0.535 Thermal neutron capture cross-section, -ra/barns: 767

•GEOLOGICAL Minerals Mineral Borax Colemanite Datolite Kernite Ulexite

Formula Na2BA(OH)„.8H20 CaB304(0H)3.H20 CaBSi04(OH) Na2B406.(0H)2.3H20 NaCaB506(0H)6.5H20

Density Hardness 1.715 2-2.5 2.423 4.5 3.0 5-5.5 1.908 2.5 1.955 2.5

Chief ores: kernite, borax, ulexite, colemanite World production/tonnes y-1:1 x 106 (B203) Main mining areas: ulexite in USA, Tibet, Chile;

colemanite in USA, Turkey Reserves/tonnes: 270 x 106 as B203 Specimen: available as crystals, pieces or powder. Safe.

Crystal appearance mon., vit./res./earthy colourless mon., vit./adam. colourless mon., vit. white mon., vit. colourless trie., silky/vit. colourless

Abundances Sun (relative to H = 1 x 1012): 2.63 x 105 Earth’s crust/p.p.m.: 950 Seawater/p.p.m.: 4.41 Residence time/years: 1 x 107 Classification: accumulating Oxidation state: III

41

Atomic number: 35 Relative atomic mass (12C = 12.0000): 79.904

•CHEMICAL

CAS: [7726-95-6]

DATA

Discovery: Bromine was discovered in 1826 by A.J.Balard at Montpellier, France, and C. Lowig

at Heidelberg, Germany. Description: Bromine is a red, dense, sharp-smelling liquid (Br2) that is extracted industrially from sea water. Bromine compounds are used in fuel additives, pesticides, flame-retardants and photography. Radii/pm: Br~ 196; covalent 114; van der Waals 195 Electronegativity: 2.96 (Pauling); 2.74 (Allred); 7.59 eV (absolute) Effective nuclear charge: 7.60 (Slater); 9.03 (Clementi); 10.89 (Froese-Fischer)

Standard reduction potentials E"7 V I

VII

0

-I

1.478 1.853

acid

1.447

1.604

1.0652

Br04 -Br03 -HBrO-Br2-Br 1.0874

Br2 (aq): 1.341 0.584 0.492

1.025

base

0.455

Br04 -BrOo -BrO -Br2

1.0652

Br¬

0.766

Oxidation states

Covalent bonds

Br 1 Br° Br1 BrUI Br™ Brv Br™

Bond Br—H Br—C Br—O Br—F Br—Cl Br—Br

[Kr] s2p5 s2p4 s2p2 s2p‘ s2 d10

Br (aq), HBr, KBr etc. Br2 Br20, BrCl2" BrF3, BrFp BrO, Br03- (aq), BrF5, BrF6~ KBr04, BrF,7

r/ pm 141 194 160 176 214 228

El kj mol

366 285 201 249 216 191

other bonds to bromine: see other elements

•PHYSICAL

DATA

Melting point/K: 265.9

AWfe^/kJ mol1: 10.8 AWvap/kJ mol-1: 30.0

Boiling point/K: 331.93 Critical temperature/K: 588

Thermodynamic properties (298.15 K, 0.1 MPa) State Liquid Gas (atom)

AfH®/kJ mol 1 0 111.884

AfG*/kJ moh' 0 82.396

SVJ K-1 mol 1

152.231 175.022

C„/J K-1 moP1 75.689 20.786

Density/kg m3: 4050 [123 K]; 3122.6 [293 K]; 7. 59 (gas) Molar volume/cm3: 19.73 [123 K] Thermal conductivity/W m 1 K 1: 0.122 [300 K] (1) Mass magnetic susceptibility/kg"1 m3: -4.44 x 10 9 (1)

m

•BIOLOGICAL

DATA

Biological role

Levels in humans

None proved.

Blood /mg dm 3:4.7 Bone/p.p.m.: 6.7 Liver/p.p.m.: 0.2 - 7 Muscle/p.p.m.: 7.7 Daily dietary intake: 0.8 - 24 mg

Toxicity Br2 is very toxic; bromide is slightly toxic. Toxic intake: 3 g (Br ) Lethal intake: LD50 (Br2, oral, human) = c. 1 g;

bromide > 35 g

Hazards Bromine is corrosive and its vapour attacks the eyes and lungs. Bromide intake leads to depression and loss of weight.

42

Total mass of element in average (70 kg) person:

260 mg

Discovery: see Chemical Data section.

Bromine

[Greek, bromos = stench] French, brome; German, Brom; Italian, bromo; Spanish, bromo

•NUCLEAR

;broh-meen]

DATA_

Number of isotopes (including nuclear isomers): 28

Isotope mass range: 72 -> 92

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin I

Nuclear magnetic Uses moment fi

7,Br

78.918336 1

50.69

3/2-

+2.106399

E, NMR

81Br

80.916289

49.31

3/2-

+2.270560

E, NMR

A table of radioactive isotopes is given in Appendix 1, on p237.

NMR [Reference: NaBr (aq)] Relative sensitivity ('H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T'1s"1 Nuclear quadrupole moment /m2 Frequency (‘H = 100 Hz; 2.3488T)/MHz

•ELECTRON

79Br 0.0786 226 6.7023 x 107 +0.331 xl0“28 25.053

81Br 0.0985 277 7.2246 xlO7 +0.276 x 10”28 27.006

mm

SHELL

Ground state electron configuration: [Ar]3dI04s24p5 Term symbol: 2P3/2 Electron affinity (M --> Mj/kJ mol-1: 324.7 Ionization energies /kj mol”1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M+ M2+ M3+ M4+ M5* M6* M7* M8+ M9+

1139.9 -» M+ 2104 M2+ 3500 —> M3+ 4560 -> M4" 5760 -» M5+ 8550 M6+ 9940 M7+ 18 600 -> M8+ -4 Ms+ (23 900) -4 M10+ (28 100)

Electron binding energies /eV

K L, Lu In. M, Mn Mm MIV Mv

Is 2s 2pm 2p3/2 3s 3Pi/2 3p3/2 3d3/2 3d5/2

Main lines in atomic spectrum

[Wavelength/nm(species)] 614.860 (I) 635.073 (I) 655.980 (I) 663.162(1) 751.296(1) 827.244 (I) 844.655 (I) 926.542 (I)

13474 1782 1596 1550 257 189 182 70 69

•CRYSTAL Crystal structure (cell dimensions/pm), space group

orthorhombic (120 K) (a = 673.7, b= 454.8, c= 876.1), Cmca X-ray diffraction: mass absorption coefficients (/i/p)/cm2 g l: CuK„ 99.6 MoKa 79.8 Neutron scattering length, fo/10 12 cm: 0.679 Thermal neutron capture cross-section, cra/barns: 6.8

•GEOLOGICAL

A T A

Minerals Mineral Bromargyrite

Formula AgBr

Density 6.474

Hardness 2.5

Crystal appearance res./adam. colourless

Chief source: : sea water, Dead Sea and natural

Abundances

brines; salt-lake evaporates

Sun (relative to H = 1 x 1012): n.a.

World production /tonnes y"1:330 000 Main mining areas: USA, Israel, UK, Russia, France,

Japan. Reserves/tonnes: almost unlimited

Earth’s crust/p.p.m.: 0.37 Seawater/p.p.m.: 65 Residence time/years: 1 x 108 Classification: accumulating Oxidation state: -I

Specimen: available as the liquid in sealed

ampoules. Danger!

43

Atomic number: 48 Relative atomic mass (12C = 12.0000): 112.411

•CHEMICAL

CAS: [7440-43-9]

A T A

Description: Cadmium is a silvery metal that tarnishes in air, and is soluble in acids but not

alkalis. It is used in rechargeable batteries, alloys and pigments, but because of its toxicity these uses are being phased out wherever possible. Radii/pm: Cd2* 103; Cd+ 114; atomic 149; covalent 141 Electronegativity: 1.69 (Pauling); 1.46 (Allred); 4.33 eV (absolute) Effective nuclear charge: 4.35 (Slater); 8.19 (Clementi); 11.58 (Froese-Fischer)

Standard reduction potentials E'7V II

0

acid

Cd2+ —

base

Cd(OH)2 — [Cd(NH3)4]2+ [Cd(CN)4]2- •

-0.4025 -0.824

-0.622 -1.09

- Cd - Cd - Cd - Cd

Oxidation states Cd1 Cd11

d'V d10

rare e.g. Cd2[AlCl4]2 CdO (basic), CdS, Cd(OH)2, CdF2, CdCl2 etc., many sits, [Cd(OH2)6]2+ (aq), many complexes, e.g. [Cd(SCN)4]2"

•PHYSICAL Melting point/K: 594.1

AW fusion/kj mol 1: 6.11

Boiling point/K: 1038

AWvap/kJ mol-1: 99.87

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

AtH*/kj mol’1 0 112.01

AfG *7kJ mol"1 0 77.41

Se/J K"1 mol"1 51.76 167.746

Cp/J K"1 mol"1 25.98 20.786

Density/kg m 3: 8650 [293 K]; 7996 [liquid at m.p.] Molar volume/cm3: 13.00

Young’s modulus/GPa: 62.6

Thermal conductivity/W m"1 K"1: 96.8 [300 K]

Bulk modulus/GPa: 51.0

Coefficient of linear thermal expansion/K"1:29.8 x 10"6

Poisson’s ratio/GPa: 0.30

Rigidity modulus/GPa: 24.0

Electrical resistivity/fi m: 6.83 x 10~8 [273 K] Mass magnetic susceptibility/kg 1 m3: -2.21 x 10~9 (s)

•BIOLOGICAL Biological role

Levels in humans

None has been proved, although suspected. It is stimulatory.

Blood/mg dm

Toxic intake: 17 mg kg"1 (chloride, oral, rat)

3:0.0052 1.8 Liver/p.p.m.: 2-22 Muscle/p.p.m.: 0.14 - 3.2 Daily dietary intake: 0.007 — 3

Lethal intake: LD50 (chloride, oral, guinea pig)

Total mass of element

= 63 mg kg"1

in average (70 kg) person:

Toxicity

Hazards Cadmium is toxic but its emetic action means that little is absorbed, so fatal poisoning rarely occurs. Cadmium is carcinogenic and teratogenic.

44

Bone/p. p.m.:

mg

50 mg

Discovered in 1817 by F. Stromeyer at Gottingen, Germany.

Cadmium

[Latin, cadmia = calamine] French, cadmium-, German, Kadmium; Italian, cadmio; Spanish, cadmio

[cad-mium]

•NUCLEAR Number of isotopes [including nuclear isomers): 31

Isotope mass range: 99 -> 124

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

106Cd

105.906461

1.25

Of

E

“Cd

107.904 176

0.89

Of

E

110Cd

109.903 005

12.49

Of

mCd

110.904 182

12.80

1/2+

,12Cd

111.902 757

24.13

0+

,1}Cd

112.904 400

12.22

1/2+

Nuclear spin /

Nuclear magnetic Uses moment p

E -0.594 885 7

E, NMR

-0.622 3005

E, NMR

E

113.903 357 28.73 0+ u,Cd 115.904 755 7.49 0+ ,,6Cd A table of radioactive isotopes is given in Appendix 1, on p237.

NMR [Reference: Cd(C104)2(aq);Cd(CH3)2]

lnCd 9.54 x 10'3 6.93 -5.6714 x 107 21.205

Relative sensitivity ('H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T V Frequency (‘H = 100 Hz; 2.3488T)/MHz

•ELECTRON

E E

113Cd 0.0109 7.6 -5.9328 x 107 22.182

SHELL

Ground state electron configuration: [Kr]4d'°5s2 Term symbol: 'S0 Electron affinity (M -> M )/kJ mol’1: -26 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M* M2t M3’ M4+ MSt M6* M7t

—> ->

-> -> -> —> M3* —>

M+ M2+ M3t M4+ M5+ M6+ M7+ MB+ M9+ M10*

Main lines in atomic spectrum

Electron binding energies/eV

Ionization energies/kj mol

K L,

867.6 1631 3616 (5300) (7000) (9100) (11 100) (14 100) (16400) (18 800)

Lu Lra Mi M„ Mra Mrv Mv

Is 2s 2pi/2 2p3/2 3s 3Pl/2 3p3/2 3d3/2 3d5/2

[WaveIength/nm(species)J 214.441 (II) 226.502 (II) 228.802 (I) (AA) 326.106 (D 643.847 (I)

26 711 4018 3727 3538 772.0 652.6 618.4 411.9 405.2

continued in Appendix 2, p255

•CRYSTAL Crystal structure (cell dimensions/pm), space group

h.c.p. [a = 297.94, c= 561.86), P63/mmc X-ray diffraction: mass absorption coefficients (/i/p)/cm2 g1: CuKa 231 MoKa 27.5 Neutron scattering length, fc/10"12 cm: 0.51 Thermal neutron capture cross-section, M )/kJ mol 45.5 Electron binding energies / eV

Ionization energies/kj mol

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M+ M2+ M3* M4+ M5* M6+ M7* M8t M9+

-> -> -> —> ->

—> ->

375.7 M+ 2420 M2+ (3400) M3+ (4400) M',+ (6000) M5+ (7100) M6t (8300) M7* M8+ (11300) M9* (12 700) M10+ (23 700)

| • C R Y S T A L

K L, Lu MB

M, M„ Mm M1V Mv

Is 2s 2pi/2 2p3/2 3s

35 985 5714 5359 5012 1211 1071 1003 740.5 726.6

3pu2 3p3/2

3d3,2 3d-,/2

Main lines in atomic spectrum

[Wavelength/nm(species)[ 455.528 (I) 460.376 (II) 522.704 (11) 592.563 (II) 852.113 (AA) (I) 895.347 (I)

continued in Appendix 2, p255

DA'r a

Crystal structure (cell dimensions/pm), space group

b.c.c. (78 K) {a = 614), Im3m High pressure forms: [a = 598.4), Fm3m; (a = 580.0), Fm3m X-ray diffraction: mass absorption coefficients (p/p)/cm2 g ‘: CuK„ 318 MoK(, 41.3 Neutron scattering length, h/10"12 cm: 0.542 Thermal neutron capture cross-section, crj bams: 29

•GEOLOGICAL Minerals Few are known. Mineral Formula Density Hardness Crystal appearance CesiumkupleskiteCs3(Mn,Fe)7(Ti,Nb)2Si8Q,4.(OH,F)7 3.68 4 trie., dull gold-brown Pollucite (Cs,Na)2Al2Si4012.nH20 2.94 6.5 cub., col., vit. Chief ores: pollucite; caesium is also found in

Abundances

lepidolite (see lithium)

Sun (relative to H = 1 x 1012): < 80

World production/tonnes y’: c. 20 (caesium

compounds) Main mining areas: Bernic Lake (Manitoba,

Canada), Bikita (Zimbabwe) and South-West Africa. Reserves/tonnes: c. 100 000 (60 000 at Bernic Lake) Specimen: available as small ingots in sealed

Earth’s crust/p.p.m.: 3 Seawater/p.p.m.: 3.0 x 10^ Atlanticsurface: n.a. Atlanticdeep: n.a. Pacific surface: n.a. Pacific deep: n.a. Residence time /years: 600 000 Classification: accumulating Oxidation state: I

ampoules. Danger!

47

Atomic number: 20 Relative atomic mass (12C = 12.0000): 40.078

CAS: [7440-70-2]

Description: Calcium is a silvery-white, relatively soft metal that is obtained by heating

calcium oxide (CaO) with aluminium metal in a vacuum. Although calcium metal is attacked by oxygen and water, the bulk metal is protected by an oxide-nitride film and can be worked as a metal. It is used in alloys and in the manufacture of zirconium, thorium, uranium and the rare earth metals. Calcium oxide (lime) is used in metallurgy, water treatment, chemicals industry, cement, etc. Radii/pm: Caz+ 106; atomic 197 (a-form); covalent 174 Electronegativity: 1.00 (Pauling); 1.04 (Allred); 2.2 eV (absolute) Effective nuclear charge: 2.85 (Slater); 4.40 (Clementi); 5.69 (Froese-Fischer)

Standard reduction potentials E*IV 0

II

-II

-1.045 2.224

2+

Ca'

1.574

-2.84

CaH2

Ca

-2.189

Ca02-CaO (hyd.)-0.076

Oxidation states Ca11

[Ar]

CaO, Ca02 (peroxide), Ca(OH)2, CaH2, CaF2, CaCl2 etc., Caz+ (aq), CaC03, CaS04.2H20 (gypsum) CaSO,.'/,H20 (plaster of Paris), CaC2 (calcium carbide), many salts, few complexes

•PHYSICAL

DATA

Melting point/K: 1112

AW^/kJ mol'1: 9.33 AWvap/kJ mol"1: 149.95

Boiling point/K: 1757

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid (a) Gas

AfH°lk] mol 1 0 178.2

AfG®/kJ mol'1 0 144.3

S'VI K'1 mol"1 41.42 154.884

C,,/I K'1 mol'1 25.31 20.786

Density/kg m'3: 1550 [293 K]; 1365 [liquid at m.p.] Molar volume/cm3: 25.86

Young’s modulus/GPa: 19.6

Thermal conductivity/W m'1 K'1: 200 [300 K]

Bulk modulus/GPa: 17.2

Coefficient of linear thermal expansion/K ': 22 x 10"6

Poisson’s ratio/GPa: 0.31

Rigidity modulus/GPa: 7.9

Electrical resistivity / Q m: 3.43 x 10"8 [293 K] Mass magnetic susceptibility/kg'1 m3: +1.4 x 10"” (s)

• BIOLOGICAL Biological role

Levels in humans

Essential to all species.

Blood/mg

Toxicity

Bone/p.p.m.:

Toxic intake: n.a.

dm'3:60.5 170 000 Liver/p.p.m.: 100-360 Muscle/p.p.m.: 140-700 Daily dietary intake: 600 - 1400 mg

Lethal intake: LD50 (carbonate, oral, rat) =

Total mass of element

6450 mg kg'1

in average (70 kgl person:

Non-toxic.

Hazards Calcium compounds are only toxic via their other components.

48

1.00 kg

Isolated in 1808 by Sir Humphry Davy at London, England.

Calcium

[I.atin, calx = lime] French, calcium-, German, Kalzium; Italian, calcio; Spanish, calcio

1 • N

U

[kal-sium]

CLEAR IfinH

Number of isotopes (including nuclear isomers): 16

Isotope mass range: 36 -> 51

Key isotopes Nuclide

Atomic mass

Natural abundance(%)

Nuclear spin /

Nuclear magnetic Uses moment p

"Ca

39.962 590 6

96.941

0+

0

E

“Ca

41.9586176

0.647

Ot

0

E

“Ca

42.958 7662

0.135

7/2-

“Ca

43.955 4806

2.086

0+

0

E

“Ca

45.953 689

0.004

Ot-

0

E

0

E

-1.31727

0.187 0+ 47.952533 “Ca A table of radioactive isotopes is given in Appendix 1, on p238.

NMR [Reference: CaClz (aq)] Relative sensitivity ('H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T-1s-1 Nuclear quadrupole moment/ m2 Frequency (‘H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

E, NMR

43Ca 6.40 x 10 3 0.0527 -1.8001 xlO7 -0.0408 x 10-28 6.728

DATA

Ground state electron configuration: [Ar]4s; Term symbol: ‘So Electron affinity (M M-)/kJ mol-1: -186 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M+ M2+ M3+ M4+ M5+ M®+ M7+ M8+ M9+

-4 M+ —> m2+ ;i -> M3". M4+ M5+ -> M®" -> M7+ —> M8+ —^ M9+ M10+

•CRYSTAL

Main lines in atomic spectrum

Electron binding energies /eV

Ionization energies/kj mol-1:

589. 1145 4910 6474 8144 10 496 12320 14 207 18191 20 385

K L, Ln Lin M, Mu Mra

Is 2s 2p„2 2p3/2 3s 3Pl/2 3P3/2

4038.5 438.4 349.7 346.2 44.3 25.4 25.4

[Wavelength/nm(species) ] 239.856 (I) 317.933 (II) 373.690 (II) 393.366 (II) 393.847 (II) 422.673 (I) (AA)

DATA

Crystal structure (cell dimensions/pm), space group

a-Ca f.c.c. (a = 558.84), Fm3m p-Ca b.c.c. (a = 448.0), Im3m y-Ca h.c.p. (a = 397, a = 649), P63mmc [may contain H] T(a -> p) = 573 K; T(p -> y) = 723 K X-ray diffraction: mass absorption coefficients (p/p)/cm2 g-1: CuK„ 162 MoK0 18.3 Neutron scattering length, bl 10-12 cm: 0.476 Thermal neutron capture cross-section, cra/barns:0.43

•GEOLOGICAL

m

0■- A T

Minerals Calcium occurs in many minerals. Mineral Anhydrite Aragonite Calcite Dolomite

Formula CaS04 CaC03 CaC03 CaMg(C03)2

Density 2.98 2.947 2.710 2.85

Hardness 3.5 3.5-4 3 3.4-4

Crystal appearance orth., vit./pearly col. orth., vit. col.-white rhom., vit. col. (gem, onyx) rhom., vit. col.

This table is continued in Appendix 3, p259. Chief ores: calcite, dolomite, gypsum (used in

Abundances

cement and plaster) anhydrite (used to make H2SO„)

Sun (relative to H = 1

World production/tonnes y-1: 2000 (calcium metal);

112x10® (lime, CaO) Main mining areas: common everywhere. Reserves/tonnes: almost unlimited Specimen: available as granules, pieces or

turnings. Care!

x

1012): 2.24 x 10®

Earth’s crust/p.p.m.: 41 000 Seawater/p.p.m.:

Atlantic surface: 390 Atlantic deep: 430 Pacific surface: 390 Pacific deep: 440 Residence time/years: 1 Classification: recycled Oxidation state: II

x

10®

49

Atomic number: 98 Relative atomic mass (l2C= 12.0000): 251.0796 (Cf-251)

CAS: [7440-71-3]

•CHEMICAL Description: Californium is a silvery, radioactive metal which does not occur naturally. It is

attacked by oxygen, steam and acids, but not alkalis. 252Cf is a strong neutron emitter, 1 pg releases 170 xlO6 neutrons per minute, and it is used in portable neutron sources used in moisture gauges, in core analysis in drilling oil wells, and in on-the-spot activation analysis in gold prospecting. It is also used in cancer therapy. Radii/pm: Cf+ 86; Cf+ 98; Cf* 117; atomic 169; van der Waals n.a. Electronegativity: 1.3 (Pauling); 1.2 (est.) (Allred); n.a. (absolute) Effective nuclear charge: 1.65 (Slater); n.a. (Clementi); n.a. (Froese-Fischer)

Standard reduction potentials f7V hi

IV

ii -1.91

acid

(Cf4+)

Cf3+

(Cf2+)

Cf

Oxidation states Cf

Cf"

f

cr cf

f f

CfO?, Cffir2, Cfl2 Cf203, CfF3, CfCl3 etc., Cf'* (aq), [Cf(C5H5)3] Cf02, CfF, suspected

•PHYSICAL Melting point/K: 1170

Af/^/kJ mol l: n.a. AWvap/kJ mol'1: 196

Boiling point/K: n.a.

Thermodynamic properties (298.15 K, o.l MPa) State Solid Gas

Afff ’/kJ mol"1 0 n.a.

AfG*7kJ mof' 0 n.a.

S*/J K-1 mol-1 n.a. n.a.

Cpl] Kntor1 25.98 n.a.

Density/kg m ’: n.a.

Young's modulus/GPa: n.a.

Molar volume/cm3: n.a.

Rigidity modulus/GPa: n.a.

Thermal conductivity/W m"1 K~': 10 (est.) [300 K]

Bulk modulus/GPa: n.a.

Coefficient of linear thermal expansion/K-1: n.a. Electrical resistivity I Si m: n.a.

Poisson’s ratio/GPa: n.a.

Mass magnetic susceptibility/kg 1 m3: n.a.

•BIOLOGICAL Biological role

Levels in humans

None.

nil

Toxicity

Daily dietary intake:

Toxic intake: n.a. Lethal intake: n.a.

Hazards Californium is rarely encountered outside certain prospecting and diagnostic uses. Special precautions are needed because it is not only a powerful source of radiation but also a dangerous neutron emitter.

50

nil

Total mass of element in average (70 kg) person:

nil

Discovery: see Nuclear Data section.

Californium

INamed after California] French, californium; CFerman, Californium; Italian. Californio; Spanish, Californio

•NUCLEAR

[kali-forn-iuhml

DATA

Discovery: Produced in 1950 by S.G. Thompson, K. Street Jr., A. Ghiorso and G.T. Seaborg at

Berkeley, California, USA . Number of isotopes (including nuclear isomers): 18

Isotope mass range: 239 -> 256

Key isotopes Nuclide

Atomic mass

Half life (T„2) Decay mode and energy (MeV)

Nuclear Nucl. mag. Uses spin I moment u

mCf

246.068800

1.49 h

a (6.869); y

0+

2«cf

247.071 020

3.11 h

EC (0.65) 99.96%; a (6.55) 0.04%; y

7/2+

ma

248.072 183

334 d

a (6.369); no y

0+

»Cf *°Cf

249.074844

351 y

a (6.295); y

9/2-

250.076400

13.1 y

a (6.129); no y

0+

aia

251.079580

900 y

a (6.172); y

1/2+

K2a

252.081 621

2.64 y

a (6.217); 96.9%; SF3.1%;y

Of

®Cf

253.085127

17.8 d

|3- (0.29)99.7%; a (6.126) 0.3%

7/2+

254a

254.087318

60.5 d

SF 99.7%; a (5.930)0.3%

0+

1.4 h

P

R, D, T

Other isotopes of californium have half-lives shorter than 1 hour.

NMR [Reference: n.a.] Relative sensitivity ('H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T 's'1 Nuclear quadrupole moment/m2 Frequency ('H = 100 Hz; 2.3488T)/MHz

252 Cf n.a. n.a. n.a. n.a. n.a.

Ground state electron configuration: [Rn]5f107s2 Term symbol: % Electron affinity (M -> M")/kJ mol'1: n.a. Ionization energies/kj mol l:

1. M

-> M+

608

Electron binding energies/eV

Main lines in atomic spectrum

n.a.

[Wavelength/nmfspecies)] 339.222 0) 353.149 (D 354.098 (I) 359.877 (I) 360.532 (I) 361.211 (II) 362.676 (II)

•CRYSTAL Crystal structure (cell dimensions/pm), space group

a-Cf h.c.p. /J-Cf f.c.c. 1\a -> p) = 1173 K X-ray diffraction: mass absorption coefficients (/z/p)/cm2 g CuK„ n.a. MoK„ n.a. Neutron scattering length, b/10"12 cm: n.a. Thermal neutron capture cross-section, cra/bams:2900 (251Cf)

• GEOLOGICAL

DATA

Minerals Not found on Earth. Chief source: californium-249 and 252 are

Abundances

obtained in gram quantities by the bombardment of 239Pu with neutrons. World production: in excess of 100 g has been produced, and a few grams are made each year.

Sun (relative to H = 1

x

1012): n.a.

Earth’s crust/p.p.m.: nil Seawater/p.p.m.: nil

Specimen: commercially available under licence -

see Key.

51

Atomic number: 6 Relative atomic mass (12C = 12.0000): 12.011

CAS: (7440-44-0) .

•CHEMICAL Description: Carbon occurs in three forms: graphite, diamond and buckminsterfullerene C60.

It is mainly used in its amorphous forms: as coke in steel making, as carbon black in printing, and as a filler, and as activated charcoal in sugar refining, water treatment and in respirators. Radii /pm: C4" 260; atomic 77; covalent C-C 77; C=C 67; C=C 60; van der Waals 185 Electronegativity: 2.55 (Pauling); 2.50 (Allred); 6.27 eV (absolute) Effective nuclear charge: 3.25 (Slater); 3.14 (Clementi); 2.87 (Froese-Fischer)

Standard reduction potentials F7V VI acid

base

II

0

-II

C02

-°-1Q6— CO-^-C-^— CH4

C02

~°'20

HC02H 0034

C02

'‘-01

HC02“

HCHO 0232

~1'07-- HCHO

°'59

CH3OH

0 59

CH4

CH3OH

~°'2

CH4

Oxidation states

Covalent bonds

This concept is rarely used in discussing carbon and its compounds because of their subtleties of bonding. However for simple compounds with a single carbon we can use it:

Bond C-H C-C C=C C=C C-N C=N C=N C-0

C-N C-" Civ

[Ne] s2p4 [He]

CH„ CO C02, CO;

c=o c=o

-IV

r/ pm 190 154 134 120

El kj mol 411 346 602 835

147 130 116 143 120 113

305 615 887 358 799 1072

Other bonds to carbon: see other elements

Melting point/K: c. 3820 (diam.); 3800 (graph.); 800 (C60, sublimes) AW^/kJ mol ‘: 105.1 Boiling point/K: 5100 (sublimes)

AWvap/kJ moT1: 710.9

Thermodynamic properties (298.15 K, 0.1 MPa) State AfH^/kJ mol1 Solid (graphite) 0 Solid (diamond) 1.895 Gas 716.682

AfG®/kJ mol ' 0 2.900 671.257

S*/J K 1 mol1 5.740 2.377 158.096

C„/J K 8.527 6.113 20.838

Density/kg mf3: 3513 (diam); 2260 (graph.); 1650 (C60) [293 K] Molar volume/cm3: 3.42 (diam.) Thermal conductivity/W nr1 K ': 990-2320 (diam.); 5.7L; I96011 (graph.) [298 K) Coefficient of linear thermal expansion/K1:1.19 x 10 6 (diam.) Electrical resistivity In m: 1 x 10" (diam.); 1.375x 10‘5 (graph.); 1 x 1014 (C,yj) [293 K] Mass magnetic susceptibility/kg 1 m3: -6.3 x 10"'1 (graph.); -6.2 x 10~9(diam.)

• BIOLOGICAL Biological role

Levels in humans

Constituent element of DNA.

Blood/mg dm 3:0.0016-0.075 Bone/p.p.m.: 300 000 Liver/p.p.m.: 670 000 Muscle/p.p.m.: 670 000

Toxicity Non-toxic as the element, but some simple compounds can be very toxic, such as CO or cyanide CN~.

Daily dietary intake: 300 Total mass of element

Lethal intake: n.a.

in average (70 kg) person:

Hazards Carbon black can be a nuisance dust but is not itself dangerous, although soot may harbour carcinogenic materials.

52

g 16 kg

Occurs naturally as graphite and diamond; known to prehistoric humans.

Carbon

(Latin, carbo = charcoal) French, carbone; German, Kohlenstoff-, Italian, carbonio-, Spanish, carbono

•NUCLEAR

[kar-bon]

DATA Isotope mass range: 9 -> 16

Number of isotopes (including nuclear isomers): 8

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear magnetic Uses moment /.i

Nuclear spin I

12.000000000* 98.90 0+ I2C 13.003 354 826 1.10 1/2— »C * by definition. A table of radioactive isotopes is given in Appendix 1, p238.

NMR [Reference: Si(CH3)4]

0 +0.702 411

NMR

13C 0.0159 1.00 (by defn.) 6.7263 x 107

Relative sensitivity ('H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T ' s'1 Nuclear quadrupole moment/m2 Frequency (*H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

25.144

DATA

Ground state electron configuration: [He]2s22p2 Term symbol: 3P0 Electron affinity (M -> M )/kJ mol'1: 121.9 Ionization energies/kj mol':

1. M 2. M* 3. M2+ 4. M3* 5. M4+ 6. M5t

-> -+ -+ -+ -+ -+

M4 M2+ M3+ M4* M5+ M6*

•CRYSTAL

1086.2 2352 4620 6222 37827 47 270

Electron binding energies /eV

Main lines in atomic spectrum

K

[Wavelength/nm(species)] 247.856 (I)

Is

284.2

283.671 (II) 426.726 (II) 723.642 (II)

DATA

Crystal structure (cell dimensions/pm), space group

Cubic diamond (a = 356.703), Fd3m Hexagonal diamond [a = 252, c = 412), P6,/mmc Hexagonal graphite (a = 246.12, c= 670.78), P63mc Rhombohedral graphite (a = 364.2, a = 39” 30'), R3m Hexagonal carbon [chaoite] (a = 894.8, c= 1408) F.c.c. buckminsterfullerene C60 (a= 1414) X-ray diffraction: mass absorption coefficients (p/p)/cm2 g l: CuK„ 4.60 MoK„ 0.625 Neutron scattering length, b/1012 cm: 0.66460 Thermal neutron capture cross-section, 151

Key isotopes Nuclide

Atomic mass

Natural abundance(%)

Nuclear spin /

Nuclear magnetic Uses moment p

»Ce

135.907 140

0.19

0+

E

13“Ce

137.905 985

0.25

0+

E

“Ce

139.905433

88.48

0+

E

141.909 24 11.08 0+ ,42Ce A table of radioactive isotopes is given in Appendix 1, on p238.

E

none

NMR [Reference: none]

•ELECTRON

SHELL

DATA

Ground state electron configuration: [Xe]4f5d6s2 Term symbol: 3H, Electron affinity (M -> M~)/kJ mol1: < 50 Ionization energies/kj mol ':

527. 1047 M* 1949 M2+ 3547 M3’ (6800) M4t (8200) M5+ (9700) Mc” M7’ -> M8* (11 800) M8* -> M9+ (13 200) M9’ —> Ml0+ (14 700)

1. M

2. 3. 4. 5. 6. 7. 8. 9. 10.

—> M* M2+ -> M3" M4* -> M5+ M6* M7+

•CRYSTAL

Electron binding energies/eV

K L, Lit Lin M, M„ Mm MIV Mv

Is

40443 6548 6164 5723 1436 1274 1187 902.4 883.8

2s 2pm 2p3/2 3s

3Pl/2 3p,/2

3d3/2 3d5/2

Main lines in atomic spectrum

[Wavelength/nm(species)] 349.275 (II) 395.254 (II) 399.924 (II) 401.239 (II) 413.380 (II) 418.660 (II)

continued in Appendix 2, p255

DATA

Crystal structure (cell dimensions/pm), space group

a-Ce f.c.c. (a = 485), Fm3m P-Ce hexagonal (a = 367.3, c= 1180,2), P63/mmc y-Ce f.c.c. (a = 516.01), Fm3m 5-Ce f.c.c. (a = 412), Im3m = 441 K X-ray diffraction: mass absorption coefficients (p/p)/cm2 g_1: CuK„ 352 MoK„ 48.2 Neutron scattering length, 7?/10 12 cm: 0.484 Thermal neutron capture cross-section, 'j,/barns: 0.6

•GEOLOGICAL Minerals Mineral Formula Density Hardness Crystal appearance Bastnasite-Ce* (Ce,La, etc,) C03F 4.9 4-4.5 hex., vit./greasy yellow Monazite-Ce* (Ce,La,Nd,Th,etc.)P04 5.20 5-5.5 mon., waxy/vit. yellow-brown •Varieties of these minerals that are particularly rich in cerium. Chief ores: monazite, bastnasite. Perovskite

Abundances

(Ti mineral) can also be rich in cerium

Sun (relative to H = 1 x 1012): 35.5

World production/tonnes y l: 24 000

Earth’s crust/p.p.m.: 68 Seawater/p. p.m.:

Main mining areas: USA, Brazil, India, Sri Lanka, Australia, China.

Reserves/tonnes: c. 15 x 106 Specimen: available as chips, ingots or powder.

Safe.

Atlantic surface: 9.0 x 10'6 Atlantic deep: 2.6 x lO'4 Pacific surface: 1.5 x 10s Pacific deep: 0.5 x lO-6 Residence time/years: 100 Classification: scavenged Oxidation state: III

55

Atomic number 17 Relative atomic mass (12C = 12.0000): 35.4527

•CHEMICAL

CAS: [7782-50-5]

DATA

Description: Chlorine is a yellow-green, dense, sharp-smelling gas (Cl2) produced on the

million tonne scale by the electrolysis of sodium chloride solution. It is used as a bleaching agent and as a sterilising agent for water supplies. It is a key industrial chemical and used for the manufacture of organochlorine solvents and PVC. Radii/pm: Cl 181; covalent 99; van der Waals 181 Electronegativity: 3.16 (Pauling); 2.83 (Allred); 8.30 eV (absolute) Effective nuclear charge: 6.10 (Slater); 6.12 (dementi); 6.79 (Froese-Fischer)

Standard reduction potentials £"7V V

VII

IV

III

I

-I 1.584

1.659

1.181 _

acid

1.201

,

1.175

,

1.188

1.701

1.630

[

1.35828

1_1.468_1 1.277

1.287 0.890

0.295

base

0.374

[C104]

I

_ -0.481

1.071

Cl6olCl03r

CIO,

Oxidation states [Ar] s2p5 s2p4 s2p2 s2p‘ s2 s1 [Ne]

CIO,

0.681

,

_

0.421

,

1.35828

0.622

Covalent bonds

CP (aq), HC1, NaCl etc. Cl2 C120, HOC1, salts, CIO" (aq), C1F NaC102, CIF3 C102 HCIO3, salts, CIO3- (aq), C1F5, C1F,0 CIA C1207, HCIO4, salts, C104 (aq), CIFO3

Bond r/ pm El kj moT Cl—O 170 218 Cl—F 163 249 Cl—Cl 199 240 For other bonds to chlorine: see other elements

PHYSICAL Melting point/K: 172.17

AW fusion/kj mol 6.41 AWvap/kJ mol1: 20.4033

Boiling point/K: 239.18 Critical temperature/K: 417 Critical pressure/ kPa: 7700

Thermodynamic properties (298.15 K, 0.1 MPa) State Gas (Cl2) Gas (atoms)

AfW*7kJ mol1 0 121.679

AfG®/kJ mol1 0 105.680

SVJ K 1 mol” 223.066 165.198

Cp/J K~l mob1 33.907 21.840

Density/kg nr3: 2030 [113 K]; 1507 [239 K]; 3.214 [273 K] Molar volume/cm3: 17.46 [ 113 K] Thermal conductivity/W rn 1 K~l: 0.0089 [300 K] (g) Mass magnetic susceptibility/kg' m3: -7.2 x 10 s (g)

•BIOLOGICAL

DATA

Biological role

Levels in humans

Chloride, CF, is essential to many species, including humans. Cl2 is very toxic; chloride is non-toxic.

dm 3: 2890 (chloride) 900 (chloride) Liver/p.p.m.: 3000 - 7200 (chloride) Muscle/p.p.m.: 2000 - 5200 (chloride) Daily dietary intake: 3.00 - 6.50 g

Toxic intake: affects eyes and lungs at

Total mass of element

3 p.p.m. in air

in average (70 kg) person:

Toxicity

Lethal intake: LC50 (Cl2, inhalation, human) =

600 ppm for 5 minutes

Hazards Chlorine is corrosive; its vapour attacks the eyes and lungs. In air, 15 ppm Cl2 produces throat irritation, 50 ppm is dangerous even in short doses. TWA = 0.5 ppm. 56

'

-CIO -Cl2 —-Cl

0.488

I

Cl-1 Cl° Cl' cr cr Clv cr Cl™

'

[C104] -- [C103] -C102-HC102-HCIO --Cl2-Cl

Blood/mg

Bone/p.p.m.:

95 g

Discovered in 1774 by C.W. Scheele at Uppsala, Sweden.

Chlorine

[Greek, chloros = pale green] French, chlore-, German, Chtor, Italian, cloro; Spanish, cloro

[klor-een]

warn

•NUCLEAR Number of isotopes (including nuclear isomers): 13

Isotope mass range: 31 - -> 41

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

35C1

34.968852721

37d

36.965902 62

Nuclear spin I

Nuclear magnetic Uses moment p

75.77

3/2+

+0.821 873 6

E, NMR

24.23

3/2+

+0.684 123 0

E, NMR

A table of radioactive isotopes is given in Appendix 1, on p238.

NMR [Reference: NaCl (aq)]

35C1 4.70 xlO'3 20.2 2.6210 x 107 -0.08165 xlO'28 9.798

Relative sensitivity (‘H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T''s_1 Nuclear quadrupole moment/nr Frequency ('H = 100 Hz; 2.3488T)/MHz

•ELECTRON

37C1 2.71 x 10'3 3.8 2.1718x 107 -0.06435 x 10'28 8.156

SHELL

Ground state electron configuration: [Ne]3s23p5 Term symbol: 2P3/2 Electron affinity (M -> M')/kJ mol'1: 349.0 Ionization energies/kj mol 1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M* M2* M3+ M4+ M5+ M6+ M7’ M8+ M9+

—>

-> -> -» —> ->

M+ M2+ M3+ M4+ M5+ M6+ M7+ M8* M9+ M10+

•CRYSTAL

1251.1 2297 3826 5158 6540 9362 11020 33 610 38 600 43 960

Electron binding energies /eV

Main lines in atomic spectrum

K L, L,,

Is 2s 2p172

2822 270 202

Liu

2p3/2

200

[Wavelength/nm(species)] 479.455 (II) 489.677 (II) 542.323 (II) 837.574 (I) 858.597 (I)

DATA

Crystal structure (cell dimensions/pm), space group

Tetragonal (a = 856; c = 612), P4/ncm Orthorhombic (a = 624; b = 448; c - 826), Cmca T(tetragonal -+ orthorhombic) = 100 K X-ray diffraction: mass absorption coefficients (p/p)/cm2 g *: CuK(1 106 MoK„ 11.4 Neutron scattering length, h/10 12 cm: 0.95770 Thermal neutron capture cross-section, ap/kI mol'1: 348.78

Boiling point /K: 2945

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

AtH*7kJ mol1 0 396.6

AfG®/kJ mol1 0 351.8

S*7J K 1 mol'1 23.47 174.50

C„/J K 1 mol1 23.35 20.79

Density/kg m 3: 7190 [293 K]; 6460 [liquid at m.p.[

Young’s modulus/GPa: 279

Molar volume/cm3: 7.23

Rigidity modulus/GPa: 115.3

Thermal conductivity/W m

1

K1: 93.7 [300 K]

Coefficient of linear thermal expansion/K'1:6.2 x 10-6 Electrical resistivity /n m: 12.7 x 10

Bulk modulus/GPa: 160.2 Poisson’s ratio/GPa: 0.21

[273 K] Mass magnetic susceptibility/kg'1 m3: +4.45 x 10~8 (s) 8

•BIOLOGICAL Biological role

Levels in humans

Essential to some species, including humans; it is also stimulatory.

Blood/mg dm'3:0.006-0.11 Bone /p.p.m.: 0.1- 0.33 Liver /p.p.m.: 0.02 - 3.3 Muscle/p.p.m.: 0.024 - 0.84

Toxicity Toxic intake: 200 mg

Daily dietary intake:

0.01 - 1.2 mg

Lethal intake: metal, oral, human =

Total mass of element

70 mg kg'1. LD^ (acetate, oral, rat) = 11 000 mg kg'1

in average (70 kg) person:

Hazards Chromium is a human poison by ingestion, it is also a suspected carcinogen. Chromates have a corrosive action on skin and tissue. 58

14 mg

Discovered and isolated in 1780 by Nicholas Louis Vauquelin at Paris, France.

Chromium

(Greek, chroma = colour] French, chrome; German, Chrom; Italian, cromo; Spanish, cromo

Ikroh-mi-uhm)



•NUCLEAR

mmfr

Number of isotopes (including nuclear isomers): 13

Isotope mass range: 45 —> 57

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

“Cr

49.9460464

4.345

0+

52Cr

51.940509 8

83.789

0+

“Cr

52.9406513

9.501

Nuclear spin /

Nuclear magnetic Uses moment p E E -0.474 54

3/2-

.

E, NMR

53.9388825 2.365 0+ 5,Cr A table of radioactive isotopes is given in Appendix 1, on p238.

E

53Cr 9.03 x nr1 0.49 -1.5120 xlO7 -0.150 xlO28 5.652

NMR [Reference: [CrOJ2-] Relative sensitivity ('ll = 1.00) Receptivity ( 13C=1.00) Magnetogyric ratio/rad T 1 s1 Nuclear quadrupole moment/m2 Frequency (:H = 100 Hz; 2.3488T)/MHz

Ground state electron configuration: |Ar|3d54s' Term symbol: 7S3 Electron affinity (M -> M~)/kJ mol"1: 64.3 Ionization energies/kl mol ‘:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M* M24 M3* M4+ M5* M6+ M7* M8+ M9+

-> -> -v -> -» -»

M+ M2+ M3+ M4+ M5+ M6t M7+ M8+ -» M9+ -» M10+

652.7 1592 2987 4740 6690 8738 15 550 17 830 20220 23 580

Main lines in atomic spectrum

Electron binding energies /eV

K u Ln Lin M, M„

Is 2s 2p„2 2p3/2 3s 3Pl/2 3P3/2

[Wavelength/nm(species)l 357.869 (I) (AA) 359.349 (I) 360.533 (I)

5989 696.0 583.8 574.1 74.1 42.2 42.2

425.435 (I)

427.480 (I) 428.972 (I) 520.844 (I)

•CRYSTAL Crystal structure (cell dimensions/pm), space group

b.c.c. {a = 288.46), Im3m X-ray diffraction: mass absorption coefficients (ji/p)lcm2 g'1: CuK0 260 MoKn 31.1 Neutron scattering length, bl 10“12 cm: 0.3635 Thermal neutron capture cross-section, 64

Number of isotopes (including nuclear isomers): 17

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin I

Nuclear magnetic Uses moment fi

59Co

58.933 197 6

100

7/2-

+4.627

NMR

A table of radioactive isotopes is given in Appendix 1, on p239.

59Co 0.28 1570 6.3472 xlO7 +0.420 xl0-; 23.614

NMR [Reference: K3[Co(CN)6]J Relative sensitivity (JH = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T-1 s-1 Nuclear quadrupole moment/m2 Frequency (‘H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

DATA

Ground state electron configuration: [Ar]3d74s2 Term symbol: 4F9/2 Electron affinity (M -> M')/kJ mol-1: 63.8 Electron binding energies /eV

Ionization energies /kj mol ’:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M" M2+ M3+ M4+ M5+ M6* M7+ M8* M9+

-+ -+ -> -+ -> -» -» -> -> -+

M+ M2+ M3+ M4+ M5+ M6+ M7t M8t M9" M10+

K L| Lii I+ii M, Ma Mhi

760.0 1646 3232 4950 7670 9840 12400 15 100 17 900 26600

•CRYSTAL

Is 2s 2Pl/2 2p3/2 3s 3pil2 3p3/2

7709 925.1 793.2 778.1 101.0

58.9 58.9

Main lines in atomic spectrum

[Wavelength/nm(species)] 240.725 (I) (AA) 242.493 (I) 340.512 (I) 344.364 (I) 345.350 (I)

350.228 (I) 356.938 (I)

DAT

Crystal structure (cell dimensions/pm), space group

a-Co f.c.c. (a = 354.41), Fm3m e-Co h.c.p. (a = 250.7, c = 406.9), P63/mmc T(ct -> e) = 690 K X-ray diffraction: mass absorption coefficients {/u/p)lcm2 g ': CuKk 313 MoK„ 42.5 Neutron scattering length, b/10-12 cm: 0.278 Thermal neutron capture cross-section, M )/kJ mob’: 118.5 Ionization energies/kj mol ': 745.4 1. M —> M4 1958 2. M* M24 m3+ 3554 3. M24 5326 4. M34 —> M44 7709 5. M44 —» M54 (9940) 6. M54 —> m6+ 7. Mfi+ —> M74 (13 400) 8. M7+ M84 (16 000) 9. MSt —> M94 (19 200) 10. M94 —> M104 (22 400)

Electron binding energies/eV 8979 Is K 2s 1096.7 L, 952.3 2Pl/2 Lh 932.5 2p3/2 I+n 3s 122.5 M, 77.3 3Pl/2 M„ 75.1 Mm 3p3/2

Main lines in atomic spectrum [Wavelength/nm (species)] 216.509 (I) 217.894 (I) 324.754 (I) (AA) 327.396 (I) 521.820(1)

•CRYSTAL Crystal structure (cell dimensions/pm), space group f.c.c. (a = 361.47), Fm3m X-ray diffraction: mass absorption coefficients (p/p) I cm2 g‘: CuKa 52.9 MoK(, 50.9 Neutron scattering length, h/10 12 cm: 0.7718 Thermal neutron capture cross-section, era/barns:3.78

•GEOLOGICAL Minerals Crystals of native copper occur naturally and there are small deposits in the USA, Germany, Zambia, Chile and Italy.

Mineral

Formula

Atacamite Azurite Bornite Brochantite Chalcanthite Chalcocite Chalcopyrite

Cu,Cl(OH)3 Cu(C03)2(0H)2 Cur,FeS4 Cu4(S04)(0H)4 CuS04.5H20 Cu2S CuFeS2

Density

Hardness

3.77 3.773 5.07 3.97 2.286 5.7 4.2

3-3.5 3.5-4 3 3.5-4 2.5 2.5-3 3.5-4

Crystal appearance orth., adarn. vit. green mon., vit. blue (ornamental) tet., met. copper-red brown mon., vit. green trie., vit. blue hex., met. blackish-grey tet., met. yellow

This table is continued in Appendix 3 on page 259. Chief ores: chalcopyrite accounts for c. 80% of world's copper (with silver and gold as by-

Abundances Sun (relative to H = 1 x 10,_): 1.15 x 104

products), chalcanthite, brochantite. Malachite Earth’s crust/p.p.m.: 50 Seawater/p.p.m.: is used for polished slabs, tables and columns. World production / tonnes y ': 6.54 x 106 Main mining areas: chalcopyrite in USA, Zaire, Zambia, Canada, Chile, Cyprus, Russia; malachite in Russia, Zaire, Zambia, Chile, Australia; chalcanthite in Chile. Reserves/tonnes: 310xl06

Atlantic surface: 8.0 x 10 s Atlantic deep: 12

x

Pacific surface: 8.0

10'5 x

10'

Pacific deep: 28 x 10“3 Residence time/years: 3000 Classification: recycled Oxidation state: II

Specimen: available as bars, foil, powder, shot, turnings or wire. Safe.

63

Cm

Atomic number: 96

CAS:

Relative atomic mass (nC = 12.0000): 247.0703 (Cm-247)

(7440-51-9]

Description: Curium is a silvery, radioactive metal. It is attacked by oxygen, steam and acids,

but not alkalis. The metal itself was produced by the reduction of CmF3 with barium vapour at 1200 °C. It is a potential isotope power source because it gives off three watts of heat energy per gram. Radii/pm: Cm41 88; Cm3* 99; Cm2* 119; atomic 174 Electronegativity: 1.3 (Pauling); 1.2 (est.) (Allred); n.a. (absolute) Effective nuclear charge: 1.80 (Slater); n.a. (dementi); n.a. (Froese-Fischer)

Standard reduction potentials ElV IV

III

II

0

-2.06 1-1

1 o, Cm3

-3.7

acid

Cm4* —-

base

Cm02- Cm(OFD3

-

+0.7

o.

-1.2

1

(Cm21)-Cm -2.53

Cm

Oxidation states Cm" f7d‘ Cm1" f7

Cm,v f

CmO Cm203, Cm(OH)3, CmF3, CmCl3 etc., [CmCl6]3*, Cm3*(aq), [Cm(C5H5)3] Cm02, CmF4, Cm4* (aq) very unstable

•PHYSICAL

DATA

Melting point/K: 1610±40

AH^/kJ mol': n.a. AH,ap/kJ moT1: 387

Boiling point/K: n.a.

Thermodynamic properties (298.15 K, 0.1 MPa) A,H°lk) moF1 0 n.a.

State Solid Gas

A(G®/kJ moT1 0 n.a.

Density/kg m-3: 13 300 [293 K]

S®/J K~' mol-' n.a. n.a.

C„/J K'1 moT1 25.98 n.a.

Young’s modulus/GPa: n.a.

Molar volume/cm3: 18.6

Rigidity modulus/GPa: n.a.

Thermal conductivity/W m 1 1C1: 10 (est.) [300 K]

Bulk modulus/GPa: n.a.

Coefficient of linear thermal expansion/K_1: n.a. Electrical resistivity In m: n.a.

Poisson’s ratio/GPa: n.a.

Mass magnetic susceptibility/kg"1 m3: approaches that of

gadolinium [c. 1

x

10

5]

•BIOLOGICAL Biological role

Levels in humans

None.

nil

Toxicity

Daily dietary intake:

Toxic intake: n.a. Lethal intake: n.a.

Hazards Curium is never encountered normally. It is dangerous because it accumulates in bone marrow and its intense radiation destroys red cells. This element is only to be found inside nuclear facilities or research laboratories.

64

nil

Total mass of element in average (70 kg) person:

nil

Discovery; see Nuclear Data section. [Named after Pierre and Marie Curie)

Curium

French, curium; German, Curium; Italian, curio; Spanish, curio

[kyuhr-iuhm]

•NUCLEAR

DATA

Discovery: Curium was prepared in 1944 by G.T. Seaborg, R.A. James and A. Ghiorso at Berkeley, California, USA. Number of isotopes (including nuclear isomers): 14

Isotope mass range: 238 -» 251

Key isotopes Nuclide

Atomic mass

Half life (T„2) Decay mode and energy (MeV)

Nuclear Nucl. mag. Uses spin I moment /u

240Cm

240.055503

27 h

a (6.397)

24,Cm

241.057645

32.8 d

EC (0.77) 99%; a (6.184) 1%; y

0+ 1/2+

242Cm

242.058 830

162.8 d

a (6.126); y

0+

243Cm

243.061381

28.5 y

a (6.167); y

5/2+

244Cm

244.062747

18.1 ly

a (5.902); y

0+

245Cm

245.065483

8500 y

a (5.623); y

7/2+

246Cm

246.067218

4780 y

a (5.476); y

0+

247Cm

247.070347

1.56xl07y

a (5.362); y

9/2-

2®Cm

248.072343

a (5.162); 92%; SF 8%; noy

0+

Z50Cm

250.078352

3.4 x 10s y c. 9000 y

SF; a (5.27)

0+

0.41 R 0.5 +0.37 R

Other radioisotopes of curium have half-lives shorter than 5 hours.

NMR n.a.

•ELECTRON

SHELL

DATA

Ground state electron configuration: [Rn]5f6d‘7s2 Term symbol: 9D2 Electron affinity (M -> M )/kJ mol”1: n.a.

Ionization energies/kj mol”1: 1. M -+ M* 581

•CRYSTAL

Electron binding energies/eV n.a.

Main lines in atomic spectrum* [Wavelength/nm(species)] 299.939 (1) 310.969 (I) 311.641 (I) 313.716 (I) 314.733 (I) 315.510 (I) 315.860 (I) *first seven lines associated with the neutral atom

DATA

Crystal structure (cell dimensions/pm), space group cr-Cm h.c.p. p-Cm f.c.c. T[a -> P) = 1550 K X-ray diffraction: mass absorption coefficients (p/p)lcm2 g

CuKa n.a. MoK„ n.a.

Neutron scattering length, bl 10'12 cm: 0.95 Thermal neutron capture cross-section, a,/barns: 79

• GEOLOGICAL

DATA

Minerals None. Chief source: curium-242 and 244 are obtained in kilogram quantities by the bombardment of 239Pu with neutrons. World production: several kilograms are produced each year.

Abundances Sun (relative to H = 1 x 1012): n.a. Earth’s crust/p.p.m.: nil Seawater/p.p.m.: nil

Reserves: attempts are being made to convert plutonium into curium so potential stocks may be quite large. Specimen: commercially available, under licence - see Key.

65

Atomic number:

105

CAS:

Relative atomic mass (13C = 12.0000): 262.114 (Db-262)

•CHEMICAL

[3850-35-4]

DATA

Description: Dubnium is a radioactive metal which does not occur naturally, and is of research interest only. Radii/pm: Db" 68 (est.); atomic 139 (est.) Electronegativity: n.a. Effective nuclear charge: n.a.

Standard reduction potentials El V V

0

Db5+_^8(esU

Db

Oxidation states Db" Dbv

d' [f14]

? most stable?

PHYSICAL Melting point/K: n.a.

AWf^/W mob1: n.a. AWvap/kJ mob1: n.a. Atf^/kJ mob1: 795 (est.)

Boiling point/K: n.a.

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

Af/D'/kJ mob1 0 n.a.

AtGe/kJ mob1 0 n.a.

Se/I K-1 mol 1 n.a. n.a.

Density/kg m-3: 29 000 Molar volume/cm3: n.a. Thermal conductivity/W m 1 K1: n.a. Coefficient of linear thermal expansion/K“‘: n.a. Electrical resistivity/Q m: n.a. Mass magnetic susceptibility/ kg 1 m3: n.a.

•BIOLOGICAL

A T A

Biological role

Levels in humans

None.

nil

Toxicity

Daily dietary intake:

Toxic intake: n.a. Lethal intake: n.a.

Hazards Dubnium is never encountered normally, and only a few atoms have ever been made. It would be dangerous because of its intense radioactivity.

66

nil

Total mass of element in average (70 kg) person:

nil

C,/J K 1 mol1 n.a. n.a.

Discovery: see Nuclear Dala section.

& m

[Named after Dubna]

m

Dubnium

French, dubnium; German, Dubniuirv, Italian, dubnio; Spanish, dubnio

[dub-ni-uhm)

•NUCLEAR Discovery: Isotopes 260 and 261 were tentatively reported in 1967 by a group of scientists at

Dubna, near Moscow, Russia. Isotope 260 was confirmed at both Berkeley, California, USA and Dubna in 1970. IUPAC concluded in 1992 that credit for the discovery should be shared between both groups. Number of isotopes (including nuclear isomers): 7

Isotope mass range: 255 -> 262

Key isotopes Nuclide

Atomic mass

Half life (T„z) Decay mode and energy (MeV) c. 1.5 s

SF

S7Db

257.107770

1.3 s

a; SF

^Db

258.109020

4.4 s

25SDb

259.109580

c. 1.2s

a; EC (5.3) SF

“Db

260Db

260.111040

1.5 s

a; SF

261Db

261.111820

1.8 s

a; SF

262Db

262.113760

34 s

EC; a

27 s

SF; a

263Db

Nuclear Nucl. mag. Uses spin / moment n

NMR (Not recorded]

•ELECTRON

SHELL

Ground state electron configuration: [Rn]5f>46d37s2 Term symbol: 4F3/2 Electron affinity (M -> M~)/kJ mol'1: n.a. Ionization energies/kj mol1:

1. M

_» M+

640 (est.)

Electron binding energies/eV

Main lines in atomic spectrum

n.a.

[Wavelength/nm(species)( n.a.

•CRYSTAL Crystal structure (cell dimensions/pm), space group

X-ray diffraction: mass absorption coefficients

cm2 g ': CuKa n.a. MoKa n.a.

Neutron scattering length, b/10 12 cm: n.a. Thermal neutron capture cross-section, (7,/barns: n.a.

• GEOLOGICAL Minerals Not found on Earth.

several atoms of dubnium have been made from 249Cf by bombarding with 15N nuclei

Abundances

(249Cf + 15 N —> 260Db + 4n), or from 249Bk by bombarding with 180 nuclei.

Earth’s crust/p.p.m.: nil Seawater/p.p.m.: nil

Chief source:

Sun (relative to H = 1 x 1012): n.a.

Specimen: not available commercially.

67

■-

a,r,

|i

Atomic number: 66

CAS:

Relative atomic mass (,2C= 12.0000): 162.50

[7429-91-6]

.

•CHEMICAL

DATA

Description: Dysprosium is a hard, silvery metal of the so-called rare earth group (more

correctly termed the lanthanides). It is oxidised by oxygen, reacts rapidly with cold water, and dissolves in acids. Dysprosium is used in alloys for making magnets. Radii/pm: Dy3* 91; atomic 177; covalent 159 Electronegativity: 1.22 (Pauling); 1.10 (Allred); n.a. (absolute) Effective nuclear charge: 2.85 (Slater); 8.34 (Clementi); 11.49 (Froese-Fischer)

Standard reduction potentials IT7V IV

III

II

o

_-2.29_ .

57

C”

-2ti

-23>

acid

Dy4+ —— Dy3 -Dy2*-Dy

base

Dy02-Dy(OH)3-Dy

3.5

-2.80

Oxidation states Dy" Dy"'

f° f

Dyw

f

DyCl2, Dyl2 Dy203, Dy(OH)3, [Dy(OH2)J3+ (aq), Dy3* salts, DyF3, DyCl3 etc., salts, [DyClB]3' Cs3DyF7

• PHYSICAL Melting point/K: 1685

AWf^/kJ mol17.2

Boiling point/K: 2835

A//vap/kJ mol"1: 293

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

Af// M“)/kJ mol-1: < 50 Ionization energies/kj mol 1:

1. M

-+ M+

•CRYSTAL

619

Electron binding energies / eV

Main lines in atomic spectrum

n.a.

[Wavelength/nm(species)[ 270.866 (II) 342.848 (I) 349.811 (I) 351.433 (I) 352.138 (I) 352.349 (I) 354.775 (II)

DATA

Crystal structure (cell dimensions/pm), space group

a-Es h.c.p. p- Es f.c.c. T(a-> fi) = 1133 K X-ray diffraction: mass absorption coefficients [p/p)lcm2 g ': CuK„ n.a. MoKk n.a. Neutron scattering length, b/10"12 cm: n.a. Thermal neutron capture cross-section, M )/kJ mol'1: n.a. Ionization energies/kj mol"1:

1. M

-+ M*

•CRYSTAL

627

Electron binding energies/eV

Main lines in atomic spectrum

n.a.

[Wavelength/nm(species)] n.a.

DATA

Crystal structure (cell dimensions/pm), space group

X-ray diffraction: mass absorption coefficients (/i/p)/cm! g"1: CuKa n.a. MoKa n.a. Neutron scattering length, fc/10"12 cm: n.a. Thermal neutron capture cross-section, a,/barns: 5800 (257Fm)

•GEOLOGICAL

DATA

Minerals Not found on Earth.

Chief source: fermium-253 can be obtained in

Abundances

nanogram (10“9 g) quantities by the bombardment of 239Pu with neutrons

Sun (relative to H = 1 x 1012): n.a.

World production: about 3 x lO"6 g in total.

Earth’s crust/p.p.m.: nil Seawater/p.p.m.: nil

Specimen: commercially available, under licence

- see Key.

77

Atomic number: 9

CAS:

Relative atomic mass (l2C = 12.0000): 18.998 4032

[7782-41-4]

•CHEMICAL Description: Fluorine is a pale yellow gas (F2) and is the most reactive of all the elements. It is

also the strongest available oxidising agent. Fluorine is produced by the electrolysis of molten KF.2HF and is used to make UF6, SF6 and fluorinating agents such as C1F3. A wide range of fluorinated materials are now in common use including polymers, pesticides and antibiotics. Some fluoride salts are also used, such as CaF2 as a flux in metallurgy and A1F3 in the production of aluminium. Radii/pm: F-133; atomic 70.9; covalent 58; van der Waals 135 Electronegativity: 3.98 (Pauling); 4.10 (Allred); 10.41 eV (absolute) Effective nuclear charge: 5.20 (Slater); 5.10 (Clementi); 4.61 (Froese-Fischer)

Standard reduction potentials £"7V o

-I 2.866

F

F2 2.979

F2 ^

-hf2~

3.053

F2- HF (aq)

Oxidation states F1

[Ne]



s2p5

Covalent bonds

F" (aq), HF, KHF2, CaF2, many salts and derivatives of other elements f2

Bond r/ pm El 147 F—O F—N 137 F—F 142 For other bonds to fluorine, see other elements

kj mol1 190 272 159

Banal

•PHYSICAL Melting point/K: 53.53

AH^Jk] mol !: 5.10

Boiling point/K: 85.01

AWvap/kJ mol1: 6.548

Critical temperature/K: 144.3 Critical pressure/ kPa: 5573

Thermodynamic properties (298.15 K, 0.1 MPa) State Gas (F2) Gas (atoms)

AfJF/kJ mol1 0 78.99

ArGe/kJ mol1 0 61.91

S -+ -+ -+ -+ -> -+ ^

M* M2* M3* M4’ M5+ M7* M8+ M9t

1681 3374 6050 8408 11023 15164 17 867 92 036 106 423

Electron binding energies/eV

K

Is

696.7

Main lines in atomic spectrum

(Wavelength/nm(species)] 685.603 (I) 690.248 (I) 703.747 (I) 712.789 (I) 775.470 (I)

•CRYSTAL Crystal structure (cell dimensions/pm), space group

a-F2 monoclinic (a = 550, b = 328, c= 728, (3 = 102.17°), C2/m (3-F2 cubic (a = 667), Pm3n T{a -» p) = 45.6 K X-ray diffraction: mass absorption coefficients (p/p)/cm2 g“‘: CuK[( 16.4 MoK0 1.80 Neutron scattering length, fo/10'12 cm: 0.5654 Thermal neutron capture cross-section, M }/kJ mol-1: 44 (calc.) Ionization energies/kj mol-1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M* M2+ M3t M4* M5* M8+ M7* M8* M9’

-» -> -+ -+ -> -+ -+ -+ -» -+

400 (2100) (3100) (4100) (5700) M5* (6900) M6+ (8100) M7* M8+ (12 300) M9* (12 800) M10’ (29300) M* M2* M3+

Electron binding energies /eV

K L, Lit I« M, M„ Mm M|V Mv

Is 2s

101137 18 639 17 907 15 031 4652 4327 3663 3136 3000

2Pl/2 2P3/2

3s 3pi,2 3P3/2 3 M )/kJ mol"1: M7 M+ —> M2f M27 M3+ M3+ —> M4t M4‘ —> M5*

592. 1167 1990 4250 6249

K L, L„ I+u M, Mn Mra Mv

Is 2s 2pi/2 2p3/2 3s 3Pl« 3p3/2 3d3/2 3d5/2

50 239 8376 7930 7243 1881 1688 1544 1221.9 1189.6

Main lines in atomic spectrum

[Wavelength / nm (species)] 342.247 (II) 364.619 (II) 368.413 (I) 376.839 (II) 368.305 (I) 407.870 (I) (AA)

continued in Appendix 2, p255

•CRYSTAL Crystal structure (cell dimensions/pm), space group

a-Gd h.c.p. (a = 363.60, c= 578.26), P63/mmc /3-Gd b.c.c. (a = 405), Im3m Ha ->fl = 1535 K High pressure form: (a = 361, c= 2603), R3m X-ray diffraction: mass absorption coefficients (p/p)/cm2 g 1: CuK(( 439 MoK(; 64.4 Neutron scattering length, h/10"12 cm: 0.65 Thermal neutron capture cross-section, cr,/barns:49 000

•GEOLOGICAL

DATA

Minerals Mineral Bastnasite* Monazite*

Formula Density Hardness Crystal appearance (Ce,La, etc.)C03F 4.9 4-4.5 hex., vit/greasy yellow (Ce, La, Nd, Th, etc.)P04 5.20 5-5.5 mon., waxy/vit. yellow-brown

‘Although not a major constituent, gadolinium is present in extractable amounts. Chief ores: monazite, bastnasite World production/tonnes y"1: c. 400 Main mining areas: USA, Brazil, India, Sri Lanka,

Australia, China. Reserves/tonnes: c. 2 x 106 Specimen: available as chips, foil or ingots. Safe.

Abundances Sun (relative to H = 1 x 1012): 13.2 Earth’s crust/p.p.m.: 7.7 Seawater/p. p.m.:

Atlantic surface: 5.2 x 10"7 Atlantic deep: 9.3 x 10"7 Pacific surface: 6.0 x 10"' Pacific deep: 15 x 10“7 Residence time /years: 300 Classification: recycled Oxidation state: III 83

Atomic number: 31

CAS:

Relative atomic mass (12C = 12.0000): 69.723

17440-55-3]

•CHEMICAL Description: Gallium is a soft, silvery-white metal, and has the longest liquid range of all the

elements. It is stable in air and with water; it dissolves in acids and alkalis. Gallium has semiconductor properties, especially as gallium arsenide. It is used in light-emitting diodes and microwave equipment. Radii/pm: Ga3+ 62; Ga+113; atomic 122; covalent 125 Electronegativity: 1.81 (Pauling); 1.82 (Allred); 3.2 eV (absolute) Effective nuclear charge: 5.00 (Slater); 6.22 (Clementi); 6.72 (Froese-Fischer)

Standard reduction potentials £"7V II

III

-0.53

acid

o,

o, c. -0.45 — Ga2 -Ga

c. -0.65

Ga3 .

Oxidation states Ga1

s2

Ga" Ga111

s1 d10

Covalent bonds

Ga20, GaCl2 etc., (Ga2CL, is Ga,[Ga,,ICl4]) [Ga2Cl6]2" Ga203, Ga(OH)3, [Ga(OH2)6]3+ (aq), GaF3, Ga2Cl6, [GaCle]3"

•PHYSICAL

r/ pm Bond* 188 Ga—F 220 Ga—Cl Ga—Br 235 Ga—I 257 244 Ga—Ga *Ga' except for GaF3

El kl mof 469 354 302 327 113

DATA

Melting point /K: 302.93

AW(^on/kI mol 5.59 AW,ap/kJ mol"1: 256.1

Boiling point/K: 2676

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

A,H'-/k] mol"1 0 277.0

AfGe/kJ mol"1 0 238.9

Se/J K"1 mol"1 40.88 169.06

Cp/J K"1 mol"1 25.86 25.36

Density/kg m"3: 5907 [293 K]; 6113.6 [liquid at m.p.]

Young’s modulus/GPa: 9.81

Molar volume/cm3: 11.81

Rigidity modulus/GPa: 6.67

Thermal conductivity/W m"1 K"1: 40.6 [300 K] Coefficient of linear thermal expansion/K"1: 11.5 x 10"6 (a axis);

Bulk modulus/GPa: n.a. Poisson’s ratio/GPa: 0.47

31.5 x 10"8 (b axis); 16.5 x 10"8 (c axis) Electrical resistivity In m: 27 x 108 [273 K] varies with axis Mass magnetic susceptibility/kg"1 m3:-3.9x 10"8 (s)

•BIOLOGICAL Biological role

Levels in humans

None, but gallium acts to stimulate metabolism.

Blood/mg

Toxic intake: < 15 mg kg"' tolerated without

dm"3: M”)/kJ mol-': c. 30 Ionization energies/kj mol”1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M+ M2+ M3t M4t M5t

—> —> -> —> —»

M7t —> M8* M9* ->

M+ M2+ M3+ M4* M5+ M6" M7+ M8+ m9+ M10+

Electron binding energies /eV

578.8 1979 2963 6200 (8700) (11400) (14 400) (17 700) (22300) (26 100)

•CRYSTAL

K L, Ln Liu M, M„ Mm MIV Mv

Is 2s 2pira 2P3/2 3s 3pi,2 3P3/2 3d3/2 3d5/2

Main lines in atomic spectrum

[Wavelength/nm(species)] 287.424 (I) (AA) 294.364 (I) 403.299 d) 417.204 (I) 639.656 (I) 641.344(1)

10 367 1299.0 1143.2 1116.4 159.5 103.5 100.0 18.7 18.7

DAT

Crystal structure (cell dimensions/pm), space group

or-Ga orthorhombic (a = 451.86, b= 765.70, c = 452.58), Cmca /3-Ga orthorhombic (a = 290, b= 813, c= 317), Cmcm (metastable form) y-Ga orthorhombic (a= 1060, b = 1356, c= 519), Cmc2! T{y->a) = 238 K High pressure form: (a = 279, c = 438), I4/mmm X-ray diffraction: mass absorption coefficients (p/p)/cm2 g”1: CuKa 67.9 MoKa 60.1 Neutron scattering length, bl\0n cm: 0.7288 Thermal neutron capture cross-section, a./barns: 2.9

•GEOLOGICAL Minerals Gallium minerals are rare, but gallium occurs in other ores to the extent of 1%. Mineral Gallite

Formula CuGaS2

Density 4.40 (calc.)

Hardness 3-3.5

Crystal appearance tet., met. grey

The ores diaspore, sphalerite, germanite and bauxite contain traces of gallium. Coal can also have a high gallium content. Chief ores: gallium is recovered as a by-product

Abundances

of zinc and copper refining.

Sun (relative to H = 1 x 1012): 631

World production/tonnes y‘:30 Main mining areas: see copper and zinc.

Reserves/tonnes: n.a. Specimen: available as ingot, and as ultrapure

Earth’s crust/p.p.m.: 18 Seawater/p.p.m.: 3 x 10~5 Residence time /years: 10 000 Classification: n.a. Oxidation state: III

gallium. Safe.

85

CAS:

Atomic number: 32

[7440-56-4]

Relative atomic mass (12C = 12.0000): 72.61

•CHEMICAL

DATA

Description: Ultrapure germanium is a silvery-white brittle metalloid element. It is stable in

air and water, is unaffected by acids, except HN03, and alkalis. It is used in semiconductors, alloys and special glasses for infrared devices. Radii/pm: Ge2+ 90; Ge4" 272; atomic 123; covalent 122 Electronegativity: 2.01 (Pauling); 2.02 (Allred); 4.6 eV (absolute) Effective nuclear charge: 5.65 (Slater); 6.78 (Clementi); 7.92 (Froese-Fischer)

Standard reduction potentials ElV IV

acid

Ge02 Ge4+

0

II -0.370

0.00

GeO Ge2+

0.255

Ge

-IV -0.29

GeH4

-0.247

(basic solutions contain many different forms]

Oxidation states

Covalent bonds

Ge" GeIV

Bond Ge—H Ge—C Ge—O Ge—F Ge—Cl Ge—Br Ge—Ge

s2 d10

GeO, GeS, GeF2, GeCl2 etc. Ge02, GeH4 etc., GeF4, GeCl, etc., [GeFfi]2", [GeClJ2", GeS2, [Ge(OH)30[- (aq)

PHYSICAL

r / pm 153 194 165 168 210 230 241

El kj mol 288 237 363 452 188 276 188

DATA

Melting point/K: 1210.6

/k] mol ': 34.7 AW,ap/kJ mol"1: 334.3

Boiling point/K: 3103

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

Ar/7' /kJ mol"1 0 376.6

AtG®/kJ mol"1 0 335.9

Se/J K 1 mol"1 31.09 167.900

C„/J K 1 mol"1 23.347 30.731

Density/kg m"3: 5323 [293 K]; 5490 [liquid at m.p.]

Young’s modulus/GPa: 79.9

Molar volume/cm3: 13.64

Rigidity modulus/GPa: 29.6

Thermal conductivity/W m"1 K"1: 59.9 [300 K] Coefficient of linear thermal expansion/K ': 5.57 x 104 Electrical resistivity In m: 0.46 [295 K] Mass magnetic susceptibility/kg"1 m3: -1.328 x 10"9 (s)

Bulk modulus/GPa: n.a. Poisson’s ratio/GPa: 0.32

• BIOLOGICAL Biological role

Levels in humans

None, but germanium acts to stimulate metabolism.

Blood /mg

Toxic intake: germanium salts generally have

dm"3: c. 0.44 n.a. Liver/p.p.m.: 0.15 Muscle/p.p.m.: 0.14 Daily dietary intake: 0.4 — 1.5 mg

low toxicity

Total mass of element

Lethal intake: LD50 (various, ingestion, rats

in average (70 kg) person:

Toxicity

etc.) = 500 - 5000 mg kg"1

Hazards The fumes of GeCl, liquid can irritate the eyes and lungs.

86

Bone/p.p.m.:

5 mg

Discovered in 1886 by C.A. Winkler at Freiberg, Germany.

Germanium

[Latin, Germania = Germany) French, germanium-, German, Germanium; Italian, germanio; Spanish, germanio

•NUCLEAR

[jer-may-niuhm)

DA

Number of isotopes (including nuclear isomers): 24

Isotope mass range: 64 -> 83

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin I

70Ge

69.924 249 7

20.5

0+

72Ge

71.922 0789

27.4

0+

73Ge

72.923 462 6

7.8

Nuclear magnetic Uses moment n E E

9/2+

-0.879 4669

73.9211774 36.5 74Ge 0+ 75.921 401 6 7.8 0+ 7r’Ge A table of radioactive isotopes is given in Appendix 1, on p241.

E, NMR E E

NMR [Reference: Ge(CH3)4] Relative sensitivity (1H = 1.00)

1.4 xl0~3 0.617 -0.9331 xlO7 -0.173 x 10'28 3.488

Receptivity (13C = 1.00) Magnetogyric ratio /rad T'1s'1 Nuclear quadrupole moment/m2 Frequency (’H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

DATA

Ground state electron configuration: [Ar]3d104s24p2 Term symbol: 3P0 Electron affinity (M -> M")/kJ mol"1: 116 Ionization energies/kj mol1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M+ M2+ M37 M47 M5+ M67 M7+ M87 M97

—> M7 —> M27 M37 —> M47 —> M57 -> M67 —> M77 —> M87 -> M97 —> M'°7

762.1 1537 3302 4410 9020 (11900) (15 000) (18200) (21 800) (27 000)

Electron binding energies/eV

K L, Lu Lin M, Mu MIU M[v Mv

Is 2s 2PU2 2P3/2 3s 3Pl/2 3p3,2 3d3/2 3d5/2

Main lines in atomic spectrum

[Wavelength/nm(species)[ 204.171 (I) 206.866 (I) 209.426 (I) 259.253 (I) 265.117 (I) 265.157 (I) (AA)

11103 1414.6 1248.1 1217.0 180.1 124.9 120.8 29.8 29.2

•CRYSTAL Crystal structure (cell dimensions/pm), space group

Cubic (a = 565.754), Fd3m, diamond structure High pressure forms: (a = 488.4, c= 269.2), 14,/amd; [a = 593, c= 698), P432,2; (a = 692), b.c.c. X-ray diffraction: mass absorption coefficients (/i/p)/cm2 g ': CuK„ 75.6 MoK„ 64.8 Neutron scattering length, h/10~12 cm: 0.8193 Thermal neutron capture cross-section, cra/barns:2.2

•GEOLOGICAL Minerals Mineral Germanite

Formula Cu26Fe4Ge4S32

Density 4.46

Hardness 4

Crystal appearance cub, met. pale greyish-pink

Chief ores: not mined as such; widely distributed

Abundances

in other minerals and Ge is recovered as a by-product of zinc and copper refining.

Sun (relative to H = 1 x 1012): 3160

World production/tonnes y1: 80 Main mining areas: see zinc and copper. Reserves/tonnes: n.a. Specimen: available as chips, pieces or powder.

Safe.

Earth’s crust/p.p.m.: 1.8 Seawater/p. p.m.:

Atlantic surface: 0.07 x lO-8 Atlantic deep: 0.14 x 10"6 Pacific surface: 0.35 x lO^6 Pacific deep: 7.00 x 10~* Residence time/years: 20 000 Classification: recycled Oxidation state: IV

87

Atomic number: 79 Relative atomic mass (12C = 12.0000): 196.96654

•CHEMICAL

CAS: [7440-57-5]

DATA

Description: Gold is a soft metal with a characteristic shiny yellow colour. It has the highest malleability and ductility of any element, and can be beaten into a film only microns thick. Gold is unaffected by air, water, acids (except aqua regia, HN03-HC1) and alkalis. It is used as bullion, in jewellery, electronics and glass, to colour it and as a heat reflector. Radii/pm: Au3+ 91; Au+137; atomic 144; covalent 134 Electronegativity: 2.54 (Pauling); 1.42 (Allred); 5.77 eV (absolute) Effective nuclear charge: 4.20 (Slater); 10.94 (Clementi); 15.94 (Froese-Fischer)

Standard reduction potentials £"7V III

I 1.52

3+

1.36

1.83

All*

Au'

Au

1.002 0.926

acid

_

1.154

1

[AuC14] -[AuC12]-Au 0.636 0.623

0.662

Au

[Au(SCN)4]--[Au(SCN)2l

Oxidation states Au 1 Au° Au1

d10s2 di(y d10

Au11

d9

[Au(NH3)J- in liquid ammonia Gold clusters e.g. [Au8(PPh3)8]2+ Au2S, [Au(CN)2]- and other complexes Rare but some complexes known

•PHYSICAL

Au111 d8

Auv d6 Au191 d4

Au203, [Au(OH)4]- (aq), [AuC14]- (aq), [AuC13(OH)]- (aq), Au2S3, AuF3, Au2C1s, AuBr3, complexes AuF5 AuF7

DATA

Melting point/K: 1337.58 Boiling point/K: 3080

AW^/kJ mol-1: 12.7 AWvap/kJ mol-1: 324.4

Thermodynamic properties (298.15 K, o.i MPa) State Solid Gas

AfJP/kJ mol-1 0 336.1

AtG‘7kI mol-1 0 326.3

Density/kg m-3: 19 320 [293 K]; 17 280 [liquid at m.p.] Molar volume/cm3: 10.19 Thermal conductivity/W m-1 K-1: 317 [300 K] Coefficient of linear thermal expansion /K-1:14.16 x 10-6 Electrical resistivity/n m: 2.35 x 10-8 [293 K] Mass magnetic susceptibility/kg-1 m3: -1.78 x 10-9 (s)

S9/J K 1 mol1 47.40 180.503

C„/J K-1 mol1 25.418 20.786

Young’s modulus/GPa: 78.5 Rigidity modulus/GPa: 26.0 Bulk modulus/GPa: 171 Poisson’s ratio/GPa: 0.42

•BIOLOGICAL Biological role

Levels in humans

None, but acts to stimulate metabolism.

Blood/mg dm-3: (0.1 -4.2) Bone/p.p.m.: 0.016 Liver/p.p.m.: 0.0004 Muscle/p.p.m.: n.a.

Toxicity Toxic intake: gold metal and gold salts generally have low toxicity Lethal intake: n.a.

Hazards Gold is poorly absorbed by the body and poisoning by gold compounds is very rare. Gold-based anti-arthritics can cause liver damage and kidney damage.

88

Daily dietary intake:

x

10-4

n.a., but very low

Total mass of element in average (70 kg) person:

0.2 mg

Known to ancient civilizations.

Gold

[Anglo-Saxon, gold; Latin, aurum] French, or; German, Gold; Italian, oro; Spanish, oro

•NUCLEAR

Igowld]

DATA

Number of isotopes (including nuclear isomers): 39

Isotope mass range: 176 -> 204

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin /

197Au 196.966543 100 3/2+ A table of radioactive isotopes is given in Appendix 1, on p241.

+0.148159

NMR

197Au 2.51 x 10'5 0.06 0.357 xlO7 0.547x1 O'28 1.712

NMR [Difficult to detect] Relative sensitivity (*H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T'1s_1 Nuclear quadrupole moment /m2 Frequency (‘H = 100 Hz; 2.3488T)/MHz

•ELECTRON

Nuclear magnetic Uses moment u

SHELL

Ground state electron configuration: [Xe]4f145d106s1 Term symbol: 2S1/2 Electron affinity (M -> M")/kJ mol‘: 222.8 Ionization energies/kj mol 1:

1. 2. 3. 4, 5. 6. 7. 8. 9. 10.

890.0 M M+ 1980 M+ M2+ (2900) M2+ -> M3+ (4200) M3+ —» M4+ (5600) -» M5t (7000) M5+ -> M6+ (9300) M6’ —> M7+ M7* —> M8+ (11000) M8t -> M9t (12 800) (14 800) —> Ml0+

Electron binding energies / eV

K L, Ln 1+n M, M„ Mb, Mw Mv

Is 2s 2Pl/2 2P3/2 3s 3Pl/2 3P3/2 3d3/2 3d5/2

Main lines in atomic spectrum

[Wavelength/nmfspecies)]

80 725 14 353 13 734 11919 3425 3148 2743 2291 2206

201.200 (I)

202.138 (I) 242.795 (I) (AA) 267.595 (I) 274.825 (I) 312.278(1)

continued in Appendix 2, p256

•CRYSTAL Crystal structure (cell dimensions/pm), space group

f.c.c. {a = 407.833), Fm3m X-ray diffraction: mass absorption coefficients {/u/p)lcm2 g *: CuKa 208 MoK[; 115 Neutron scattering length, bl\0~'2 cm: 0.763 Thermal neutron capture cross-section, a a/barns: 98.7

•GEOLOGICAL Minerals Gold occurs mainly as the metal, occasionally as crystals, but more generally as grains, sheets and flakes in other rocks. Mineral Gold Sylvanite

Formula Au AgAuTe,

Density 19.3 8.16

Hardness 2.5-3 1.5-2

Chief ores: quartz veins in extrusive rocks World production/tonnes y~‘: c. 1400 Main mining areas: South Africa, USA, Canada,

Russia.

Crystal appearance cub., met. white hex., met. white

Abundances Sun (relative to H = 1 x 10'2): 5.6 Earth’s crust/p.p.m.: 0.0011 Seawater/p.p.m.: 1 x 10'5 Residence time/years: n.a.

Reserves/tonnes: 15 000

Classification: n.a.

Specimen: available as foil, powder, rod, shot,

Oxidation state: I

sponge or wire. Safe.

89

Atomic number: 72 Relative atomic mass (I2C = 12.0000): 178.49

• CHEMICAL

m

CAS: [7440-58-6]

DATA

Description: Hafnium is a lustrous, silvery, ductile metal that resists corrosion due to an

oxide film on its surface. However, powdered hafnium will burn in air. The metal is unaffected by acids (except HF) and alkalis. It is used in control rods for nuclear reactors, and in high temperature alloys and ceramics. Radii/pm: Hf3* 84; atomic 156; covalent 144 Electronegativity: 1.3 (Pauling); 1.23 (Allred); 3.8 eV (absolute) Effective nuclear charge: 3.15 (Slater); 9.16 (Clementi); 13.27 (Froese-Fischer)

Standard reduction potentials ElV IV

Hf4"1 Hf02

0

_L70 - Hf -1.57

- Hf

Oxidation states Hf Hf1' Hfn Hr

d3 d2 d1 d°[f14]

HfCl ? HfCl2 ? HfCl3, HfBr3, Hfl3, Hf3* reduces water HfOz, Hf(OH)3* (aq), HfF„ HfCL, etc., [HfF6]2-, [HfF7]3-, [HfFJ4-

Melting point/K: 2503

Atf^/kJ mol h 25.5

Boiling point/K: 5470

A//vap/kJ moT1: 661.1

Thermodynamic properties (298.15 K, o.l MPa) State Solid Gas

AtH*7kJ mol1 0 619.2

AfGe/kJ mol1 0 576.5

SVJ K1 mol1 43.56 186.892

C„/J K 1 mol"1 25.73 20.803

Density/kg m 3: 13 310 [293 K]; 12 000 [liquid at m.p.]

Young’s modulus/GPa: 141

Molar volume / cm3: 13.41

Rigidity modulus/GPa: 56

Thermal conductivity/W m"1 K"1: 23.0 [300 K]

Bulk modulus/GPa: 109

Coefficient of linear thermal expansion/K 1:5.9 x 10 6

Poisson’s ratio/GPa: 0.26

Electrical resistivity In m: 35.1

x

10"8 [293 K]

Mass magnetic susceptibility/kg 1 m3: +5.3 x 10 3 (s)

•BIOLOGICAL

DATA

Biological role

Levels in humans

None.

Organs:

Toxicity

Daily dietary intake:

Toxic intake: hafnium and hafnium salts

generally have low toxicity Lethal intake: LD50 (chloride, oral, rat) = 2400 mg kg"'

Hazards Hafnium is poorly absorbed by the body and poisoning by hafnium compounds is very rare.

90

n.a. n.a.

Total mass of element in average (70 kg) person:

n.a.

Discovered in 1923 by D. Coster and G.C. von Hevesey at Copenhagen, Denmark.

Hafnium

[Latin, Hafnia = Copenhagen] French, hafnium; German, Hafnium; Italian, afnio; Spanish, hafnia

[haf-ni-uhm]

•NUCLEAR Number of isotopes (including nuclear isomers): 33

Isotope mass range: 158 -+ 184

Key isotopes Nuclide

Atomic mass

174Hf

173.940 044

0.162

0+

E

176Hf

175.941406

5.206

0+

E

177Hf

176.943217

18.606

7/2+

l78Hf

177.943 696

27.297

0+

Natural abundance (%)

Nuclear spin I

+0.7936

177Hf 6.38 x 10"1 0.88 +0.945 x 107 +3.365 x 1031 3.120

Relative sensitivity ('H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio /rad T ' s'1 Nuclear quadrupole moment/m2 Frequency (’H = 100 Hz; 2.3488T)/MHz

|



E L E C T R 0 N

S H E L L

E E

178.945 812 13.629 9/2+ ,79Hf 179.946 545 35.100 0+ »Hf A table of radioactive isotopes is given in Appendix I, on p241.

NMR [Difficult to observe]

Nuclear magnetic Uses moment p

-0.6409

E, NMR E

179Hf 2.16 x 10-4 0.27 -0.609 x 107 +3.793 x 10“31 1.869

D A T A

.

Ground state electron configuration: [Xe]4fw5d26s2 Term symbol: 3F2 Electron affinity (M -> M )/kJ mol1: c. 0

1. 2. 3. 4. 5.

M M+ M2t M3+ M4+

-» •■> -+ -+ ->

M+ M2+ M3+ M4+ M5+

Main lines in atomic spectrum

Electron binding energies /eV

Ionization energies/kj mol ’:

642 1440 2250 3216 6596

K L, Lh Liu

M, M„ Mm

Mw M,

Is 2s 2p m 2p3/2 3s 3Pl/2 3p3/2 3d3/2 3d3/2

[Wavelength/nm(species)] 201.278 (II) 202.818 (II) 286.637 (I) 289.826 (I) 307.288 (I) (AA) 329.980 (II) 368.224 a)

65 351 11271 10 739 9561 2601 2365 2107 1716 1662

continued in Appendix 2, p256

•CRYSTAL

DATA

Crystal structure (cell dimensions/pm), space group

o-Hf h.c.p. (a = 319.46, c= 505.10), P63/mmc /3-Hf cubic (a = 362) 3) = 2033 K X-ray diffraction: mass absorption coefficients

cm2 g 1: CuK, 159 MoKa 91.7

Neutron scattering length, bl 10 12 cm: 0.777 Thermal neutron capture cross-section, rra/barns: 104

•GEOLOGICAL

DATA

Minerals Extremely rare. Hafnium generally occurs as a 1-5% impurity in zirconium minerals. Mineral Hafnon

Formula HfSi04

Density 6.97

Hardness n.a.

Crystal appearance tet.

Chief source: hafnium is obtained as a by-product

Abundances

of zirconium refining

Sun (relative to H = 1

World production/tonnes y 1: c. 50 Main mining areas: see zirconium.

x

1012): 6

Earth’s crust/p.p.m.: 5.3 Seawater/p.p.m.: 7 x 10”6 Residence time /years: n.a.

Reserves/tonnes: n.a.

Classification: n.a.

Specimen: available as foil, pieces, powder,

Oxidation state: IV

sponge or wire. Safe.

91

o [54037-

•Vl

Atomic number: 108 Relative atomic mass (l2C= 12.0000): (265)

• CHEMICAL Description: Hassium is a radioactive metal which does not occur naturally, and is of research

interest only. Radii/pm: Hs4+ 80 (est.); atomic 126 (est.) Electronegativity: n.a. Effective nuclear charge: n.a.

Standard reduction potentials F7V IV

0 +0.4 (est.)

Hs

Hs4+

Oxidation states Hs1 Hs11 Hsm Hsw Hsv Hs''1 HsV11

d6 d5 d4 d3 d2 d1 [fi4j

predicted predicted predicted, most stable? predicted predicted predicted predicted

Melting point/K: n.a.

AW fusion/kj mol-1: n.a. AWvap/kJ mol-1: n.a. AWsubi /kj mol-1: 628 (est.)

Boiling point/K: n.a.

Thermodynamic properties (298.15 K, o.l MPa) State Solid Gas

AfH*lk] mol-1 0 n.a.

AfG*7kJ mol-1 0 n.a.

S*/J K-1 mol-1 n.a. n.a.

Density/kg m-3: 41 000 (est.) Molar volume/cm3: n.a. Thermal conductivity/W m-1 K-1: n.a. Coefficient of linear thermal expansion/K-1: n.a. Electrical resistivity/a m: n.a. Mass magnetic susceptibility/kg-1 m3: n.a.

•BIOLOGICAL Biological role

Levels in humans

None.

nil

Toxicity Toxic intake: n.a. Lethal intake: n.a.

Hazards Hassium is never encountered normally, and only a few atoms have ever been made. It would be dangerous because of its intense radioactivity.

92

Daily dietary intake:

nil

Total mass of element in average (70 kg) person:

nil

C„/J K-1 mol-1 n.a. n.a.

®8

PI ». .

Discovery: see Nuclear Data section. [Latin Hassias = Hesse, the German state]

Hassium

French, hassium; German, Hassium; Italian, hassio; Spanish, hassio

_

(hass-iuhml

Discovery: Hassium was first made in 1984 by Peter Armbruster, Gottfried Miinzenberg and

their co-workers at Gesellschaft fiir Schwerionenforschung in Darmstadt, Germany. Number of isotopes (including nuclear isomers): 3

Isotope mass range: 263 —> 265

Key isotopes Nuclide

Atomic mass Half life (T l/z) Decay mode and energy (MeV)

2«Hs

264.129

c. 8 x 105 s

a, SF

265Hs

264.129

c.2xl0'3s

a

Nuclear Nucl. mag. Uses spin l moment u

NMR [Not recorded]

•ELECTRON' SHELL

DATA

Ground state electron configuration: [Rn]5f146d67s2 Term symbol: 5D4 Electron affinity (M -> M")/kJ mol'1: n.a. Ionization energies/kj mol'1:

1. M

^ M+

750 (est.)

Electron binding energies/eV

Main lines in atomic spectrum

n.a.

[Wavelength/nm(species)] n.a.

•CRYSTAL Crystal structure (cell dimensions/pm), space group

X-ray diffraction: mass absorption coefficients (p/p)/cm2 g'1: CuK„ n.a. MoK„ n.a. Neutron scattering length, b/10'12 cm: n.a. Thermal neutron capture cross-section, a,/bams: n.a.

•GEOLOGICAL Minerals Not found on Earth.

Chief source: hassium has been made by the

Abundances

so-called cold fusion method, in which a target Sun (relative to H = 1 x 1012): n.a. Earth’s crust/p.p.m.: nil of lead was bombarded with atoms of iron to give an atom of hassium: 208Pb + 58Fe -» 265Hs + n Seawater/p.p.m.: nil Specimen: not available commercially.

93

He

Atomic number: 2 Relative atomic mass (l3C = 12.0000): 4.002602

CAS: [7440-59-7]

Discovery: Helium was observed in the sun’s spectrum during the eclipse of 1868 by

Norman Lockyer and Edward Frankland. Isolated in 1895 by Sir William Ramsey at London, England and independently by P.T. Cleve and N.A. Langlet at Uppsala, Sweden. Description: Helium is a colourless, odourless gas obtained mainly from gas wells. It is inert towards all other elements and chemicals. Helium is used in deep-sea diving, weather balloons, and as a liquid for low-temperature research instruments. Radii/pm: atomic 128; van der Waals 122 Electronegativity: n.a. (Pauling); 5.50 (Allred); [12.3 eV (absolute) - see Key] Effective nuclear charge: 1.70 (Slater); 1.69 (Clementi); 1.62 (Froese-Fischer)

Oxidation states

Covalent bonds

He0

none

[He]

only He1 as a gas

•PHYSICAL Melting point/K: 0.95 (under pressure)

AWf^/kJ mol-1: 0.021 AW,ap/kJ mol-1: 0.082

Boiling point/K: 4.216 Critical temperature/K: 5.25 Critical pressure/ kPa: 229

Thermodynamic properties (298.15 K, o.l MPa) State Gas

A(He/kJ mol-1 0

AfG*/kJ mol-1 0

Sp)= just below melting point High pressure form: (a = 334, c = 2 410), R3m X-ray diffraction: mass absorption coefficients (p/p)/cm2 g"1: CuK„ 128 MoKtl 73.9 Neutron scattering length, b/1012 cm: 0.808 Thermal neutron capture cross-section, 3

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin I

Nuclear magnetic Uses moment p

■H

1.007 825 035

99.985

1/2

+2.792 845 6

NMR

2H

2.014 101 779

0.015

1

+0.857437 6

NMR

3H*

3.01605

0

1/2

+2.97896

R, D

*3H is radioactive with

a half-life of 12.26 v and

decay mode

{0.01861 MeV); no y.

‘H 1.00 (by def.) 5680 26.7510 xlO7 100.000

NMR [Reference: Si(CH3)4] Relative sensitivity (: I I = 1.00) Receptivity (13C= 1.00) Magnetogyric ratio/rad T"ls_1 Nuclear quadrupole moment/m2 Frequency (‘H = 100 Hz; 2.3488T)/MHz

•ELECTRON

B

2H 9.65 xlO3 8.2 x 10 3 4.1064 x 107 2.860 x 10~31 15.351

3H 1.21 28.5335 x 10' 106.663

SHELL

Ground state electron configuration: Is1 Term symbol: 2S1/2 Electron affinity (M -> M~)/kJ mol1: 72.8 Ionization energies/kj mol ':

1. M

^ M+

1312.0

Electron binding energies/eV

Main lines in atomic spectrum

K

[Wavelength / nm (species) ] 434.047 (I) 486.133 (I) 656.272 (I) 656.285 (I) 1875.10(1)

Is

13.6

•CRYSTAL Crystal structure (cell dimensions/pm), space group

H2 h.c.p. (a = 377.6, c= 616.2), P63/mmc 2H, h.c.p. (a = 360.0, c= 585.8), P63/mmc H2 cubic (a= 533.8), Fm3m 2H2 cubic (a = 509.2), Fm3m H2 tetragonal (a = 450, c = 368), 14 2H2 tetragonal (a = 338, c = 560), 14 T (h.c.p. -> tetragaonal) = 4.5 K X-ray diffraction: mass absorption coefficients (p/p)lcm2 g ': CuKa 0.435 MoK„ 0.380 Neutron scattering length, h/10 12 cm: -0.37390 Thermal neutron capture cross-section, aa/barns: 0.3326

• GEOLOGICAL Minerals None as such, although hydrogen is present in many as water molecules

Sources: Hydrogen gas is produced mainly from

Abundances

natural methane gas (CII, + 2H20 = 3H2 + CO). Some is also produced from the electrolysis of brine using a mercury amalgam cell, or by the action of steam on red hot coke which gives a mixture of H2 and CO.

Sun (relative to H = 1 x 1012): most

World production /m3 y"1: 350 x 109 (hydrogen gas) Reserves/tonnes: almost limitless Specimen: available in small pressurized

canisters. Warning!

abundant element, and taken as standard against which others are measured. Earth’s crust/p.p.m.: 1520 Atmosphere/p.p.m. (volume): 0.5 Seawater/p.p.m.: constituent of water;

some dissolved H2 gas. Residence time/years: n.a. Oxidation state: I

99

Atomic number: 49 Relative atomic mass (12C= 12.0000): 114.818

CAS: [7440-74-6]

•CHE M ICALDATA Discovery: Indium was discovered in 1863 by Ferdinand Reich and Hieronymous Richter at

Freiberg, Germany. Description: Indium is a soft, silvery-white metal, and has one of the longest liquid range of all the elements. It is stable in air and with water; it dissolves in acids. Indium is used in low-melting alloys in safety devices. Indium arsenide and indium antimonide have uses in transistors and thermistors. Radii/pm: In3* 92; In* 132; atomic 163; covalent 150 Electronegativity; 1.78 (Pauling); 1.49 (Allred); 3.1 eV (absolute) Effective nuclear charge: 5.00 (Slater); 8.47 (Clementi); 9.66 (Froese-Fischer)

Standard reduction potentials E /V III

acid

In

3+

-0-444

In+

-0.126

In

-0.3382

Oxidation states

Covalent bonds

In' In" In111

Bond In—H In—C In—O In'—F In1—Cl In'—Br In—In

s2 s1 d10

InCl, InBr, Ini [In2Cl,s]2-, [In2Br6]2", [In2I6]2 ln203, In(OH)3, [In(OH2)6]3* (aq), InF3, InCl3 etc., [InCl5]2", [InCl6]3", complexes

•PHYSICAL

r/ pm 185 216 213 199 240 254 325

E/ kj mol' 243 165 109 523 435 406 100

DAT

Melting point/K: 429.32

AWf^/kJ mol"1: 3.27 AWvap/kJ mol"1: 226.4

Boiling point /K: 2353

Thermodynamic properties (298.15 K, 0.1 MPa) State

Af//*7kJ mol'1

AfG*7kJ mol"1

S*/J K"1 mol"1

C„/J K 1 mol"1

Solid Gas

0 243.30

0 208.71

57.82 173.79

26.74 20.84

Density/kg m"3: 7310 [298 K]; 7032 [liquid at m.p.]

Young’s modulus/GPa: 10.6

Molar volume/cm3: 15.71

Rigidity modulus/GPa: 3.68

Thermal conductivity/W m"1 K“': 81.6 [300 K] Coefficient of linear thermal expansion/K"1:33 x 10"6 Electrical resistivity In m: 8.37 x 10“8 [293 K] Mass magnetic susceptibility/kg"1 m3:-7.0x 10"9 (s)

Bulk modulus/GPa: n.a.

•BIOLOGICAL

Poisson’s ratio/GPa: 0.45

DATA

Biological role

Levels in humans

None, but acts to stimulate metabolism.

Blood/mg dm"3: n.a. but low Bone/p.p.m.: n.a.

Toxicity Toxic intake: 30 mg Lethal intake: LD50 (sulfate, oral, rat) =

c. 1200 mg kg"1

Hazards Indium is moderately toxic by ingestion and affects the liver, heart and kidneys. It may have teratogenic effects.

100

Liver/p.p.m.: n.a Muscle/p.p.m.: c. 0.015 Daily dietary intake: n.a. but low Total mass of element in average (70 kg) person: C.

0.4 mg

Discovery: see Chemical Data section. (Named after the indigo line in its spectrum]

Indium

French, indium; German, Indium-, Italian, indio; Spanish, indio

[in-di-uhm)

•NUCLEAR

DATA

Number of isotopes (including nuclear isomers): 59

Isotope mass range: 102 -» 132

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin I

Nuclear magnetic Uses moment fi

ll3In

112.904 061

4.3

9/2+

+5.5289

"5In*

114.903 882

95.7

9/2+

+5.5408

* "5In is radioactive with a half-life of 6 x 10H y and decay mode p" (0.496 MeV); no A table of radioactive isotopes is given in Appendix 1, on p242.

Nuclear quadrupole moment/nr

U3In 0.345 83.8 5.8493 xlO7 +0.799 x 10”28

Frequency ('H = 100 Hz; 2.3488T)/MHz

21.866

NMR [Reference: In3+ (aq)] Relative sensitivity ('H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T_1s_1

•ELECTRON

SHELL

E, NMR E, NMR

y.

113In 0.348 1890 5.8618 xlO7 +0.810 xlO”28 21.914

DATA

Ground state electron configuration: [Kr]4d105s25p' Term symbol: 2P1/2 Electron affinity (M -> M )/kJ mol”1: c. 30 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M —> M+ M* —> M2* M3* M2* M3t —> M4+ M4* -> M5+ M5+ -> M6+ M6* -> M7+ M7+ M8+ M9-’ Ms+ M9+ —> M10’

Main lines in atomic spectrum

Electron binding energies /eV

Ionization energies/kj mol 1:

558.3 1820.6 2704 5200 (7400) (9500) (11 700) (13 900) (17 200) (19 700)

K L, U bra M, M,i M,„ M1V Mv

Is 2s 2pi/2 2p3/2 3s 3Pl/2 3P3/2 3d3/2 3d5/2

[Wavelength/nm(species)] 303.936 (I) CM) 325.609 (1) 325.856 (I) 410.176(1) 451.131 (I)

27 940 4238 3938 3730 827.2 703.2 665.3 451.4 443.9

continued in Appendix 2, p256

•CRYSTAL Crystal structure (cell dimensions/pm), space group

face centred tetragonal (a = 325.30, c = 494.55), I4/mmm X-ray diffraction: mass absorption coefficients (p/p)/cm2 g Neutron scattering length, b/10”12 cm: 0.4065 Thermal neutron capture cross-section, a,/barns: 194

•GEOLOGICAL

CuKa 243 MoK„ 29.3

DATA

Minerals Indium has been reported to occur as the native element, but it mainly occurs in zinc sulfide and lead sulfide ores to the extent of 1%. Mineral Indite

Formula FeIn2S„

Density 4.67

Hardness 4.5

Crystal appearance cub., met. white

Chief ores: it is obtained as a by-product of zinc

Abundances

and lead smelting.

Sun (relative to H = 1 x 1012): 44.7

World production /tonnes y_l: 75

Earth’s crust/p.p.m.: 0.049

Main mining areas: see zinc and lead.

Seawater/p.p.m.: 1 x 10”7 Residence time /years: n.a.

Reserves/tonnes: > 1500

Classification: n.a.

Specimen: available as foil, granules, pieces,

Oxidation state: III

powder, rod, shot or wire. Care!

101

Atomic number: 53 Relative atomic mass (12C= 12.0000): 126.90447

• CHEMICAL

CAS: [7553-56-2]

DATA

Description: Iodine is a black, shiny, non-metallic solid (I2) which sublimes easily on heating

to give a purple vapour. It is used as a disinfectant, in pharmaceuticals, food supplements, dyes, catalysts, and photography. Radii/pm: I" 196; covalent 133; van der Waals 215 Electronegativity: 2.66 (Pauling); 2.21 (Allred); 6.76 eV (absolute) Effective nuclear charge: 7.60 (Slater); 11.61 (Clementi); 14.59 (Froese-Fischer)

Standard reduction potentials jET7V -I

I

VII

1.20 1.60

acid

H3IOs-I03

_

1.13 1.44 -HIO-I2 1.21

IClo

0.535

1.07 0.26

0.65

h3io6

base

IOo

0.15

icr

0.42

0.535

I? l2

1

0.48

Oxidation states I-' 1°

I' 1“ f jVII

[Xe] s2p5 s2p4 s2p2 s2 d10

Covalent bonds

I- (aq), HI, KI, etc. I2,13-, I5~, etc. I„+, IC12 , etc. I409 (=T+(I03-)3),IC13 I205, HI03,103“ (aq), IFs, IF6H5I06, HJ06- (aq) etc., HIO„ I04- (aq), IF7

r/ pm 161 214 195 191 232 267

Bond I—H I—C I—O I—F 1—Cl I—I

E/ kj mol' 295 213 201

278 208 149

For other bonds to iodine: see other elements

•PHYSICAL

DAT

Melting point /K: 386.7

AW^^/kJ mol1: 15.27

Boiling point/K: 457.50

AWvap/kJ mol-1: 41.67

Critical temperature/K: 819

Thermodynamic properties (298.15 K, o.i MPa) State Solid Gas (I2) Gas (atoms)

Af/CTkJ mol 1 0

62.438 106.838

AfG®/kJ mol-1 0

19.327 70.250

SVJ K-1 mol-' 116.135 260.69 180.791

C„/J K 1 mol 54.438 36.90 20.786

Density/kg m-3: 4930 [293 K] Molar volume/cm3: 25.74 Thermal conductivity/W m-1 K-1: 0.449 [300 K] Coefficient of linear thermal expansion/K-1: n.a. Electrical resistivity IQ m: 1.37 x 107 [293 K] Mass magnetic susceptibility/kg 1 m3:^.40x 10-9 (s)

•BIOLOGICAL Biological role

Levels in humans

Most iodine exists in nature as iodide ions, I-, the form in which it is taken into our bodies. Iodine is essential to many species, including humans.

Blood/mg dm

Toxicity Toxic intake: 2 mg as I2. Iodides are similar in

toxicity to bromides. Lethal intake: human, oral = 2 g as I2.

LD50 (Nal, oral, rat) = 14 000 mg kg 1

Hazards Iodine in its elemental form, I2, is toxic, and its vapour irritates the eyes and lungs. The maximum allowable concentration when working with iodine is 1 mg m-3 in air.

102

3:0.057 0.27 Liver/p.p.m.: 0.7 Muscle/p.p.m.: 0.05 - 0.5 Daily dietary intake: 0.1 — 0.2 mg Bone/p.p.m.:

Total mass of element in average (70 kgl person:

12-20 mg

Discovered in 1811 by Bernard Courtois at Dijon, France

Iodine

[Greek, iodes = violetl French, iode; German, lod; Italian, iodio; Spanish, yodo

•NUCLEAR

(iyo-deen]

A T A

Number of isotopes (including nuclear isomers): 37

Isotope mass range: 110 -> 140

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin I

Nuclear magnetic Uses moment p

l27I

126.904 473

100

5/2+

+2.81328

NMR

A table of radioactive isotopes is given in Appendix 1, on p242.

NMR [Reference: Nal (aq)]

127I 0.0934 530 5.3525 x 107 -0.789 x 10-28 20.007

Relative sensitivity ('ll = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T'1 s-1 Nuclear quadrupole moment/m2 Frequency ('H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

DATA

Ground state electron configuration: [Kr]4d105s25p5 Term symbol: 3P3/2 Electron affinity (M -> M J/kJ mol-1: 295.2 Ionization energies/kj mol-1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M+ M24 M3+ M44 M5+ M6+ M7+ M8+ M94

1008.4 -> M4 1845.9 M2+ 3200 -+ M34 (4100) M4+ (5000) ~+ M54 (7400) M64 (8700) M7+ -+ M84 (16400) -+ M9+ (19 300) -+ M104 (22 100)

•CRYSTAL

Electron binding energies/eV K

L, Ln Lm M,

Mu M,n M„, Mv

Is 2s

Main lines in atomic spectrum

(Wavelength/nm(species)) 511.929 (I) 533.822 (II) 562.569 (II)

33169 5188 4852 4557 1072 931 875 631 620

2Pl/2 2P3Z2

3s 3Pt« 3p3/2

3d3,2 3d5,2

804.374 (I)

905.833 (I) 911.391 (I)

continued in Appendix 2, p256

DA T A

Crystal structure (cell dimensions/pm), space group

orthorhombic (a = 726.47, b= 478.57, c= 979.08), Cmca X-ray diffraction: mass absorption coefficients (p/p)/cm2 g1: CuK„ 294 MoK„ 37.1 Neutron scattering length, bl 10-12 cm: 0.528 Thermal neutron capture cross-section, era/bams:6.2

•GEOLOGICAL Minerals Minerals are very rare. Iodine cycles through the environment, and rain water contains about 0.7 p.p.b. Mineral Iodargyrite Lautarite

Formula (5-AgI Ca(I03)2

Density 5.69 4.519

Hardness 1.5 3.5-4

Crystal appearance hex., res,/adam. colourless mon., col./yellow, transparent

Chief source: from brines, which may have 50

Abundances

ppm of iodide, and the Chilean nitrate deposits which contain up to 0.3% calcium iodate. Some iodine is also extracted from seaweed.

Sun (relative to H = 1

World production/tonnes y-1: 12 000 (elemental

iodine) Producing areas: Chile, Japan. Reserves/tonnes: 2.6 x 106 Specimen: available as crystals. Warning!

x

1012): n.a.

Earth’s crust/p.p.m.: 0.14 Atmosphere/p.p.m. (volume): trace Seawater/p. p.m.:

Atlantic surface: 0.0489 Atlantic deep: 0.056 Pacific surface: 0.043 Pacific deep: 0.058 Residence time/years: 300 000 Classification: scavenged as I(-1), recycled as I(V) Oxidation state: -I and V, mainly V

103

Atomic number: 77 Relative atomic mass (,2C= 12.0000): 192.217

CAS: [7439-88-5]

•CHEMICAL Description: Iridium is a hard, lustrous, silvery metal of the so-called platinum group. It is

unaffected by air, water, and acids, but dissolves in molten alkali. Iridium is used in special alloys and spark plugs. Radii/pm: Ir4+ 66; Ir3' 75; Ir2’ 89; atomic 136; covalent 126 Electronegativity: 2.20 (Pauling); 1.55 (Allred); 5.4 eV (absolute) Effective nuclear charge: 3.90 (Slater); 10.57 (Clementi); 15.33 (Froese-Fischer)

Standard reduction potentials £7V IV

III 0.926 0.223

IrO,

1.156

.3+

Ir

Iro

0.867

o_

0.86

Ir

[IrClg]2'-[IrCl6]3

Oxidation states Ir"1 Ir° Ir1 Ir”

d10 d9 d8 d7

Ir111 Irlv Irv Ir11

rare [Ir(CO)3(PPh3)]" rare [Ir4(CO)12], [Ir6(CO)16] [IrCl(CO)(PPh3)2] IrCl2

d6 d5 d4 d3

IrF3, IrCl3 etc., [lrClB]3" (aq) Ir02, IrF4, IrS2, [IrCl6]2" (aq) IrF5, [IrFrJ" IrF6

•PHYSICAL Melting point/K: 2683

mol ': 26.4 AHvJk] mol'1: 563.6

Boiling point/K: 4403

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

AfH6/kJ mol * 0 665.3

.

AfG®/kJ mol1 0 617.9

S®/J K"1 mol"1 35.48 193.578

Density/kg m 3: 22 560 [290 K]; 20 000 [liquid at m.p.[

C„/J K"1 mol"1 25.10 20.786

Young’s modulus/GPa: 528

Molar volume/cm3: 8.57

Rigidity modulus/GPa: 209

Thermal conductivity/W m"1 K"1: 147 [300 K]

Bulk modulus/GPa: 371

Coefficient of linear thermal expansion / K"1:6.4 x 10"6

Poisson's ratio/ GPa: 0.26

Electrical resistivity In m: 5.3 x 10"8 (s) Mass magnetic susceptibility/kg 1 m3: +1.67

•BIOLOGICAL

x

10"9 (s)

DATA

Biological role

Levels in humans

None.

Blood/mg

Toxicity

Bone/p.p.m.:

Toxic intake: the pure metal is clinically

inert; data on compounds is sparse. Lethal intake: LD50 (chloride, oral, mouse) = 8.12 mg kg"1

Hazards Indium chloride is moderately toxic by ingestion, but most compounds are insoluble and not absorbed by the body.

104

dm"3: n.a., but very low n.a. Liver/p.p.m.: n.a. Muscle/p.p.m.: c. 2 x 10"5 Daily dietary intake: n.a. but very low Total mass of element in average (70 kgl person:

n.a

Discovered in 1803 by S. Tennant at London, England.

Iridium

[Latin, iris = rainbow] French, iridium; German, Iridium; Italian, iridur, Spanish, iridio

•NUCLEAR

[irid-iuhm]

DATA

Number of isotopes (including nuclear isomers): 40

Isotope mass range: 170 -> 198

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin I

Nuclear magnetic Uses moment p

I91Ir

190.960584

37.3

3/2+

+0.1462

E, NMR

ls3Ir

192.962 917

62.7

3/2+

+0.1592

E, NMR

A table of radioactive isotopes is given in Appendix 1, on p242.

NMR [Never used] Relative sensitivity (‘H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T"’s"1 Nuclear quadrupole moment/m2 Frequency (‘H = 100 Flz; 2.3488T)/MHz

•ELECTRON

SHELL

mIr 2.53 X 10'5 0.023 0.539 xlO7 +0.816 xlO'28 1.718

193 Jj.

3.27 xlO'5 0.050 0.391 x 107 +0.751 xlO'28 1.871

DATA

Ground state electron configuration: [Xe]4fM5d76s2 Term symbol: 4f9C Electron affinity (M -> M')/kJ mol'1: 151 Ionization energies/kj mol ’:

1. 2. 3. 4. 5. 6. 7. 8. 9.

M M+ M2* M3+ M4v M5+ Me+ M7+ M8t

-+ -+ -> -+ -+ -> -> -+ -+

M+ M2+ M3+ M4+ M5+ M6+ M7+ M8+ M9+

880 (1680) (2600) (3800) (5500) (6900) (8500) (10 000) (11 700)

Electron binding energies /eV

Main lines in atomic spectrum

K L, Ln Lm M, M„ Mm MIV Mv

[Wavelength / nm (species) ] 203.357 (I) 208.882 (I) (AA) 209.263 (I) 215.805 (I) 254.397 (I) 263.971 (I) 322.078 (I)

Is 2s 2pI(2 2p3/2 3s 3p1/2 3p3i2 3d3/2 3d5/2

76111 13 419 12824 11215 3174 2909 2551 2116 2040

continued in Appendix 2, p256

•CRYSTAL

DATA

Crystal structure (cell dimensions/pm), space group

f.c.c. (a = 383.92), Fm3m X-ray diffraction: mass absorption coefficients (p/p)/cm2 g'1: CuKa 193 MoK„ 110 Neutron scattering length, bl 10"12 cm: 1.06 Thermal neutron capture cross-section, a,/bams: 425

• GEOLOGICAL Minerals Found as the native element. Mineral Iridium Iridosmine Osmiridium

Formula Ir (Os,hj (Ir,Os)

Density 22.4 20 20

Hardness 6-6.5 6-7 6-7

Crystal appearance cub., met. white hex., met. white /grey cub., met. white

Chief ores: osmiridium; also found with

Abundances

platinum ores

Sun (relative to H = 1 x 1012): 7.1

World production/tonnes y'1:3

Earth’s crust/p.p.m.: c.3x 10"6 Seawater/p.p.m.: n.a. but very low

Main mining areas: Canada for native element; see

also platinum.

Residence time/years: n.a.

Reserves/tonnes: n.a. Specimen: available as foil, powder, sponge or

wire. Safe.

105

Atomic number: 26 Relative atomic mass (12C = 12.0000): 55.845

CAS: [7439-89-6]

CHEMICAL Description: Iron, when absolutely pure, is lustrous, silvery and soft (workable). This is the most important of all the metals and it is used chiefly as steel in which there is carbon (up to 1.7%). Stainless steels are alloys with other metals, mainly nickel. Iron rusts in damp air and dissolves readily in dilute acids. Its uses are legion. Radii/pm: Fe32 67; Fe2* 82; atomic 124; covalent 116; van der Waals n.a. Electronegativity: 1.83 (Pauling); 1.64 (Allred); 4.06 eV (absolute) Effective nuclear charge: 3.75 (Slater); 5.43 (Clementi); 7.40 (Froese-Fischer)

Standard reduction potentials £"7V VI

III

II -0.04

Fe

acid (pH 0)

0.771

3+

[Fe(CN)6] base (pH 14)

[Fe04r

c. 0.55

3-

— Fe

0.361

o-

-[Fe(CN)6]2 c. -0.69

FeO,

-0.44

2+

-1.16

c. -0.8

HFe02“

Fe Fe Fe

Oxidation states Fe"'1 Fe"1 Fe° Fe' Fe"

d10 d9 d8 d7 d6

rare [Fe(CO)4]2“ rare [Fe2(CO)8]2" [Fe(CO)5] rare [Fe(NO)(OH2)5]2t FeO, FeS2 (= Fe'V"), Fe(OH) [Fe(OH2)6]2+(aq), FeF2, [Fe(ti-C5H5)2] etc.

•PHYSICAL

Fe"1

d5

FeIV Fev Fevl

d4 d3 d2

Fe203, Fe304, (= Fen0.Fem203), FeF3, FeCl3, Fe(OH)(0), [Fe(OH2)6]3+(aq) etc. rare, some complexes [Fe04]3_ ? [Fe04]2"

DATA

Melting point/K: 1808

AWf^/kJ mol': 14.9 AWvap/kJ mol"1: 351.0

Boiling point /K: 3023

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

A,H®/kJ mol-1 0 416.3

AfG*7kJ mol-1 0 370.7

S M3M3+ M4+ M4+ -» M57 M5+ M6+ M6+ -> M7+ M7+ M8+ M8t -> M9+ M9+ M10+

K L, Ln I+u M, Mn Mln

759.3 1561 2957 5290 7240 9600 12 100 14 575 22 678 25 290

•CRYSTAL

Is 2s 2Pl/2 2p3/2 3s 3pl/2 3pa/2

Main lines in atomic spectrum

[Wavelength/nmCspecies)] 248.327 (I) (AA) 248.814 (I) 252.285 (I) 344.061 (I) 371.994 (I) 373.713 (I) 374.556 0) 385.991 (I)

7112 844.6 719.9 706.8 91.3 52.7 52.7

DATA

Crystal structure (cell dimensions/pm), space group

a-Fe b.c.c. (a = 286.645), Im3m P-Fe not true allotrope y-Fe c.c.p. {a = 364.68), Fm3m 149

Key isotopes Nuclide

Atomic mass

“La*

137.907 105

0,09

“La

138.906347

99.91

Natural abundance (%)

Nuclear spin I

Nuclear magnetic Uses moment p

5+

+3.7139

E, NMR

7/2+

+2.783 2

E, NMR

* 138La is radioactive with a half-life of 1.0 x 10“ y and decay mode |3~ (1.04 MeV) 34%, EC (1.75 MeV) 66%; y. A table of radioactive isotopes is given in Appendix 1, on p243.

138La 0.0919 0.43 3.5295 xlO7 +0.450 x 10-28 13.193

NMR (Reference; 0.01MLaCl3] Relative sensitivity (‘H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad 'I' ‘s ' Nuclear quadrupole moment/m2 Frequency ('H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

I39La 0.0592 336 3.7787 xlO7 +0.200 xlO-28 14.126

DATA

Ground state electron configuration: [Xe]5d‘6s2 Term symbol: 2D3/2 Electron affinity (M -> M“)/kJ mol-1: c. 50 Ionization energies/kj mol-1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M+ M24 M3+ M4t M5+ M6+ M74 M84 M94

-> ~> -» > ~> -> -> -+ ->

538.1 M4 1067 M2+ 1850 M34 4819 M4+ (6400) M5+ (7600) M6+ (9600) M7+ M84 (11000) M94 (12 400) M104 (15 900)

•CRYSTAL

Electron binding energies/eV

K L, 1+t Mn

M, Mb Mm Mrv

Mv

Is 2s 2pi/z 2p3/2 3s 3pt/2 3p3/2 3d3(2 3d5/2

38 925 6266 5891 5483 1362 1209 1128 853 836

Main lines in atomic spectrum

[Wavelength / nm (species) 1 394.910 (II) 408.672 (II) 418.732 (II) 433.374 (II) 550.134 (I) (AA)

continued in Appendix 2, p256

DATA

Crystal structure (cell dimensions/pm), space group

a-La hexagonal (a = 377.0, c= 121.59), P63/mmc p-Laf.c.c. (a = 529.6), Fm3m y-La b.c.c. [a = 426), Im3m T(a -> p) = 583 K; r(p^y) = 1137K X-ray diffraction: mass absorption coefficients (p/p)/cm2 g-1: CuKa 341 MoKI; 45.8 Neutron scattering length, h/10 12 cm: 0.824 Thermal neutron capture cross-section, rja/barns: 8.98

GEOLOGICAL Minerals Mineral Allanite Bastnasite-La* Cerite Monazite-La*

Formula Density Hardness Ca(Ce,La)(Al,Fe)3(Si04)30H 4.0 5.5-6.0 (La,Ce, etc.)C03(F,OH) n.a. n.a. (Ce,La,Ca)9(Mg,Fe)Si7(0,OH,F)28 4.75 5 (La, Ce, Nd, Th, etc.)P04 5.20 5-5.5

Crystal appearance mon., sub-met. black hex. rhom., res. black mon., waxy/vit. yellow-brown

* Varieties of these minerals that are particularly rich in lanthanum. Chief ores: monazite, bastnasite World production/tonnes y-1:12 500 Main mining areas: USA, Brazil, India, Sri Lanka,

Australia. Reserves/tonnes: c. 6 x 108 Specimen: available as chips, ingots or powder.

Care!

Abundances Sun (relative to H = 1 x 1012): 13.5 Earth’s crust/p.p.m.: 32 Seawater/p.p.m.:

Atlantic surface: 1.8 x 10-6 Atlantic deep: 3.8 x 10-6 Pacific surface: 2.6 x 10-6 Pacific deep: 6.9 x 10-6 Residence time/years: 200 Classification: recycled Oxidation state: III

Atomic number: 103 Relative atomic mass (,2C = 12.0000): 262.11 (Lr-262)

•CHEMICAL

CAS: [22537-19-5]

DAT

Description: Lawrencium is a radioactive metal element which does not occur naturally, and is of research interest only. Radii/pm: Lr4* 83; Lr3* 88; Lr2* 112; atomic n.a. Electronegativity: 1.3 (Pauling) Effective nuclear charge: 1.80 (Slater); n.a. (Clementi); (n.a.) Froese-Fischer

Standard reduction potentials ZT7V III

II

o

-2.1

i Lr3+_£^Lr2+

| L

Oxidation states Lr11 Lrm

d1 [f14]

Lr2+ ? Lr3* (aq)

•PHYSICAL

DATA Affusion/kJ mol'1: n.a. Atfvap/kJ mol'1: n.a.

Melting point/K: n.a. Boiling point/K: n.a.

Thermodynamic properties (298.15 K, o.l MPa) State Solid Gas

AfH®/kJ mol'1 0 n.a.

A,G*7kJ mol'1 0 n.a.

S*7J K 1 mol1 n.a. n.a.

Density/kg m“3: n.a. Molar volume/cm3: n.a. Thermal conductivity/W m"1 K'1: 10 (est.) [300 K] Coefficient of linear thermal expansion/K'1: n.a. Electrical resistivityIn m: n.a. Mass magnetic susceptibility/kg'1 m3: n.a.

BIOLOGICAL Biological role

Levels in humans

None.

Nil

Toxicity

Daily dietary intake:

Toxic intake: n.a. Lethal intake: n.a.

Hazards Lawrencium is never encountered normally, and relatively few atoms have ever been made. It would be dangerous because of its intense radioactivity.

112

nil

Total mass of element in average (70 kg) person:

nil

Cp/I K 1 mol 1 n.a. n.a.

Discovery: see Nuclear Data section. [Named after Ernest O. Lawrence, inventor of the cyclotron!

Lawrencium

French, lawrencium; German, Lawrencium; Italian, inwrentio; Spanish, lawrencio

•NUCLEAR

(law-ren-see-uhml

DATA

Discovery: Lawrencium was prepared in 1961 by A. Ghiorso, T. Sikkeland, A.E. Larsh and R.M.

Latimer at Berkeley, California, USA. Number of isotopes (including nuclear isomers): 10

Isotope mass range: 253 -> 262

Key isotopes Nuclide

Atomic mass Half life (T1/2) Decay mode and energy (MeV)

K3Lr

253.095 190

1.3 s

^Lr

254.096320

13 s

a a

^Lr

255.096670

22 s

a (8.80); EC

256Lr

256.098490

26 s

a (8.554) 99.7%; SF 0.3%

^Lr

257.099480

0.65 s

a (9.30)

^Lr

258.101 710

3.9 s

a (9.00)

®Lr

259.102900

6.1s

a (8.70); SF

mu

260.105320

3m

a (8.30); EC

M1Lr 2®Lr

39 m

SF

261m

EC

Nuclear Nucl. mag. Uses spin I moment fi

NMR [Not recorded]

• ELECTRON

SHELL

DATA

Ground state electron configuration: [Rn]5f146d‘7s2 Term symbol: 2D5/2 Electron affinity (M -» M )/kJ mol"1: n.a. Ionization energies/kj mol"1:

1. M

-4

M+

n.a.

Electron binding energies/eV

Main lines in atomic spectrum

n.a.

[Wavelength/nm(species)] n.a.

•CRYSTAL Crystal structure (cell dimensions/pm), space group

X-ray diffraction: mass absorption coefficients (p/p)/cm2 g"1: CuKa n.a. MoKB n.a. Neutron scattering length, bl 10"lz cm: n.a. Thermal neutron capture cross-section, M4+ 6640 5. M4’ -4 M5* (8100) 6. M5+ -4 M6+ (9900) 7. M6+ -4 M7* (11800) 8. M7+ -4 9. M8+ -4 M9+ (13 700) 10. M9+ -4 M10+ (16 700)

•CRYSTAL

Main lines in atomic spectrum [Wavelength/nm(species)] 217.000 (I) (AA) 261.418 (I) 283.305 (I) 357.273 (D 363.957 (I) 368.346 (I)

Electron binding energies / eV Is 88 005 K 2s 15 861 L, 15 200 2Pl/2 Ln 13 055 2p3/2 I+n 3s 3851 M, 3554 3p,/2 Mb 3066 Mm 3P3/2 2586 3d3/2 2484 3d5/2 Mv

405.781 (I)

continued in Appendix 2, p256

DATA

Crystal structure (cell dimensions/pm), space group f.c.c. (a = 495.00), Fm3m X-ray diffraction: mass absorption coefficients fu/p)/cm2 g"1: CuK„ 232 MoKr> 120 Neutron scattering length, bl 10“12 cm: 0.9405 Thermal neutron capture cross-section, cr ,,/barns: 0.171

•GEOLOGICAL Minerals Mineral Anglesite Boulangerite Bournonite Cerussite Galena Minium Pyromorphite

Formula PbS04 Pb5Sb4Su PbCuSbS3 PbC03 PbS Pb304 Pb5(P04)3Cl

Density 6.38 6.23 5.8 6.55 7.58 9.05 7.04

Hardness 2.5-3 2.5-3 2.5-3 3-3.5 2.6 2.5 3.5-4

Chief ores: galena is the main ore (with silver as a by-product), pyromorphite, boulangerite and cerussite are minor ores. World production /tonnes y"1:2.8 x 106 Main mining areas: galena in USA, Australia, Mexico, West Germany; boulangerite in France. Reserves/tonnes: 85 x 106 Specimen: available as foil, granules, ingots, powder, rod, shot and wire. Care!

Crystal appearance orth, adam./greasy white orth., met. bluish-grey orth., met. steel-grey orth., adam./vit. col. cub., met. grey tet., greasy red/brown hex., barrel-shaped crystals, often hollow

Abundances Sun (relative to H = 1 x 10'2): 85.1 Earth’s crust/p.p.m.: 14 Atmosphere/p.p.m. (volume): trace Seawater/p.p.m.: Atlantic surface: 30 x 10-6 Atlantic deep: 4.0 x 10 6 Pacific surface: 10 x 10"* Pacific deep: 1 x 10"6 Residence time/years: 50 Classification: scavenged Oxidation state: II

115

Li

Atomic number: 3

CAS:

Relative atomic mass (l2C = 12.0000): 6.941

[7439-93-2]

•CHEMICAL Discovery: Lithium was discovered in 1817 by J.A. Arfvedson at Stockholm, Sweden.

Isolated in 1821 by W.T. Brande. Description: Lithium is a soft, silvery-white, metal that reacts slowly with oxygen and water. It is used in light-weight alloys, especially with aluminium and magnesium, and in greases, batteries, glass, medicine and nuclear bombs. Radii/pm: Li* 78; atomic 152; covalent 123 Electronegativity: 0.98 (Pauling); 0.97 (Allred); 3.01 eV (absolute) Effective nuclear charge: 1.30 (Slater); 1.28 (Clementi); 1.55 (Froese-Fischer)

Standard reduction potentials F7V I

0

Li+ —=3t)4Q

y

Oxidation states LL1 Li1

s2 [He]

Li solutions in liquid ammonia Li20, LiOH, LiH, LiAlH4, LiF, LiCl etc., [Li(OH2)4]+ (aq), Li2C03, salts of Li\ some complexes, [Li(CH3)]4, [Li(12-crown-4)]+

• PHYSICAL

DATA

Melting point/K: 453.69

AW tusk*./kj mol'1: 4.60 AW.up/kJ mol-1: 134.7

Boiling point /K: 1620

Thermodynamic properties (298.15 K, o.l MPa) State Solid Gas

AfjF/*7kJ mol"1 0 159.37

AfG*/kJ mol'1 0 126.66

SVJ K1 mol"'

29.12 138.77

Cp/J K 1 mol"1 24.77 20.786

Density/kg m"3: 534 [293 K]; 515 [liquid m.p.]

Young’s modulus/GPa: 4.91

Molar volume/cm3: 13.00

Rigidity modulus/GPa: 4.24

Thermal conductivity/W m"1 K'1: 84.7 [300 K]

Bulk modulus/GPa: n.a.

Coefficient of linear thermal expansion/K'1:56 x 10"6

Poisson’s ratio/GPa: 0.36

Electrical resistivity IQ m: 8.55 x 10"8 [273 K] Mass magnetic susceptibility/kg"1 m3: +2.56x 10“ (s)

•BIOLOGICAL Biological role

Levels in humans

None; but lithium acts to stimulate metabolism and can control manic-depressive disorders.

Blood/mg dm"3:0.004

Toxicity

Bone/p. p.m.: 1.3 Liver/p.p.m.: 0.025 Muscle/p.p.m.: 0.023 Daily dietary intake: 0.1- 2mg

Toxic intake: 20 - 200 g (see under hazards)

Total mass of element

Lethal intake: LD50 (carbonate, oral, rat) =

in average (70 kg) person: 7 mg

525 mg kg"1

Hazards Lithium is moderately toxic by ingestion but there are wide variations of tolerance. Even lithium carbonate, which is used in psychiatry, is prescribed at doses near to the toxic level. Some lithium compounds are carcinogenic and teratogenic.

116

Discovery: see Chemical Data section.

Lithium

(Greek, lithos = stone) French, lithium; German, Lithium; Italian, litio; Spanish, litio

(lith-iuhm)

• NUCLEAR Number of isotopes (including nuclear isomers): 5

Isotope mass range: 5 -> 9

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

r>Li

6.015121

7.5

;Li

7.016003

92.5

Nuclear spin I

Nuclear magnetic Uses moment u

1+

+0.8220467

E, NMR

3/2-

+3.256424

E, NMR

A table of radioactive isotopes is given in Appendix 1, on p243.

6Li 8.50 x 10'3 3.58 3.9366 xlO7 -0.00082 x 10'28 14.716

NMR [Reference: LiCl (aq)] Relative sensitivity (’H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T1 s"1 Nuclear quadrupole moment/m2 Frequency (‘H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

7Li 0.29 1540 10.3964 xlO7 -0.041 x 10'28 38.863

DATA

Ground state electron configuration: [He]2s‘ Term symbol: 2S1/2 Electron affinity (M -> M')/kJ mol'1: 59.6 Ionization energies/kj mol 1:

1. M -+ M* 2. M* -* M2t 3. M2+ -4 M3t

513.3 7298.0 11814.8

Electron binding energies / eV

Main lines in atomic spectrum

K

[Wavelength/nm(species)] 323.266 (I) 548.355 (II) 548.565 (II) 610.362 (I)

Is

54.7

670.776 (I) 670.791 (I) (AA)

•CRYSTAL Crystal structure (cell dimensions/pm), space group

a-Li b.c.c. (a = 351.00), Im3m )3-Li f.c.c. (a = 437.9), Fm3m a form stable at room temperature; converts to p form at low temperatures X-ray diffraction: mass absorption coefficients (p/p)lcm2 g ': CuKa 0.716 MoK„ 0.217 Neutron scattering length, bl 1012 cm: -0.190 Thermal neutron capture cross-section, 1 x 1024

in the sea Specimen: available as chips, granules, powder, ribbon, rod or turnings. Safe.

Residence time/years: 1 x 107 Classification: accumulating Oxidation state: II

121

Mn

Atomic number: 25

CAS:

Relative atomic mass (12C = 12.0000): 54.93805

[7439-96-5]



• CHEMICAL

DATA

Description: Manganese is a hard, brittle, silvery metal. It is reactive when pure, burns in

oxygen, reacts with water and dissolves in dilute acids. It is used in steel production and to make ceramics. Its compounds are used as feed supplements and fertilizer additives. Radii/pm: Mn4+ 52; Mn3* 70; Mn2* 91; atomic 124; covalent 117 Electronegativity: 1.55 (Pauling); 1.60 (Allred); 3.72 eV (absolute) Effective nuclear charge: 3.60 (Slater); 5.23 (Clementi); 7.17 (Froese-Fischer)

Standard reduction potentials ElV VII

vi

v

in

IV

ii

1.51 1.70 0.56 0.27 , 4.27 1 0.95 •>. 1.50 •>. -1.18 [MnO„r — [Mn04r — [Mn04]J — Mn02-Mni+-Mn2+-Mn

acid

2.27

1.23 0.34

0.60 0.56 , 0.27 O 0.96 [Mn04]" — [Mn04]2 — [Mn04[3 — MnO 2

base

0.15

0.62

-0.25

-1.56

Mn203 — Mn(OH)2-0.05

Oxidation states Mn'm Mn'" Mn'1 Mn° Mn1 Mn"

d10 d9 d8 d7 d6 d5

[MnCO(NO)3], [Mn(CO)4]3“ some complexes known [Mn(CO)5]' [Mn2(CO)10] [Mn(CN)6]', [MnH(CO)5] MnO, Mn304 (=MnllMn,,1204). [Mn(OH2)6]2* (aq); MnF2, MnCl2 etc., salts, complexes

•PHYSICAL

Mn111 d4 Mn'v Mnv Mn71 Mn™

d3 d2 d1 d°

Mn203, [Mn(OH2)6]3* (aq) unstable; MnF3, [MnCls]2' MnO,, MnF4, [MnFB]2' [MnO,]3[Mn04]2' [Ar] Mn207, [Mn04]"

DATA

Melting point/K: 1517

AWf^/kJ mol': 14.4

Boiling point/K: 2235

Af/,ap/kJ moP1: 219.7

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

Ar//°/kI mol“* 0 280.7

A,G*7kJ mol'1 0 238.5

S°lJ K 1 mol'1 32.01 173.70

C„/J K'1 mol'1 26.32 20.79

Density/kg m~3: 7440 (a) [293 K]; 6430 [liquid at m.p.]

Young’s modulus/GPa: 191

Molar volume/cm3: 7.38

Rigidity modulus/GPa: 79.5

Thermal conductivity/W m 1 K"1: 7.82 [300 K]

Bulk modulus/GPa: n.a.

Coefficient of linear thermal expansion/K ‘: 22 x 10

Poisson's ratio/GPa: 0.24

Electrical resistivity/Q m: 185.0

x

10 8 [298 K]

Mass magnetic susceptibility/kg“'m3: +1.21 x 10"7 (s)

BIOLOGICAL Biological role

Levels in humans

Essential to all species.

Blood/mg dm'3:0.0016-0.075

Toxicity

Bone/p.p.m.:

Lethal intake: LD50 (chloride, oral, mouse) =

0.2 - 100 3.6 - 9.6 Muscle/p.p.m.: 0.2 - 2.3 Daily dietary intake: 0.4 - 10

1715 mg kg'1

Total mass of element

Hazards

in average (70 kg) person:

Toxic intake: slightly toxic by ingestion

Few poisonings have been caused by ingesting manganese compounds, but exposure to dust or fumes is a health hazard and working conditions should not exceed 5 mg m'3 even for short periods. Its compounds are experimental carcinogens and teratogens.

122

Liver/p.p.m.:

mg

12 mg

Isolated in 1774 by J. G. Gahn at Stockholm, Sweden.

Manganese

[Latin, magties = magnet, or magnesia nigri = black magnesia (Mn02)] French, manganese-, German, Mangan; Italian, manganese-, Spanish, manganeso

[tnan-gan-eezl

•NUCLEAR Number of isotopes (including nuclear isomers): 15

Isotope mass range: 49 -> 62

Key isotopes Nuclide

Atomic mass

Natural abundance (%}

Nuclear spin I

Nuclear magnetic Uses moment p

55Mn

54.938047

100

5/2-

+3.4532

NMR

A table of radioactive isotopes is given in Appendix 1, on p244.

NMR [Reference: KMn04 (aq)]

55Mn 0.18 994 6.6195 x 107 +0.330 x 10 28 24.664

Relative sensitivity ('H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T 's' Nuclear quadrupole moment/m2 Frequency (4H = 100 Hz; 2.3488T) /MHz

•ELECTRON

SHELL

Ground state electron configuration: [Ar]3d54s2 Term symbol: 6S5/2 Electron affinity (M

> M )/kJ mol"1: < 0

Ionization energies/kj mol 1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M4 M2+ M34 M4+ M54 M64 M74 M84 M94

-> -+ -+ -> -+ -+ -> -+ -> -+

M4 M24 M3+ M44 M54 M64 M74 M84 M94 M104

•CRYSTAL

717.4 1509.0 3248.4 4940 6990 9200 11508 18 956 21 400 23 960

Electron binding energies/eV

Main lines in atomic spectrum

K L, Lh

[Wavelength/nm(species)[ 257.610 (I) 279.482 (I) (AA) 279.827 (I)

Liii

M, Mn Mm

Is 2s 2pi« 2p.1/2 3s 3Pl/2

3p3/2

6539 769.1 649.9 638.7 82.3 47.2 47.2

403.076 (I)

403.307 (I) 403.449 (I)

DATA

Crystal structure (cell dimensions/pm), space group

o-Mnb.c.c. (a= 891.39), I43m /?-Mn b.c.c. (a= 631.45), P4J32 y-Mn f.c.c. (a = 386.3), Fm3m 5-Mn b.c.c. (a = 308.1), Im3m r(a-+j3) = 973 K; T(^+y) = 1352 K; T(y^S) = 1413 K X-ray diffraction: mass absorption coefficients (p/p)/cm2 g"1: CuK0 285 MoKa 34.7 Neutron scattering length, bl 10"12 cm: -0.373 Thermal neutron capture cross-section, o-a/barns: 13.3

•GEOLOGICAL Minerals Many manganese minerals are known. Mineral Bixbyite Manganite Pyrolusite Rhodochrosite Rhodonite* Romanechite

Formula (Mn,Fe)203 y-MnO(OH) ;3-Mn02 MnCQ3 (Mn,Fe,Mg)S103 BaMn9016 (OH)4

Density Hardness 4.975 6-6.5 4.33 4 2-6 5.06 3.4-3.6 3.5-4 5.5-6.5 3.6 3.7-4.7 5-6

Crystal appearance cub. met. black mon., met. grey-black tet., met. grey-black rhom., vit. pink trie., vit. rose-pink mon., met. black, fern-like

* used in jewelry Chief ores: pyrolusite, romanechite (also known

Abundances

as psilomelane), manganite (useful but rare)

Sun (relative to H = 1 x 1012): 2.63 x 105

World production /tonnes y"1:6.22 x 106

Earth’s crust/p.p.m.: 950 Seawater/p.p.m.:

Main mining areas: South Africa, Russia, Gabon,

Australia, Brazil Reserves/tonnes: 3.6 x 109 (plus ocean floor

nodules which are 24% Mn) Specimen: available as chips, flake or powder.

Safe.

Atlantic surface: 1.0 x 10 4 Atlantic deep: 0.96 x 104 Pacific surface: 1.0 x 104 Pacific deep: 0.4 x 10"* Residence time/years: 50 Classification: scavenged Oxidation state: II

123

Atomic number:

109

CAS:

Relative atomic mass (12C = 12.0000): (266)

•CHEMICAL

[54038-01-6]

DATA

Description: Meitnerium is a radioactive metal, of which only a few atoms have ever been

made. Radii /pm: Mt3+ 83 (est.) Electronegativity: n.a. Effective nuclear charge: n.a.

Standard reduction potentials £"7V III

0 o.

+0.8 (est.)

Mt3-

Mt

Oxidation states Mt1 Mt" Mt"1 MtIV

d7 d6 d5 d4

predicted predicted, most stable? predicted predicted

• PHYSICAL Melting point/K: n.a.

AW^/kJ mol"1: n.a. A//vap/kJ mol"1: n.a. Atf^/kJ mol"1: 594 (est.)

Boiling point/K: n.a.

Thermodynamic properties (298.15 K, o.l MPa) State Solid Gas

Af//e/kJ mol"1 0 n.a.

AfGe/kJ mol"1 0 n.a.

SV] K" mol"1 n.a. n.a.

Density/kg m"3: n.a. Molar volume/cm3: n.a. Thermal conductivity/W m"1 K"1: n.a. Coefficient of linear thermal expansion/K"1: n.a. Electrical resistivity In m: n.a. Mass magnetic susceptibility/kg"1 m3: n.a.

•BIOLOGICAL Biological role

Levels in humans

None.

nil

Toxicity Toxic intake: n.a. Lethal intake: n.a.

Hazards Meitnerium is never encountered normally, and only a few atoms have ever been made. It would be dangerous because of its intense radioactivity.

124

Daily dietary intake:

nil

Total mass of element in average (70 kg) person:

nil

C„/J K"1 mol1 n.a. n.a.

Discovery: see Nuclear Data section. INamed after Lise Meitner, Austrian physicist who first suggested spontaneous nuclear fission]

Meitnerium

French, meitnerium; German, Meitnerium; Italian, meitnerio; Spanish, meitnerio

•NUCLEAR

[miyt-neer-iuhm]

DATA

Discovery: Meitnerium was first made in 1982 by Peter Armbruster, Gottfried Miinzenberg

and their co-workers at Gesellschaft fur Schwerionenforschung in Darmstadt, Germany. Number of isotopes (including nuclear isomers): 1

Isotope mass range: 266

Key isotopes Nuclide

266Mt

Atomic mass

266.1378

Half life (T„2) Decay mode and energy (MeV)

c. 3.4 x 10 3 s

a

Nuclear Nucl. mag. Uses spin I moment p n.a.

n.a.

NMR [Not recorded]

•ELECTRON

SHELL

DATA

Ground state electron configuration: [Rn]5f146d77s2 Term symbol: %2 Electron affinity (M -> M")/kJ mol1: n.a. Ionization energies/kj mol1:

1. M

-4

M*

840 (est.)

Electron binding energies/eV

Main lines in atomic spectrum

n.a.

[Wavelength /nm(species)] n.a.

CRYSTAL Crystal structure (cell dimensions/pm), space group

X-ray diffraction: mass absorption coefficients (p/p)/cm2 g'1: CuKa n.a. MoKa n.a. Neutron scattering length, b/10"12 cm: n.a. Thermal neutron capture cross-section, 20%

250Md

250.084340

50 s

EC (4.54) 94%; o (8.25) 6%

='Md

251.084830

4m

EC (3.702) > 94%; a (8.05) < 6%

2HMd

252.086470

2s

EC (3.73) > 50%; a (7.856) < 50%

c. 6 m

2J7Md

^Md

Nuclear Nucl. mag. Uses spin I moment fj

254Md

254.089 630

30 m

a EC (2.600)

10m

EC

255Md

255.091081

27 s

EC (1.055) 92%; a (7.911) 8%

^Md

256.093960

1.3 h

EC (2.041) 90%; a (7.483) 10%

25,Md

257.095580

5.5 h

258.098570

57 m

EC (0.450) 90%; a (7.60) 10% EC

7/2-?

258Md

8-?

52 d 259Md

1.6 h

a (7.40) SF

28”Md

27.8 d

SF

7/2-?

NMR (Not recorded]

•ELECTRON

SHELL

DATA

Ground state electron configuration: [Rn]5f137s2 Term symbol: %,2 Electron affinity (M -> M )/kJ mol1: n.a. Ionization energies/kj mol1:

1. M

-> M*

•CRYSTAL

635

Electron binding energies/eV

Main lines in atomic spectrum

n.a.

(Wavelength/nm(species)] n.a.

DATA

Crystal structure (cell dimensions/pm), space group

X-ray diffraction: mass absorption coefficients (p/p)/cm2 g': CuKa n.a. MoKa n.a. Neutron scattering length, £>/10'12 cm: n.a. Thermal neutron capture cross-section, 206

Key isotopes Nuclide

Atomic mass

196Hg .98Hg

195.965807

0.14

0+

E

197.966743

10.02

0+

E

Natural abundance (%)

Nuclear spin I

Nuclear magnetic Uses moment p

“Hg

198.968254

16.84

1/2-

200Hg

199.968300

23.13

0+

201 Hg

200.970277

13.22

3/2-

202Hg 204Hg

201.970617

29.80

0+

E

203.973467

6.85

0+

E

+0.505 8852

E, NMR E

-0.560225

E, NMR

A table of radioactive isotopes is given in Appendix 1, on p244.

NMR [Reference; Hg(CH3)2J

199Hg

Relative sensitivity ('H = 1.00)

5.67 xlO'3 5.42 4.7912 xlO7 17.827

Receptivity (13C = 1.00) Magnetogyric ratio/rad T~1 s'1 Nuclear quadrupole moment/m2 Frequency fH = 100 Hz; 2.3488T)/MHz

201Hg 1.44 xlO'3 1.08 -1.7686 xlO7 +0.386x1 O'28 6.599

SHELL

• E L E C T R

Ground state electron configuration: [Xe]4f1‘15d106s2 Term symbol: 'So Electron affinity (M -> M')/kJ mol'1: -18 Ionization energies/kj mol1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

1007.0 M M* 1809.7 M+ —> M2+ 3300 M2* -> M3* (4400) M3< -> M4+ (5900) M5+ M4+ (7400) M5+ M6t (9100) M6* -4 M7+ M7+ —> M8* (11600) M8t -4 M9+ (13 400) M9* M10* (15300)

•CRYSTAL

Electron binding energies /eV

K L, La Lm M, M„ Mm M„ Mv

Is 2s 2Pl/2 2p3/2 3s 3Pl/2 3P3/2 3d3/2 3d5,2

Main lines in atomic spectrum

[Wavelength/nm(species)l 253.652 (I) (AA) 365.015 (I) 404.656 (I) 435.833 (I) 1013.975 (I)

83102 14839 14 209 12284 3562 3279 2847 2385 2295

continued in Appendix 2. p256

DATA

Crystal structure (cell dimensions/pm), space group

a-Hg rhombohedral (a = 299.25, a = 70° 44.6'), R3m /3-Hg tetragonal (a = 399.5, c = 282.5), I4/mmm a -> p high pressure X-ray diffraction: mass absorption coefficients (p/p)/cm2 g ': CuKa 216 MoKa 117 Neutron scattering length, h/10"12 cm: 1.266 Thermal neutron capture cross-section, a,/barns: 374

•GEOLOGICAL Minerals Native mercury’ occurs naturally as tiny drops of the liquid metal usually associated with cinnabar deposits but also found in some volcanic rocks. Mineral Cinnabar

Formula HgS

Density 8.09

Chief ore: cinnabar World production /tonnes y'1:8400 Main mining areas: Spain, Italy, Yugoslavia. Reserves/tonnes: 590 000 Specimen: available as liquid of varying gr

purity of up to 99.9999%. Warning!

Hardness 2-2.5

Crystal appearance rhom. microcrystalline, scarlet mass

Abundances Sun (relative to H = 1

x

1012): < 125

Earth’s crust/p.p.m.: 0.05 Seawater/p. p.m.:

Atlantic surface: 4.9 x 10 7 Atlantic deep: 4.9 x 10"7 Pacific surface: 3.3 x 10"7 Pacific deep: 3.3 x 10"7 Residence time/years: n.a. Classification: scavenged Oxidation state: II

129

Mo

Atomic number: 42

CAS:

Relative atomic mass (12C= 12.0000): 95.94

[7439-98-7]

•CHEMICAL Description: Molybdenum is a lustrous, silvery metal which is fairly soft when pure. It is

usually obtained as a grey powder. It is attacked slowly by acids. It is used in alloys, electrodes and catalysts. Radii/pm: Mo6* 62; Mo2* 92; atomic 136; covalent 129 Electronegativity: 2.16 (Pauling); 1.30 (Allred); 3.9 eV (absolute) Effective nuclear charge: 3.45 (Slater); 6.98 (dementi); 9.95 (Froese-Fischer)

Standard reduction potentials E /V VI

V

IV

III

0.114 0.085 0.50

acid

0.17

H2Mo04— Mo2042+— Mo2024+

Mo2(OH)

4+

Mo

-0.152 0.646

-MoO?

-0.008

-Mo'3+_

-0.2

0.428

base

Mo042—

-0.780

-0.980

-Mo02-

-Mo

-0.913

Oxidation states Mo’11 d8 Mo° d6 Mo1 d5 Mo11

d4

rare [Mo(CO)5]2" rare [Mo(CO)6] rare [Mo(ti-C6H6)2]\ [Mo(CO)3bi-C5H5)]2 Mo6C112, [Mo2C18]\ MO;'* (aq)

Mom d3

MoF3, MoC13 etc., [Mo(OH2)6]3* (aq) Mo02, MoS2, MoF4, MoC14 etc. Mo™ d2 Mov d1 Mo205, MoF5, MoC15 Movl d° [Kr] Mo03, [Mo04]2" (aq), MoF6, [MoF8]2", MoF40

•PHYSICAL AHw/kj mol': 27.6

Melting point/K: 2890 Boiling point / K: 4885

Thermodynamic properties (298. State Solid Gas

Af/I®/kJ mol"1 0 658.1

K, 0.1 MPa) ArG®/kI mol"1 0 612.5

Se/J K 1 mol"1 28.66 181.950

Cp/J K“l mol1 24.06 20.786

Density/kg m"3: 10 220 [293 K]; 9330 [liquid at m.p.]

Young’s modulus/GPa: 324.8

Molar volume/cm3: 9.39

Rigidity modulus/GPa: 125.6 Bulk modulus /GPa: 261.2

Thermal conductivity/W m"1 K'1: 138 [300 K] Coefficient of linear thermal expansion/K"1:5.43 Electrical resistivity In m: 5.2

x

10"6

Poisson’s ratio/GPa: 0.293

10"8 [273 K] Mass magnetic susceptibility/kg"1 m3: +1.2 x 10"8 (s) x

•BIOLOGICAL

DATA

Biological role

Levels in humans

Essential to all species.

Blood/mg dm"3:

Toxicity

Bone/p.p.m.: < 0.7

Toxic intake: n.a.

Muscle/p.p.m.: 0.018

c.

0.001

Liver/p.p.m.: 1.3-5.8

Lethal intake: LD50 (Mo02, subcutaneous,

Daily dietary intake: 0.05 - 0.35 mg

mouse) =318 mg kg"1

Total mass of element

Hazards

in average (70 kg) person: 5 mg

Animal experiments show molybdenum compounds to be highly toxic and teratogenic, but there is little human data.

130

Isolated in 1781 by P.J. Hjelm at Uppsala, Sweden.

Molybdenum

(Greek, molybdos= lead| French, molybdene-, German, Molybddn; Italian, molibdeiw, Spanish, molibdeno

1 • N 11 C L E A R

(mol-ib-den-uhm)

DATA

1

Number of isotopes (including nuclear isomers): 23

Isotope mass range: 88 -»106

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin I

92Mo

91.906809

14.84

Or

E

94Mo

93.905 085

9.25

Or

E

Nuclear magnetic Uses moment /j

95Mo

94.905841

15.92

5/2+

96Mo

95.904 678

16.68

Or

97Mo

96.906 020

9.55

9sMo

97.905407

24.13

Or

E

""Mo

99.907477

9.63

Or

E

-0.9142

E, NMR

-0.9335

E, NMR

E

5/2+

A table of radioactive isotopes is given in Appendix 1, on p244.

NMR

[Reference: [Mo04]2’

(aq)]

95Mo

Relative sensitivity ('H = 1.00)

3.23 x 10'3 2.88 1.7433 xlO7 -0.022 x 10'28 6.514

Receptivity (13C= 1.00) Magnetogyric ratio/rad

T‘ls"1

Nuclear quadrupole moment/m2 Frequency ('H = 100 Hz; 2.3488T)/MHz

| • E L E C T R 0 N

SHELL

97Mo 3.43 xlO'3 1.84 -1.7799 xlO7 +0.255 x 1 O'28 6.652

D A T A

.

Ground state electron configuration: [Kr]4d55s’ Term symbol: 7S3 Electron affinity (M -> M~)/kJ mol'1: 72.0 Ionization energies/kj mol

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M* M2t M3+ M4t M5+ M6"

685.0 1558 2621 M3" 4480 5900 M57 6560 M6+ 12 230 M7" 14 800 M8+ M9* (16 800) M10" (19 700)

—> M* —> M2+

-> —> —» —> M7t —» M8’ —> M9+ ->

Electron binding energies/eV

Main lines in atomic spectrum

Is 20 000 2s 2866 L, 2625 2pv2 Lu 2520 2p3/2 I+ii 506.3 3s M, 411.6 Mu 3pi/2 394.0 Mnl 3p3/2 3d3,2 231.1 Mp/ 227.9 3d5/2 Mv continued in Appendix 2, p256

[Wavelength/nm (species)] 201.511 (H) 202.030 (II) 203.844 (11) 313.259 (I) (AA) 379.825 (I) 386.411 (1) 390.296 (I)

K

•CRYSTAL Crystal structure (cell dimensions/pm), space group

b.c.c. (a = 314.700), Im3m X-ray diffraction: mass absorption coefficients (/i/p)/cm2 g"1: CuKa 162 MoK0 18.4 Neutron scattering length, b/10~12 cm: 0.6715 Thermal neutron capture cross-section, a,/barns:2.60

•GEOLOGICAL

DATA

Minerals Mineral Molybdenite Wulfenite

Formula MoS, PbMoO,

Density 4.7 6.78

Hardness 1-1.5 2.7-3

Crystal appearance hex. met. grey tet., res. adam. orange

Chief ores: molybdenite; wulfenite to lesser

Abundances

extent; also obtained as a by-product of copper production.

Sun (relative to H = 1 x 1012): 145

World production /tonnes y'1: 80 000 Main mining areas: USA, Australia, Italy, Norway,

Bolivia

Earth’s crust/p.p.m.: 1.5 Seawater/p.p.m.: 0.0100 Residence time /years: 600 000 Classification: accumulating Oxidation state: VI

Reserves/tonnes: 5x 106 Specimen: available as foil, powder, rod or wire.

Safe.

131

Description: Neodymium is a silvery-white metal of the so-called rare earth group (more

correctly termed the lanthanides). It tarnishes in air, reacts slowly with cold water, rapidly with hot. Neodymium is used in alloys for permanent magnets, lasers, flints, glazes and glass. Radii/pm: Nd3+ 104; atomic 182; covalent 164 Electronegativity: 1.14 (Pauling); 1.07 (Allred); 154

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin I

,4zNd

141.907 719

27.13

0+-

143Nd

142.909 810

12.18

7/2-

144Nd*

143.910 083

23.80

Of

l45Nd

144.912570

8.30

146Nd

145.913 113

17.19

Of

E

l48Nd

147.916889

5.76

Of

E

,50Nd

149.920887

5.64

Of

E

Nuclear magnetic Uses moment g E -1.065

E, NMR E

7/2-

-0.656

E, NMR

l44Nd is radioactive with a half-life of 2.1 x 10l5y and decay mode a (1.83 MeV). A table of radioactive isotopes is given in Appendix 1, on p244.

NMR [Reference: not recorded] Relative sensitivity (‘H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad 'T's-1 Nuclear quadrupole moment/nr Frequency (‘H = 100 Hz; 2.3488T)/MHz

• ELECTRON

SHELL

143Nd

145Nd

3.38 x 10"3 2.43 -1.474 xlO7 -0.630 xlO'28 5.437

7.86x10^* 0.393 -0.913 xlO7 -0.330 xlO"28 3.346

DATA

Ground state electron configuration: [Xe]4f46s2 Term symbol: % Electron affinity (M --> M")/kJ mol-1: < 50 Electron binding energies / eV

Ionization energies/kj mol *:

1. 2. 3. 4. 5.

M M+ M2+ M3‘ M4+

—> M+ -> M2‘ M3+ -» M4t -4 M5+

K L, U Lm M, M„ Mm

529. 1035 2130 3899 5790

Mb

Mv

Is 2s 2Pl/2 2P3/2 3s 3Pl/2 3P3/2 3d3,2 3Ps«

43 569 7126 6722 6208 1575 1403 1297 1003.3 980.4

Main lines in atomic spectrum

[Wavelength/nm(species)l 386.333 (II) 395.116 (II) 401.225 (ID 406.109 (U) 430.358 (II) 495.453 (I) (AA)

continued in Appendix 2, p256

•CRYSTAL Crystal structure (cell dimensions/pm), space group

a-Nd hexagonal (a = 365.79, c= 1179.92), P63/mmc [3-Ndb.c.c. (« = 413),Im3m T[a -> p) = 1135 K high pressure form: f.c.c. (a = 480), Fm3m X-ray diffraction: mass absorption coefficients (p/p)/cm2 g ‘: CuK0 374 MoK„ 53.2 Neutron scattering length, h/10"12 cm: 0.769 Thermal neutron capture cross-section, M4+ M44 —> M5t M54 —> M6+ M64 —> M7+ M74 —> M8+ M84 —> M9+ M94 —> M'°4

2080.6 3952.2 6122 9370 12177 15 238 19 998 23 069 115 377 131 429

•CRYSTAL

Electron binding energies/eV

K L, I+i L«i

870.2 48.5 21.7 21.6

Is 2s 2p,/2 2p3/2

Main lines in atomic spectrum

[Wavelength / nm (species) ] 837.761 (I) 865.438 (1)

878.062 (I) 878.375 d) 885.387 (I)

DATA

Crystal structure (cell dimensions/pm), space group

f.c.c (a - 445.462), Fm3m h.c.p. (a = 314.5, c = 514), P63/mmc [3 K] X-ray diffraction: mass absorption coefficients (/i/p)/cm! g"1: CuK0 22.9 MoK(i 2.47 Neutron scattering length, b/10 12 cm: 0.455 Thermal neutron capture cross-section, a ,,/barns: 0.040

• GEOLOGICAL

DATA

Minerals None.

Chief source: liquid air World production/tonnes y"1: c. 1 Reserves/tonnes: 6.5x10'° (atmosphere) Specimen: available in small pressurized

canisters. Safe.

Abundances Sun (relative to H = 1 x 1012): 3.72 x 10 Earth's crust/p.p.m.: 7 x 10"5 Atmosphere/p.p.m. (volume): 18 Seawater/p.p.m.: 2 x 10"4 Residence time/years: n.a. Oxidation state: 0

135

Atomic number: 93

CAS:

Relative atomic mass (I2C = 12.0000): 237.0482

•CHEMICAL

17439-99-8]

DATA

Description: Neptunium is a silvery, radioactive metal which occurs naturally in minute

amounts in uranium ores. It is attacked by oxygen, steam and acids, but not alkalis. The metal is produced by reacting NpF3 with either lithium or barium at 1200 °C. Neptunium has been used in neutron detectors. Radii/pm: Np6t 82; Np5+ 88; Np4+ 95; Np3+ 110; atomic 150 Electronegativity: 1.36 (Pauling); 1.22 (Allred); n.a. (absolute) Effective nuclear charge: 1.80 (Slater)

Standard reduction potentials ElV VII

v

VI

IV

III

0.95

acid

base

Np M*

597

•CRYSTAL

Electron binding energies/eV

Main lines in atomic spectrum

n.a.

[Wavelength/nm(species)] 901.618 (I) 1009.199(1) 1081.745 (I) 1169.515(1) 1177.664 (I) 1214.818 (I) 1237.742 (I) 1240.799 (I) 1383.433 0

DATA

Crystal structure (cell dimensions/pm), space group

a-Np orthorhombic (a = 472.3, fa = 488.7, c = 666.3), Pmcn /J-Np tetragonal (a = 489.7, b = 338.8), P42j2 y-Np cubic (a = 352.4), Im3m T(a -»/)) = 551 K; r(/J^tf = 850K X-ray diffraction: mass absorption coefficients (p/p)/cm2 g ‘: CuKa n.a. MoKa n.a. Neutron scattering length, fa/10 12 cm: 1.055 Thermal neutron capture cross-section, a,/barns: 180

•GEOLOGICAL Minerals Although present in uranium minerals, none is extracted from this source. Neptunium-237 is obtained in kg quantities from uranium fuel elements where it is produced by neutron capture: 2iRU + n -+239U (p emission) ->237Np. Specimen: commercially available, under licence

- see Key.

Abundances Sun (relative to H = 1 x 1012): n.a. Earth’s crust/p.p.m.: Neptunium is present

in minute quantities in uranium ores, and is formed when one of the emitted neutrons, from a uranium atom undergoing fission, is captured by another uranium nucleus. Seawater/p.p.m.: nil

137

Atomic number: 28 Relative atomic mass (,2C= 12.0000): 58.6934

CAS: [7440-02-0]

Description: Nickel is a silvery-white, lustrous, malleable and ductile metal. It resists

corrosion, but is soluble in acids (except concentrated HN03), yet unaffected by alkalis. It is used in alloys, especially stainless steel, in coins, metal plating, and catalysts. Radii/pm: Ni3+ 62; Ni2+ 78; atomic 125; covalent 115 Electronegativity: 1.91 (Pauling); 1.75 (Allred); 4.40 eV (absolute) Effective nuclear charge: 4.05 (Slater); 5.71 (dementi); 7.86 (Froese-Fischer)

Standard reduction potentials /T7V VI

IV >

II

1.6

acid

[Ni04]2“

Ni02

base

[Ni04]2- >0'4

Ni02

1:593

Ni2+-Ni Ni(OH)2 ~°'72

Ni

Oxidation states Nb1 Ni° Ni1 Ni"

d10s' d10 d9 d8

[Ni2(CO)6]2[Ni(CO)4],K4[Ni(CN)4] [NiBr(PPh3)3] NiO, Ni(OH)2, [Ni(OH2)6]2+ (aq), NiF2, NiCl2, etc., salts, K2[Ni(CN) M )/kJ mol-1: 156 Ionization energies/kj mol-1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M* M2+ M3* M4’ M5* M6+ M7+ M8t M9*

—> M+ M2‘ -» M3t —> M4+ —> M5* —> M6* -> M7+ -> M8+ -4 M9‘ -4 M104

736.7 1753.0 3393 5300 7280 10400 12 800 15 600 18 600 21660

Electron binding energies/eV

K L,

Is 2s

Lit

2Pl/2

Lib M, Mu Mm

2p3/2 3s

Main lines in atomic spectrum

[Wavelength/nm(species)] 232.003 (I) (AA) 341.476 (I) 349.296 (I) 351.505 (I) 352.454 (I) 361.939 (I)

8333 1008.6 870.0 852.7 110.8 68.0 66.2

3Pl/2 3P3/2

•CRYSTAL Crystal structure (cell dimensions/pm), space group

f.c.c. (a= 352.38), Fm3m ‘hexagonal’ nickel (an impure form of nickel) (a = 266, c = 432), P6,/mmc X-ray diffraction: mass absorption coefficients [p/p)l cm2 g-1: CuK(< 45.7 MoKa 46.6 Neutron scattering length, h/10 12 cm: 1.03 Thermal neutron capture cross-section, M+

642

Electron binding energies/eV

Main lines in atomic spectrum

n.a.

[Wavelength/nm(species)] n.a.

•CRYSTAL Crystal structure (cell dimensions/pm), space group

n.a. X-ray diffraction: mass absorption coefficients (p/p)/cm2 g-1: CuKa n.a. MoKu n.a. Neutron scattering length, fo/10-12 cm: n.a. Thermal neutron capture cross-section, cr,/barns: n.a.

•GEOLOGICAL Minerals Not found on Earth.

Chief source: atoms of nobelium were originally

Abundances

made one-at-a-time by bombarding 246Cm with 12C nuclei, although it is now possible to make several thousand atoms within 10 minutes by bombarding 249Cf with l2C.

Sun (relative to H = 1 x 10'2): n.a. Earth’s crust/p.p.m.: nil Seawater/p.p.m.: nil

Specimen: not available commercially

145

Atomic number: 76 Relative atomic mass (12C = 12.0000): 190.23

•CHEMICAL

CAS: [7440-04-2]

DATA

Description: Osmium is a lustrous, silvery metal of the so-called platinum group. It is

unaffected by air, water, and acids, but dissolves in molten alkalis. Osmium metal gives off a recognizable smell due to the formation of volatile osmium tetroxide, OsO.,. The metal is used in alloys and catalysts. Radii/pm: Os4* 67; Os3* 81; Os2* 89; atomic 135; covalent 126 Electronegativity: 2.2 (Pauling); 1.52 (Allred); 4.9 eV (absolute) Effective nuclear charge: 3.75 (Slater); 10.32 (Clementi); 14.90 (Froese-Fischer)

Standard reduction potentials E7V VIII

IV

III

II

0

_0.85 ^

0.687

1.005

1

-Os

Os04-Os02[OsClef-^lOsCle]3[Os(CN)4(OH)2]3-

[Os(CN)4(OH)2]

Oxidation states [Os(CO)4]2" [Os(CO)5], [Os2(CO)9], [Os3(CO)12] Osl OsCl2, OsI2 OsCl3, OsBr3, OsI3, complexes

O

d10 d8 d7 d6 d5

>

Os 11 Os° Os' Os11 Osm

Osv Os'1 Os'11 Os'™

d4 d3 d2 d1 d°[f14]

Os02, Os02 (aq), OsF4, OsCL,, OsBr4, [OsCy2-, complexes OsF5, OsC15 Os03?, OsF6 OsF7 Os04, [0s04(0H)2]2' (aq)

•PHYSICAL Melting point / K: 3327

AW fusion/kj mol'1: 29.3

Boiling point/K: 5300

Thermodynamic properties (298.15 K, o.l MPa) State Solid Gas

AfhP/kJ mol'1 0 791

AfG*7kJ mol'1 0 745

S*/J K 1 mol'1 32.6 192.573

C„/J K'1 mol'1 24.7 20.786

Density/kg m'3: 22 590 [293 K]; 20 100 [liquid at m.p.]

Young’s modulus/GPa: 559

Molar volume/cm3: 8.43

Rigidity modulus/GPa: 223

Thermal conductivity/W m'1 K"1: 87.6 [300 K]

Bulk modulus/GPa: 373

Coefficient of linear thermal expansion/K'1:4.3 x KT6 (a axis);

Poisson’s ratio/GPa: 0.25

6.1 x KT6 (b axis); 6.8 x KT6 (c axis) Electrical resistivity /Q m: 8.12 x 10~8 [273 K] Mass magnetic susceptibility/kg'1 m3: +6.5 x 10'10 (s)

•BIOLOGICAL

A T A

Biological role

Levels in humans

None.

Organs:

Toxicity

Daily dietary intake:

The metal itself is not toxic but its volatile oxide, Os04, is. Toxic intake: oxide, inhalation, human = 133 pg m'3 Lethal intake: LD50 (oxide, oral, rat) = 162 mg kg'1

Hazards Osmium dust is an irritant to eyes, skin and mucous membranes.

n.a., but low n.a.

Total mass of element in average (70 kg) person:

n.a., but very low

Discovered in 1803 by S. Tennant at London, England.

Osmium

[Greek, osme = smell I French, osmium; German, Osmium; Italian, osmio; Spanish, osmio

[oz-mi-uhm]

•NUCLEAR Number of isotopes (including nuclear isomers): 37

Isotope mass range: 166 -> 196

Key isotopes Nuclide

Atomic mass

Natural abundance(%)

Nuclear spin I

Nuclear magnetic Uses moment p

'“Os

183.952488

0.02

Ot

E

'“OS*

185.953 830

1.58

Of

E

l870s

186.955 741

1.6

18»Os

187.955830

13.3

Of

l890s

188.958 137

16.1

3/2+

,wOs

189.958 436

26.4

Of

E

1920s

191.961467

41.0

Of

E

1/2-

+0.064 651

E, NMR E

+0.659933

E, NMR

*l86Os is radioactive with a half-life of 2 x 10'5 y and decay mode a. A table of radioactive isotopes is given in Appendix 1, on p246.

1870s 1.22 x 10"5 0.00114 0.6105 xlO7

NMR [Reference: 0s04] Relative sensitivity (1H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T 1 s4 Nuclear quadrupole moment/m2

2.282

Frequency (‘H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

,89Os 2.34x1 O'3 2.13 2.0773 x 107 +0.856 xlO"28 7.758

DATA

Ground state electron configuration: [Xe]4fl45d66s2 Term symbol: 5D4 Electron affinity (M -> M )/kJ mol"1: 106 Ionization energies/kj mol"1:

1. 2. 3. 4. 5. 6. 7. 8.

M M’ M2+ M3+ M4t M5+ M6* M7*

—> —> —>

—> -> —»

M’ M2+ M3’ M4t M5* Mr,+ M7+ M8*

840 (1600) (2400) (3900) (5200) (6600) (8100) (9500)

Electron binding energies/eV 73 871 Is K

L, hi,M, hi

M„ Mra M1V Mv

2s

Main lines in atomic spectrum

[Wavelength/nm(species)] 201.015 (I) 201.814 (I) 202.026 (I) 203.444 (I) 204.536 (I) 290.906 (I) (AA)

12 968 12 385 10 871 3049 2792 2457 2031 1960

2Pl/2 2P3/2

3s 3Pl/2 3P3,2

3d3;2 3d5/2

continued in Appendix 2. p256

•CRYSTAL Crystal structure (cell dimensions/pm), space group

h.c.p. (a = 273.43, c= 432.00), P63/mmc X-ray diffraction: mass absorption coefficients (p/p)/cm2 g"1: CuKa 186 MoKa 106 Neutron scattering length, bl 10"12 cm: 1.07 Thermal neutron capture cross-section, p) =23.8K T(p->y) = 43.8 K X-ray diffraction: mass absorption coefficients [p/p) I cm2 gCuK„ 11.5 MoKa 1.31 Neutron scattering length, b/10-12 cm: 0.5803 Thermal neutron capture cross-section, cr,/barns: 0.00019

•GEOLOGICAL

DATA

Minerals Oxygen is the most abundant element on tire surface of the Earth, occurring as oxygen gas in the atmosphere, water in the oceans, and in minerals as oxides, or in combination with other elements as silicates, carbonates, phosphates, sulfates, etc.

Chief source: liquid air World production / tonnes y-1: 1 x 108 Reserves/tonnes: 1.2xl015 (in atmosphere)

Abundances Sun (relative to H = 1 x 1012): 6.92 x 108 Earth’s crust/p.p.m.: 474 000

Specimen: available in small pressurized

Atmosphere/p.p.m. (volume): 209 500 Seawater/p.p.m.: constituent element of

canisters. Safe, but be aware of possible dangers.

water

149

'

Atomic number: 46 Relative atomic mass (I2C= 12.0000): 106.42

Y 'H

t

CAS: [7440-05-3]

•CHEMICAL Description: Palladium is a lustrous, silvery-white, malleable and ductile metal of the

so-called platinum group. It resists corrosion, but dissolves in oxidising acids and in molten alkalis. Palladium metal has the unusual ability of allowing hydrogen gas to filter through it. It is mainly used as a catalyst. Radii /pm: Pd4+ 64; Pd2+ 86; atomic 138; covalent 128 Electronegativity: 2.20 (Pauling); 1.35 (Allred); 4.45 eV (absolute) Effective nuclear charge: 4.05 (Slater); 7.84 (dementi); 11.11 (Froese-Fischer)

Standard reduction potentials £"7 V VI

IV

acid base

II

0

Pd02 ----- Pd2+-Pd ‘Pd03’

2~°3- Pd02

Pd(OH)2 ~019

Pd

Oxidation states Pd° Pd"

d10 d8

Pdiv

d6

[Pd(PPh3)3], [Pd(PF3)4] PdO, [Pd(OH2)4]2+ (aq), PdF,, PdCl2 etc., [PdCl4]2', salts, complexes Pd02, PdF4, [PdCl6]2'

•PHYSICAL

DATA

Melting point/K: 1825

Aff fusion /kj mol ‘: 17.2

Boiling point / K: 3413

AWvap/kJ mol'1: 393.3

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

AfH*7kJ mol'1 0 378.2

AfG®/kJ mol' 0 339.7

Density/kg m'3: 12 020 [293 K|; 10 379 [liquid at m.p.]

S9/J K'1 mol'1 37.57 167.05

C„/J K'1 mol'1 25.98 20.786

Young’s modulus/GPa: 121

Molar volume/cm3: 8.85

Rigidity modulus/GPa: 43.6

Thermal conductivity/W m'1 K'1: 71.8 [300 K]

Bulk modulus/GPa: 187

Coefficient of linear thermal expansion/K'1: 11.2x 10"6

Poisson’s ratio/GPa: 0.39

Electrical resistivity/Q m: 10.8 x 10~8 [293 K] Mass magnetic susceptibility/kg'1 m3: +6.702 x lO'8 (s)

G I C A L

DATA

Biological role

Levels in humans

None.

Organs:

Toxicity

Daily dietary intake:

Toxic intake: n.a. Lethal intake: LD50 (chloride, oral, rat) =

25 mg kg'1

Hazards Palladium is poorly absorbed by the body when ingested and PdCl2 was formerly prescribed as a treatment for tuberculosis at the rate of 65 mg per day (approximately 1 mg kg'1) without apparent ill effects. Palladium at higher intakes is poisonous and is an experimental carcinogen.

150

n.a. but very low n.a.

Total mass of element in average (70 kg) person:

n.a.

Discovered in 1803 by W.H. Wollaston at London, England.

Palladium

(Named after the asteroid Pallas) French, palladium-, German, Palladium-, Italian, palladio; Spanish, paladin

•NUCLEAR

Ipal-ayd-iuhm]

DATA

Number of isotopes (including nuclear isomers): 25

Isotope mass range: 96 -»116

Key isotopes Nuclide

Atomic mass

“Pd

101.905 634

1.02

“Pd

103.904029

11.14

“Pd l°6pd

104.905 079

22.33

Of 5/2+

105.903 478

27.33

0+

E

“Pd UOpd

107.903 895

26.46

Of

E

109.905 167

11.72

Of

E

Natural abundance (%)

Nuclear spin J

Nuclear magnetic Uses moment p

Of

E E -0.642

E, NMR

A table of radioactive isotopes is given in Appendix 1, on p246.

NMR [OnlyK2PdCl6 recorded]

tospd

Relative sensitivity ('H = 1.00) Receptivity (13C = 1.00)

1.12 xlO3 1.41

IVIagnetogyric ratio/rad T ‘s'

-0.756 xlO7

Nuclear quadrupole moment/m2

+0.660 x 10~28 4.576

Frequency (‘H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

D A T A

Ground state electron configuration: [Kr]4d10 Term symbol: 'S0 Electron affinity (M ^ M )/kJ mob1: 53.7 Ionization energies/kj mol 1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M4 M2+ M34 M‘1+ M5+ M64 M7+ M8+ M94

-f -> -> -» -+ -+ -> -+ -> -f

M4 M24 M34 M4+ M54 M64 M74 M84 M9+ M104

Main lines in atomic spectrum

Electron binding energies/eV

805 1875 3177 (4700) (6300) (8700) (10 700) (12 700) (15 000) (17 200)

K L, L„ La, M, M„ Mm M„ Mv continued

Is 2s 2p,/2 2P3/2

3s 3p,,2 3P3/2 3d3,2 3d5/2

in

[Wavelength/nm(species)] 247.642 (I) (AA)

24 350 3604 3330 3173 671.6 559.9 532.3 340.5 335.2

340.458 (I)

342.124 (I) 351.694 (I) 355.308 (I) 360.955 0) 363.470 (I)

Appendix 2, p256

•CRYSTAL-DATA Crystal structure (cell dimensions/pm), space group

f.c.c. (a = 389.08), Fm3m X-ray diffraction: mass absorption coefficients [p/p)l cm2 g ': CuK,, 206 MoKa 24.1 Neutron scattering length, bl 1012 cm: 0.591 Thermal neutron capture cross-section, M )/kJ mol1: 205.3 Ionization energies/kj mol”1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M* M2+ M3+ M5+ M6+ M7* M8+ M9+

-+ -+ -+ -» -+ -+ -+ -+ ^ ^

870 M+ 1791 M2+ (2800) M3+ (3900) M4+ (5300) M5+ (7200) M6" (8900) M7+ M8* (10 500) M9+ (12 300) M10+ (14 100)

•CRYSTAL

Electron binding energies /eV

K

Li Lu

Lm M, M„ Mm Mw Mv

Is 2s 2pw2 2p3/2 3s

Main lines in atomic spectrum

[Wavelength / nm (species) ] 204.937 (I) 208.459 (I) 214.432 (I) 265.945 (I) (AA) 270.240 ffi 299.767 (I) 306.471 (I)

78 395 13 880 13 273 11564 3296 3027 2645 2202 2122

3Pl/2

3p3/2 3d3/2 3d5/2

continued in Appendix 2, p256

DA T A

Crystal structure (cell dimensions/pm), space group

f.c.c. {a = 392.40), Fm3m X-ray diffraction: mass absorption coefficients (/z/p) / cm2 g”1: CuK0 200 MoKa 113 Neutron scattering length, £>/10”12 cm: 0.960 Thermal neutron capture cross-section, rra/barns: 10.3

•GEOLOGICAL

DATA

Minerals Nadve platinum occurs naturally. Mineral Formula Platiniridium (Ir,Pt) Platinum Pt

Density 22.7 c. 21

Hardness 6-7 4-4.5

Crystal appearance cub., met. white cub., metallic white/grey

Chief ores: platinum ore; some platinum is

Abundances

extracted as a by-product of copper and nickel refining.

Sun (relative to H = 1

World production/tonnes y'1:30

x

1012): 56.2

Earth’s crust/p.p.m.: c. 0.001 Seawater/p. p.m.:

Atlantic surface: n.a. Atlantic deep: n.a. naturally, mostly as nuggets, in the rivers of the Pacific surface: 1.1 x 10”7 Urals in Russia, and in deposits in Canada, Pacific deep: 2.7 x 10”7 South Africa, Columbia and Peru. Residence time/years: n.a. Reserves/tonnes: n.a. Oxidation state: II Specimen: available as foil, gauze, sponge, powder or wire. Safe. Main mining areas: native platinum occurs

155

Atomic number; 94 Relative atomic mass (12C= 12.0000): 244.0642 (Pu-244)

•CHEMICAL

CAS: [7440-07-5]

DATA

Description: Plutonium is a silvery, radioactive metal which occurs naturally in minute

amounts in uranium ores. It is attacked by oxygen, steam and acids, but not alkalis. The metal is produced by reacting PuF3 with either lithium or barium at 1200 °C. A piece of plutonium is warm to the touch because of the energy given off by the a-decay. Plutonium can be used as a nuclear explosive or as a nuclear fuel; 1 kg of plutonium produces an explosion equivalent to 20 000 tonnes of TNT. Plutonium was used on the Apollo flights to power seismic devices and other equipment left on the Moon. Radii/pm: Pu6+ 81; Pu5* 87; Pu4* 93; Pu3+ 108 Electronegativity: 1.28 (Pauling); 1.22 (Allred); n.a. (absolute) Effective nuclear charge: 1.65 (Slater)

Standard reduction potentials E^IV VII

VI

V

IV

III

1.03

acid

PuO

,

o_

base

1.02

2+

u.yo

-1.25

PuO,

u.j

1.04

Pu

1.01

4+

Pu-3+

u.y

[Pu05r -[Pu2(OH)3]_ — Pu(OH)02-Pu02 -

Pu(OH)3

1.584

2.46

Pu Pu

Oxidation states Pu" Pu"1

f f

PuO, PuH2 Pu203, PuF3, PuCl3 etc., [Pu(OH2)x]3+ (aq), Pu3+ salts, complexes, [Pu(C5H5)3] Pu,v f Pu02, PuF4, [PuC16]z_, [Pu(OH,)x]4+ (aq) unstable, complexes Mixed valence oxide: Pu305

Puv f Pu" e Puv" f1

Pu02+ (aq) unstable , CsPuF6 Pu022+ (aq), PuF6 Li5Pu06, [Pu05]3 (aq)

•PHYSICAL A«* /kj mol': 2.8 AW,ap/kj mol 343.5

Melting point /K: 914 Boiling point/K: 3505

Thermodynamic properties (298.15 K, o.l MPa) State Solid Gas

Affr/kJ mol1 0 n.a.

AfGe/kJ mol1 0 n.a.

S*/J K 1 mol"1 n.a. n.a.

C,,/J K 1 mol n.a. n.a.

Density/kg m 3: 19 840 (a) [298 K]; 16 623 [liquid at m.p.]

Young’s modulus/GPa: 87.5

Molar volume/cm3: 12.3

Rigidity modulus/GPa: 34.5

Thermal conductivity/W m 1 K :: 6.74 [300 K]

Bulk modulus/GPa: n.a.

Coefficient of linear thermal expansion/K ‘: 55 x 104'

Poisson’s ratio/GPa: 0.18

Electrical resistivity In m: 146 x 10 8 [273 K] Mass magnetic susceptibility/kg 1 m3: +3.17 x 10-8 (s)

• B I

m

L

G I C A L

Biological role

Levels in humans

None.

Organs:

Toxicity

Daily dietary intake:

The very high r idiotoxicity of plutonium overrides any o her toxicity considerations.

Hazards Never normally encountered outside the laboratory or nuclear industry, but is highly dangerous because of its intense radioactivity. Inside the human body the element tends to accumulate in bone marrow and there it is highly dangerous because of the a-particles it emits. The permitted levels of plutonium are the lowest of any of the radioactive elements.

156

n.a., but extremely low nil

Total mass of element in average 170 kgl person:

n.a., but extremely low

Discovery: see Nuclear Data section.

Plutonium

[Named after the planet Pluto] French, plutonium-, German, Plutonium; Italian, plutonio; Spanish, plutonio

[ploo-toh-nee-uhm|

• NUCLEAR Discovery: Plutonium was discovered in 1940 by G.T. Seaborg, A.C. Wahl and J.W. Kennedy at

Berkeley, California, USA. Number of isotopes (including nuclear isomers): 15

Isotope mass range: 232 -> 246

Key isotopes Nuclide

Atomic mass

Half life (T„2) Decay mode and energy (MeV)

Nuclear Nucl. mag. Uses spin I moment u

234pu

234.043 299

8.8 h

EC (0.38) 94%; a (6.310) 6%; no y

0+

236pu

236.046032

2.87y

a (5.867); no y

0+

23’pu

237.048401

45.2 d

EC (0.22) 99.9%; a (5.747) 0.03%; y

7/2-

238pu

238.049 554

87.74 y

a (5.593); y

0+

239pu

239.052 157

24 llOy

a (5.244); y

1/2+

299%; a (5.139) 0.02%; y

5/2+

242pu

242.058737

3.76 x 105y 4.956 h

a (4.983); y

Of

p~ (0.582); y

7/2+

a (4.665) 99.9%; SF 0.1%; y

Of

P‘ (1-28); y

9/2-?

p- (0.40); y

Of

243pu

243.061 998

244pu

244.064 199

245pu

245.067820

8.2 xl07y 10.5 h

246pu

246.070 171

10.85 d

+0.203

NMR

-0.683

Other isotopes of plutonium have half-lives shorter than 1 hour. 239pu

NMR [Reference: n.a.]

241pu

Relative sensitivity ('H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T 's'

0.972 x 107 5.600 x 1(T28

Nuclear quadrupole moment/m2 Frequency (*H = 100 Hz; 2.3488T)/MHz

•ELECTRON

3.63

SHELL

Ground state electron configuration: [Rn]5f67s2 Term symbol: 7F0 Electron affinity (M -> M')/kJ mol1: n.a. Ionization energies/kj mol-1:

1. M

-> M+

585

•CRYSTAL Crystal structure

Electron binding energies/eV

Main lines in atomic spectrum

n.a.

[Wavelength/nm(species)] 321.508 (I) 324.416 (I) 325.208 (I) 327.524 (1) 329.256 (I) 329.361 (I) 329.691 (I)

DATA

(cell dimensions/pm), space group

a-Pu monoclinic (a = 618.3, b = 482.2, c= 1096.3; 0= 101.79°), P21m ,3-Pu monoclinic (a = 928.4, b= 1046.3, c= 758.9;/3= 92.13°), I2/m y-Pu orthorhombic (a = 315.87, b - 576.82, c= 1016.2; /)= 92.13°), Fddd 5-Pu f.c.c. (a = 463.71), Fm3m y) = 473 K; T{j-> 8) = 583 K; T(S^ S') = 725 K; T{8' ^>e)= 753 K X-ray diffraction: mass absorption coefficients (p/p)/cm2 g ’: CuKa n.a. MoKa n.a. Neutron scattering length, £>/10"12 cm: 0.77 (2 ; 'Pu) Thermal neutron capture cross-section, 239U (p emission) -> 239Np (p emission) ^ 239Pu.

Sun (relative to H = 1 x 1012): n.a.

World production/tonnes y1:20

Reserves/tonnes: >500 Specimen: commercially available, under licence

- see Key.

Earth’s crust/p.p.m.: plutonium is present in minute quantities in uranium ores, and is formed when one of the emitted neutrons, from a uranium atom undergoing fission, is captured by another uranium nucleus which then undergoes |3-emission to give first neptunium, then plutonium. Seawater/p.p.m.: nil

157

Po

Atomic number: 84 Relative atomic mass (12C = 12.0000): 208.9824 (Po-209)

CAS: [7440-08-6]

Description: Polonium is a reactive, silvery-grey metal that dissolves in dilute acids. It is fairly volatile and about half will evaporate within two days if kept at 55 °C. A gram capsule of polonium will reach 500 °C because of the intense a-radiation, and for this reason polonium is used as a lightweight heat supply for space satellites. It is also used as a source of a-radiation for research. Radii/pm: Po4+ 65; Po2' 230; atomic 167; covalent 153 Electronegativity: 2.0 (Pauling); 1.76 (Allred); 5.16 eV (absolute) Effective nuclear charge: 6.95 (Slater); 14.22 (Clementi); 18.31 (Froese-Fischer)

Standard reduction potentials HlV TV

II

IV

0

-II

0.73 1.51

acid

_

_

1.1

_ 2+

PoOs-Po02-Po

0.37

_

c. -1.0

Po-PoHo

1.3 0.16 1.48

base

Po03-[Po03]

2-

-0.5

c. -1.4

Oxidation states

Covalent bonds

Po'11 Po" Po"

[Rn] s2p2 s2

Bond Po—Cl Po—Po

Po"

d10

H2Po, Na2Po PoO, PoCl2, PoBr2 Po02, [Po03]2' (aq), PoCl4, PoBri, PoI4, [PoI6]2' Po03 ?, PoF6

•>

Po-Po^

r/ pm 238 335

E/ kj mol' n.a. n.a.

•PHYSICAL Melting point/K: 527

mol 10 AHvap/kJ mol'1: 100.8

Boiling point/K: 1235

Thermodynamic properties (298.15 K,0.l MPa) State Solid Gas

AfH' /kJ mol'1 0 146?

AfG^/kJ mol"1 0 n.a.

S 218

Key isotopes Nuclide

Atomic mass

Half life (T„2) Decay mode and energy (MeV)

Nuclear Nucl. mag. Uses spin 1 moment p

».p0

203.980280

3.53 h

EC (2.4); y

0+

2or,p0

205.980456

8.8 d

EC (1.85) 95%; a 5%; y

0+

207po

206.981570

5.80 h

EC; p* (2.91); y

5/2-

208po

207.981222

2.898 y

a (5.213); y

0+

2®p0

208.982 404

102 y

a (4.976); y

1/2-

2I0po«

209.982 848

138.38 d

a (5.407); y

0+

21'PO*

210.986627

0.516 s

a (7.594); y

9/2+

2I6p0»

216.001 889

0.145 s

a (6.906); no y

0+

3.04 m

a (6.114); no y

0+

21«p0«

+0.79 +0.77

R tracer, fuel

•Traces of these isotopes occur naturally. Other isotopes of polonium have half-lives shorter than 2 hours.

NMR [Reference: not reported]

Magnetogyric ratio/rad T1 s1

209Po 7.4 x 107

Nuclear quadrupole moment/m2

-

Frequency ('H = 100 Hz; 2.3488T)/MHz

28

Relative sensitivity ('H = 1.00) Receptivity (13C= 1.00)

•ELECTRON

SHELL

Ground state electron configuration: [Xe]4f145d106s26p4 Term symbol: 3P2 Electron affinity (M -> M )/kJ mol ': 183 Electron binding energies / eV

Ionization energies/kj mol ':

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M —> M4 M4 —> M24 M2+ —> M34 m4+ M3* M44 -> M54 M5’ —> M64 M74 M84 M74 M84 M34 M34 —> M104

812 (1800) (2700) (3700) (5900) (7000) (10 800) (12 700) (14 900) (17 000)

•CRYSTAL

K L, Lb Lm M, Mb Mm Mn Mv

93 105 16 939 16 244 13 814 4149 3854 3302 2798 2683

Is 2s 2Pl/2 2P3/2 3s 3pu2 3p3/2 3d3/2 3d5/2

Main lines in atomic spectrum

[Wavelength/nm(species)] 245.008 (I) 255.801 (I) 300.321 (I) 417.052 (I)

continued in Appendix 2, p256

DATA

Crystal structure (cell dimensions/pm), space group

a-Po cubic (a = 335.2), Pm3m /3-Po rhombohedral (a = 336.6, T(a->p) = 309 K

a

= 98° 13'), R3m

X-ray diffraction: mass absorption coefficients (/i/p)/cm2 g ': CuK„ n.a. Neutron scattering length, bl 10 12 cm: n.a. Thermal neutron capture cross-section, cr,/barns: < 0.03 (2l0Po)

•GEOLOGICAL

MoK„ n.a.

DATA

Minerals Uranium ores contain about 100 x 10~6 g of polonium per tonne, and Mme. Curie obtained the first sample of the element from this source. Polonium-210 is made in g quantities by bombarding bismuth with neutrons. World production: n.a. but probably c. 100 g per

Abundances

year.

Sun (relative to H = 1 x 1012): n.a.

Specimen: commercially available, under licence

Earth’s crust/p.p.m.: traces in uranium ores Seawater/p.p.m.: nil

- see Key.

159

Atomic number:

CAS: [7440-09-7]

19

Relative atomic mass (12C= 12.0000): 39.0983

• C H

I C A L

Description: Potassium is a soft white metal which is silvery when first cut but oxidizes

rapidly in air. It reacts violently with water. Potassium is obtained from the reaction of sodium metal with potassium chloride. The metal itself is little used, but potassium compounds are important in fertilizers, chemicals and glass. Radii/pm: K+ 133; atomic 227; covalent 203; van der Waals 231 Electronegativity: 0.82 (Pauling); 0.91 (Allred); 2.42 eV (absolute) Effective nuclear charge: 2.20 (Slater); 3.50 (Clementi); 4.58 (Froese-Fischer)

Standard reduction potentials E^IV I KH

o -2.924

K

Oxidation states K"1

s2 [Ar]

K1

solution in liquid ammonia K20, K202 (peroxide), K02 (superoxide), K03 (ozonide), KOH, [K(OH2)4]+ (aq), KH, KF,KC1 etc., r salts, K2C03,complexes, [K(18-crown-6)]+

Melting point/K: 336.80

AH^^Ik] mol ': 2.40 AWvap/kJ mol"1: 77.53

Boiling point/K: 1047

Thermodynamic properties (298.15 K, o.l MPa) State Solid Gas

mol1 0 89.24

AfG*7kJ mol"1 0 60.59

SVJ K"1 mol1

C„/J K 1 mol"1

64.18 160.336

29.58 20.786

Density/kg m"3: 862 [293 K[; 828 [liquid at m.p.]

Young’s modulus/GPa: 3.53 [83 K]

Molar volume/cm3: 45.36

Rigidity modulus/GPa: 1.30

Thermal conductivity/W m"1 K"1: 102.4 [300 K]

Bulk modulus/GPa: n.a.

Coefficient of linear thermal expansion /K"1:83 x 10"6

Poisson’s ratio/GPa: 0.35 [83 K[

Electrical resistivity/f2 m: 6.15 x 10"8 [273 K] Mass magnetic susceptibility/kg"1 m3: +6.7 x 10"9 (s)

BIOLOGICAL Biological role

Levels in humans

Essential to all living things.

Blood/mg dm"3:1620

Toxicity

Bone/p.p.m.: 2100

Toxic intake: KC1 = c. 4 g

Liver/p.p.m.: 16 000 Muscle/p.p.m.: 16 000

Lethal intake: LD50 (chloride, oral rat) =

Daily dietary intake: 1400 - 7400 mg

2600 mg kg"'

Total mass of element

Hazards

in average (70 kg) person: 140 g

The toxicity of potassium compounds is almost always that of the anion, not of the K*. However, although KC1 is often used as a nutrient or dietary supplement, there are rare cases of excess ingestion by humans proving fatal.

160

Isolated in 1807 by Sir Humphry Davy at London, England.

__

[English, potash-, Latin, kalium]

P0l3SSIUIfl

French, potassium; German, Kalium; Italian, potassio; Spanish, potasio

• N U fr l E A R

.

[poh-tass-ium|

DATS

Number of isotopes (including nuclear isomers): 18

Isotope mass range: 35 -> 51

Key isotopes Nuclide

Atomic mass

Natural abundance

(%)

Nuclear spin I

Nuclear magnetic Uses moment p

39K

38.963707

93.258 1

3/2+

+0.391465

E, NMR

40K *

39.963999

0.011 7

4-

-1.298009

E

41K

40.961825

6.7302

3/2+

+0.214869

E. NMR

40K is radioactive with a half-life of 1.25 x 109y and decay mode B~ (1.32 MeV); EC; A table of radioactive isotopes is given in Appendix 1, on p247.

40K

NMR [Reference: K+ (aq)]

39K

Relative sensitivity (‘H = 1.00)

5.08 X Iff4 2.69 1.2483 xlO7 0.0601 x 10“28 4.667

Receptivity (13C = 1.00) Magnetogyric ratio/rad T"1 s'1 Nuclear quadrupole moment/m2 Frequency (‘H = 100 Hz; 2.3488T)/MHz

y.

4iK

-0.0749 x 10“28

8.40 x 10-4 0.0328 0.6851 x 10' 0.0733x10 2.561

Ground state electron configuration: [Ar]4s‘ Term symbol: 2S1/2 Electron affinity (M -> M“)/kJ mol'1: 48.4 Ionization energies/kj mol'1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M4 M24 M34 M4* M54 Ms+ M7* M84 M9+

-+ -+ -+ -+ -+ -+ -> -+ -» -+

M4 M2+ M3+ M44 M54 M6' M7t M84 M94 M104

Electron binding energies/eV

418.8 3051.4 4411 5877 7975 9649 11343 14942 16964 48575

•CRYSTAL

Is 2s 2Pl/2 2p3/2 3s 3Pl/2 3P3/2

K Li

u I+n M, M„ Mm

3608.4 378.6 297.3 294.6 34.8 18.3 18.3

Main lines in atomic spectrum

[Wavelength / nm (species)] 404.414 (I) 691.108 (I) 693.877 (I) 766.491 (I) 769.896 (I)

D A T A

Crystal structure (cell dimensions/pm), space group

b.c.c. (a = 533.4), Im3m X-ray diffraction: mass absorption coefficients (p/p)/cm2 g ': CuK„ 143 MoKa 15.8 Neutron scattering length, bl 1(T12 cm: 0.367 Thermal neutron capture cross-section, a,/bams:2.1

•GEOLOGICAL

DATA

Minerals Potassium occurs in many minerals. Mineral Alunite Carnallite Orthoclase* Sylvite

Formula KA13(S04)2(0H)6 KCl.MgCl,.6H20 KAlSi308 KC1

Density Hardness Crystal appearance 3.5-4 rhom., vit. white/grey 2.69 1.602 2.5 orth., greasy colourless-red 2.563 6-6.5 mon., vit. colourless/white 1.993 2 cub., vit. colourless/white

*Mined on a large scale for porcelain, ceramics and glass. Chief ores: sylvite, carnallite, alunite World production/tonnes y"1: 200 (potassium

metal); 51 x 106 (potassium salts) Main mining areas: Germany, Spain, Canada, USA, Italy

Abundances Sun (relative to H = 1 x 1012): 1.45 x 105 Earth’s crust/p.p.m.: 21 000 Residence time /years: 5 x 10li Classification: accumulating Oxidation state: 1

Reserves/tonnes: vast, > 1 x 1010 Specimen: available as chunks (in mineral oil) or

ingots (in ampoules). Warning!

161

Atomic number. 59 Relative atomic mass (12C = 12.0000): 140.90765

CAS: [7440-10-0]

Description: Praseodymium is a soft, malleable, silvery metal of the so-called rare earth group

(more correctly termed the lanthanides). It reacts slowly with oxygen, and rapidly with water. Praseodymium is used in alloys for permanent magnets and flints. It is used to make the yellow glass for eye protection for welders, etc. Radii/pm: Pr4* 92; Pr3’ 106; atomic 183; covalent 165 Electronegativity: 1.13 (Pauling); 1.07 (Allred); < 3.0 eV (absolute) Effective nuclear charge: 2.85 (Slater); 7.75 (dementi); 10.70 (Froese-Fischer)

Standard reduction potentials ElV TV 4,

III 3.2

o.

0 -2.35

acid

Pr4 -Pr3+-Pr

base

Pr02-Pr(OH)3-Pr

0.8

-2.79

Oxidation states Pr"1

f2

PrIV

fl

Pr203, Pr(OH)3, [PrlOHJJ3* (aq), Pr3+ salts, PrF3, PrCl3 etc., complexes Pr02, PrF4, Na2PrF6

Melting point/K: 1204

mol 11.3 AWvap/kJ moP1: 332.6

Boiling point/K: 3785

Thermodynamic properties (298.15 K, 0.1 MPa) State

Solid Gas

AfFT/kJ mol1 0 355.6

AfG®/kJ mol1 0 320.9

S/10“l2cm: 0.445 Thermal neutron capture cross-section, ffj/bams: 11.5

•GEOLOGICAL Minerals Mineral Bastnasite* Monazite*

Formula Density Hardness Crystal appearance (Ce,La, etc.)C03F 4.9 4-4.5 hex., vit. greasy yellow (Ce, La, Nd, Th, etc.)PO., 5.20 5-5.5 mon., waxy/vit. yellow-brown

‘Although not a major constituent, praseodymium is present in extractable amounts. Chief ores: monazite, bastnasite World production/tonnes y1:2400 Main mining areas: USA, Brazil, India, Sri Lanka, Australia Reserves/tonnes: c.2xl06 Specimen: available as chips, foil and ingots. Safe. Pr powder is a skin and eye irritant. Care!

Abundances Sun (relative to H = 1 x 1012): 4.6 Earth’s crust/p.p.m.: 9.5 Seawater/p.p.m.: Atlantic surface: 4 x 10'7 Atlantic deep: 7 x 10~7 Pacific surface: 4.4 x 10 7 Pacific deep: 10 x 10 7 Residence time/years: n.a. Oxidation state: III

163

Pm

Atomic number: 61

CAS:

Relative atomic mass (l2C= 12.0000): 144.9127 (Pm-145)

[7440-12-2]

•CHEMICAL Description: Promethium is a radioactive metal of the so-called rare earth group (more

correctly termed the lanthanides). It is used in specialized miniature batteries. Radii/pm: Pm3+ 106; atomic 181 Electronegativity: n.a. (Pauling); 1.07 (Allred); < 3.0 eV (absolute) Effective nuclear charge: 2.85 (Slater); 9.40 (Clementi); 10.94 (Froese-Fischer)

Standard reduction potentials ElV III O.

0 -2.29

acid

Pm3- Pm

base

Pm (OH) 3- Pm

-2.76

Oxidation states Pm1" f4

Pm203, Pm(OH)3, [Pm(OH2)J3+ (aq), PmF3, some complexes

•PHYSICAL

DATA

Melting point/K: 1441

AW^/kJ mol': 12.6 AWvap/kJ mol"1: n.a.

Boiling point/K: c. 3000

Thermodynamic properties (298.15 K, o.l MPa) State Solid Gas

AfFTVkl mol-1 0 n.a.

AfG®/kJ mol'1 0 n.a.

S9/J K'1 mol'1 n.a. 187.101

C„/J K'1 mol'1 26.8 24.255

Density/kg m 3: 7220 [298 K]

Young’s modulus/GPa: 46 (est.)

Molar volume/cm3: 20.1

Rigidity modulus/GPa: 18 (est.)

Thermal conductivity/W m 1 K"1: 17.9 (est.) [300 K]

Bulk modulus/GPa: 33 (est.)

Coefficient of linear thermal expansion IK"': 16 x 10"

Poisson’s ratio/GPa: 0.28 (est.)

Electrical resistivity In m: 50 x 10~8 (est.) [273 K] Mass magnetic susceptibility/kg'1 m3: n.a.

•BIOLOGICAL Biological role

Levels in humans

None.

Organs:

Toxicity

Daily dietary intake:

The radiotoxicity of promethium overrides other toxicity considerations.

Hazards Never normally encountered outside the laboratory or nuclear industry, but it is hazardous because of its radioactivity.

164

nil nil

Total mass of element in average (70 kg) person:

nil

Discovery: see Nuclear Data section.

Promethium

INamed after Prometheus of Greek mythology, who stole fire from the gods] French, promethium-, German, Promethium-, Italian, prometo; Spanish, prometio

•NUCLEAR

[proh-mee-thi-uhm]

DATA

Discovery: Promethium was produced in 1945 by J.A. Marinsky, L.E. Giendenin and

C.D. Coryell at Oak Ridge, Tennessee, USA. Number of isotopes (including nuclear isomers): 27

Isotope mass range: 134 -> 155

Key isotopes Nuclide

Atomic mass

141 Pm

140.913600

20.9 m

(3* (3.73) 52%; EC 48%; y

5/2+

'“Pm

142.910930

265 d

EC (1.042); y

5/2+

3.8

144Pm

143.912588

360 d

EC (2.333); y

5-

1.7

l45Pm

144.912743

17.7 y

EC (0.164); y

5/2+

146Pm

145.914708

5.53 y

EC (1.48) 63%; p-(1.54) 37%; y

3-

"’Pm

146.915 135

2.6234 y

P" (0.224); weaky

7/2+

+2.6

14“Pm

147.917473

5.37 d

p- (2.47); y

1-

+2.0

Half fife (T„2) Decay mode and energy (MeV)

Nuclear Nucl. mag. spin I moment p

41.3 d

p- (2.6); 95%; IT (0.137) 5%; y

6-

1.8

"’Pm

148.918332

2.212 d

p-(1.073); y

7/2+

3.3

l50Pm 151 Pm

149.920981 150.921 203

2.68 h 1.183d

P- (3.45); y P-(1.197); y

1-? 5/2+

+1.8

148mPm

Other isotopes of promethium have halfdives shorter than 10 minutes.

NMR [Reference: not recorded]

Magnetogyric ratio/rad T-1s-1

147Pm 3.613 x 107

Nuclear quadrupole moment/m2

-

Frequency (*H = 100 Hz; 2.3488T)/MHz

13.51

Relative sensitivity (’H = 1.00) Receptivity (13C = 1.00)

•ELECTRON

SHELL

DATA

Ground state electron configuration: [Xe]4f'6s2 Term symbol: 6H5/2 Electron affinity (M -> M-)/kJ mol-1: < 50 Ionization energies/kj mol-1:

1. 2. 3. 4. 5.

M M* M2+ M3* M4+

-> -+ -> -+ ->

M* M2+ M3+ M4+ M5+

535.9 1052 2150 3970 5953

Electron binding energies/eV

Is

K L,

2s

Lu

2Pl/2

Em M, Mn

2P3/2

Mm

3P3/2

Mw My

3d3/2 3d5/2

45184 7428 7013 6459

3s

-

1471.4 1357 1052 1027

3Pl/2

Main lines in atomic spectrum

[Wavelength / nm (species) ] 389.215 (11) 391.026 (II) 391.910(11) 395.774 (II) 399.896 (II) 441.796 (II)

continued in Appendix 2, p257

•CRYSTAL

DATA

Crystal structure (cell dimensions/pm), space group

hexagonal X-ray diffraction: mass absorption coefficients (p/p)/cm2 g-1: CuKa 386

MoK„ 55.9

Neutron scattering length, bl 10-12 cm: 0.126 Thermal neutron capture cross-section, [$) = 1440 K X-ray diffraction: mass absorption coefficients (/i/p) / cm2 g'1: CuKa n.a.

MoKa n.a.

Neutron scattering length, bl 10"12 cm: 0.91 (231 Pa) Thermal neutron capture cross-section, o-a/barns: 200.6 (23lPa)

•GEOLOGICAL Minerals “‘Pa is a short-lived member of the 238U decay series and so occurs naturally in uranium ores such as pitchblende, to the extent of 3 p.p.m. in some ores. Chief source: in 1961 the UK Atomic Energy Authority extracted 125 g of pure protactinium from uranium fuel elements, and this is the major world stock of this element. World production/tonnes y“‘: n.a.

Abundances Sun (relative to H = 1 x 1012): n.a. Earth’s crust/p.p.m.: traces Seawater/p.p.m.: 2 x 10 “ Oxidation state: V

Specimen: commercially available, under licence

- see Key. 167

Atomic number: 88

CAS:

Relative atomic mass (12C = 12.0000): 226.0254 (Ra-226)

[7440-14-4]

CHEMICAL Description: Radium is a silvery, lustrous, soft, radioactive metal of the alkaline-earth group

It is bright when freshly prepared but darkens on exposure to air. Radium reacts with oxygen and water. Radium salts luminesce. The curie (Ci) is a unit of radioactivity and is defined as that amount of radioactivity which has the same disintegration rate as 1 g of 226Ra, which is 3.7 x 1010 disintegrations per second. Radium was used to treat cancer and for luminous paints, but these uses are now largely superseded. Radii/pm: Ra2+ 152; atomic 223 Electronegativity: 0.89 (Pauling); 0.97 (Allred); n.a. (absolute) Effective nuclear charge: 1.65 (Slater)

Standard reduction potentials £"7V II „ 2+

-2’916

RaO

1,319



Ra2 -Ra Ra

Oxidation states Ra11

[Rn]

RaO, Ra(OH)2, [Ra(OH2)J2+ (aq), Ra2+ salts

Melting point/K: 973

AWf^/kJ mol ': 7.15 AWvap/kJ mol1: 136.8

Boiling point/K: 1413

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

Af//*VkJ mol1

AfG®/kJ mol1

0 159

0 130

S230

Key isotopes Nuclide

Atomic mass

223Ra* 24Ra* 22flRa, 227Ra

Half life (T„2) Decay mode and energy (MeV)

Nuclear Nucl. mag. Uses spin I moment /t

223.018501

11.435 d

a (5.979); y

3/2+?

224.020 186

3.66 d

a (5.789); y

0+

226.025402

1599y

a (4.780); y

0+

227.029 170

42 m

P’ (1.324); y

312+1

228Ra*

228.031064

5.76 y

P~ (0.046); no y

0+

“Ra

230.036990

1.5 h

P' (0.9); y

0+

+0.271 R, T -0.404

* Traces of these isotopes occur naturally Other isotopes of radium have half lives shorter than 5 minutes.

NMR [Not recorded]

•ELECTRON

SHELL

Ground state electron configuration: [Rnj7s2 Term symbol: *S0 Electron affinity (M -> M ) / k) mol"1: n.a. Electron binding energies/eV

Ionization energies/kj mol 1.

2. 3. 4. 5. 6. 7. 8. 9. 10.

M M+ M2* M3t M4+ M5+ M6t M7+ M8+ M9+

—4 —> —> -4 —4 —4 -4 -4 —4 —4

K L, L„ Lm M, Mu Mu, MJV Mv

509. M+ 979. M2* (3300) M3+ (4400) M'1+ (5700) M5+ (7300) M6+ (8600) M7+ (9900) M8+ M9+ (13 500) MIOt (15 100)

•CRYSTAL

Is 2s 2pm 2P3/2 3s 3Pl,2 3P3/2 3d3/2 3d5/2

103 922 19 237 18 484 15 444 4822 4490 3792 3248 3105

Main lines in atomic spectrum

[Wavelength/nm(species)] 364.955 (II) 381.442 (II) 434.064 (ID 468.228 (II) 482.591 (I)

continued in Appendix 2, p257

DATA

Crystal structure (cell dimensions/pm), space group

b.c.c. {a- 515) X-ray diffraction: mass absorption coefficients (/i/p)/cm! g"1: CuKa 304

MoKa 172

Neutron scattering length, fo/1012 cm: 1.00 (226Ra) Thermal neutron capture cross-section, o, /barns: 12.8 (2z6Ra)

• GEOLOGICAL

I

a

A T A

Minerals All uranium minerals contain radium, and there is about 1.5 g of radium in 10 tonnes of the uranium ore, pitchblende. At one time it was separated from this source but this is no longer undertaken. It has been estimated that each square kilometre of soil (to a depth of a 40 cm) contains 1 g of radium. World production: n.a. but probably very little Main mining areas: not really applicable, but see

uranium. Specimen: commercially available, under licence

- see Key.

Abundances Sun (relative to H = 1 x 1012): n.a. Earth’s crust/p.p.m.: 6

x

10"7

Seawater/p.p.m.: 2 x 101' Oxidation state: II

169

Rn

Atomic number: 86

CAS:

Relative atomic mass (12C = 12.0000): 222.0176 (Rn-222)

[10043-92-2]

•:

•CHEMICAL Description: Radon is a colourless, odourless gas produced by radium-226. When radon is

cooled below its freezing point, it phosphoresces brightly. It is little studied, partly because it is a noble gas and is therefore reluctant to form molecules, and partly because its intense radiation would destroy any compound that might form. Radon is sometimes used in hospitals to treat cancer. Radii/pm: n.a. Electronegativity: n.a. (Pauling); 2.06 (Allred); [5.1 eV (absolute) - see Key] Effective nuclear charge: 8.25 (Slater); 16.08 (dementi); 20.84 (Froese-Fischer)

Oxidation states

Covalent bonds

Rn° Rn11

Bond Rn—F

[Rn] s2p4

Rn gas RnF2

•PHYSICAL

r/ pm n.a.

E/ kj mol'1 n.a.

DATA

Melting point/K: 202

AWf^/kJ mol'1: 2.7 (est.)

Boiling point/K: 211.4

AW„p/kJ mol"1: 18.1

Critical temperature/K: 377 Critical pressure/ kPa: 6300

Thermodynamic properties (298.15 K, o.i MPa) State Solid Gas

AfH®/kJ mol"1 0 n.a.

AtGe/kJ mol"1 0 n.a.

S*/J K"' mol n.a. 176.21

C„/J K 1 mol'1 n.a. 20.786

Density/kg m"3: n.a. [solid]; 4400 [liq. at b.p.]; 9.73 [gas, 273 K] Molar volume/cm3: 50.5 [211 K] Thermal conductivity/W m"1 K'1: 0.00364 (est.) [300 K] (g) Coefficient of linear thermal expansion/K'1: n.a. Electrical resistivity/a m: n.a. Mass magnetic susceptibility/kg"1 m3: n.a.

G I C A L Biological role

Levels in humans

None.

Organs: virtually nil Daily dietary intake: nil Total mass of element in average (70 kg) person: virtually nil

Toxicity The high radiotoxicity of radon overrides other toxicity considerations, but chemically it would be inert like the other noble gases.

Hazards Radon is very dangerous because it is an a-emitter, and the maximum permissible concentration in air is 3 x 10"4 Bq cm"3 for an 8 hour day, 40 hour week. Radon is a hazard in uranium mines, and worrying concentrations have been detected inside homes in certain regions.

170

Discovered in 1900 by F.E. Dorn at Halle, Germany.

Radon

[Named after the element radium] French, radon-, German, Radon-, Italian, radon (emanio); Spanish, radon

•NUCLEAR

[ray-don]

A T A

Number of isotopes (including nuclear isomers): 28

Isotope mass range: 200 -> 226

Key isotopes Nuclide

Atomic mass

Half life (T„2) Decay mode and energy (MeV)

Nuclear Nucl. mag. Uses spin 1 moment p

2“Rn

207.989610

24.3 m

a (6.260) 60%; EC (2.9) 40%

0+

OTRn

208.990370

29 m

(5* (3.93) 83%; a 17%; y

5/2-

210Rn

209.989669

2.4 h

a (6.157) 96%; EC (2.368) 4%; y

0+

21‘Rn

210.990576

14.6 h

P* EC (2.89) 74%; a (5.964) 26%; y

1/2-

2l2Rn

211.990697

24 m

a (6.385)

Of

220Rn*

220.011368

55.6 s

a (6.404); y

Of

221 Rn

221.015470

25 m

a (6.148) 22%; p (1.150) 78%; y

7/2+

2Z2Rn*

222.017570

3.8235 d

a (5.590); y

Of

23 m

Ply

Of

223Rn

1.8 h Piy •Traces of these isotopes occur naturally. Other isotopes of radon have half lives shorter than 10 minutes.

“Rn

+0.8388 +0.60

-0.020 T

Of

NMR [Not recorded]

•ELECTRON

SHELL

Ground state electron configuration: [Xe]4f145d106s26p6 = [Rn] Term symbol: 'S„ Electron affinity (M -> M')/kJ mol'1: -41 (est.) Ionization energies/kj mol'':

1. 2. 3. . 4. 5.

M -4 M+ M4 -4 M24 M24 -4 M3+ M34 -» M44 M44 -4 M54

1040 1930 2890 4250 5310

Electron binding energies / eV

K L, Ln

I+n M, M„ Mm Mk

Mv

Is 2s 2Pl/2 2pa/2 3s 3Pl/2 3P3/2 3d3/2 3d5/2

98404 18 049 17337 14 619 4482 4159 3538 3022 2892

Main lines in atomic spectrum

[Wavelength/nm(species)] 434.960 (I) 705.542 a) 726.811 (I) 745.000 (I)

780.982 (1) 809.951 (1) 827.096 (I) 860.007 (I)

continued in Appendix 2, p257

•CRYSTAL

DATA

Crystal structure (cell dimensions/pm), space group

f.c.c. X-ray diffraction: mass absorption coefficients (ii/p)lcm2 g ': CuK„ n.a.

MoKu n.a.

Neutron scattering length, b/10'12 cm: n.a. Thermal neutron capture cross-section, o, / bams: 0.72 (222Rn)

•GEOLOGICAL

DATA

Minerals Radon emanates from thorium and uranium minerals. It collects over samples of radium, “"Ra, in sealed tubes, and 1 g of radium produces 0.0001 cm3 of radon per day. Some spring waters, such as those at Hot Springs, Arkansas, contain dissolved radon gas. Chief source: obtained from 226Ra ampoules

Abundances

Specimen: commercially available, under licence

Sun (relative to H = 1 x 10 ): n.a. Earth’s crust/p.p.m.: traces Atmosphere/p.p.m. (volume): 1 x 1015 Seawater/p.p.m.: c. lx 10'14 Oxidation state: 0

-see Key

171

Atomic number: 75

CAS:

Relative atomic mass (l2C = 12.0000): 186.207

•CHEMICAL

[7440-15-5]

DA

Description: Rhenium is a silvery metal, but is usually obtained as a grey powder. It resists

corrosion but slowly tarnishes in moist air. Rhenium dissolves in HN03 and H2S04. It is used in filaments, thermistors and catalysts. Radii/pm: Re7* 60; Re6+ 61; Re4+ 72; atomic 137; covalent 128 Electronegativity: 1.9 (Pauling); 1.46 (Allred); 4.02 eV (absolute) Effective nuclear charge: 3.60 (Slater); 10.12 (Clementi); 14.62 (Froese-Fischer)

Standard reduction potentials £~7V VII

VI

IV

III

0.34

_

acid

0.768

0.22

0.63

0.10

Re-Re

[Re04] -Re03-Re02 0.51

0.12

[ReCl6]

2-

0.51

,

-0.808

base

_ -0.890

-0.446

-1.25

0.333

[Re04] -Re03-Re02.2H20- Re203-Re -0.594

-0.564 -0.604

Oxidation states Re"111 Re"1 Re0 Re1 Re11 Re1"

d10 d8 d7 d6 d5 d4

[RetCOh]3" [Re(CO)5r [Re2(CO)10] [ReCl(COy,K5[Re(CN)6] ReF2, ReCl2 etc. ReXb.xLLO, Re3Cl9, Re3Br9, Re3I9, [Re2Cl8]2", [ReCCNJy]4", complexes

Relv

d3

Rev

d2

Re"1

d1

Revn

d°[f14]

Re02, ReF4, ReCl4 etc., complexes Re205, ReF5, ReCl5, ReBr3, ReF30, complexes Re03, ReF6, ReCl6, [ReFs]2", ReCl40, complexes Rez07, ReF7, ReF03, ReF50, [Re04]“ (aq), [ReH9]2“, complexes

•PHYSICAL AWfusira/kJ mol ‘: 33.1 AWvap/kJ mol1: 707.1

Melting point/K: 3453 Boiling point /K: 5900

Thermodynamic properties (298.15 K, o.l MPa) State Solid Gas

Af//®/kJ mol1 0 769.9

AfG®/kJ mol1 0 724.6

S M8* -> M9* —> M10*

720 1744 2997 (4400) (6500) (8200) (10 100) (12 200) (14 200) (22 000)

Electron binding energies/eV

K L, Lu Lni M, M„ Mm MIV Mv

Is 2s 2Pl/2 2p3/2 3s 3Pi/2 3p3/2 3d3/2 3d5/2

Main lines in atomic spectrum

[Wavelength/nmfspecies)] 343.489 (I) (AA) 350.252 (I) 352.802 (I) 365.799 (I) 369.236 (I) 370.091 (I)

23 220 3412 3146 3004 628.1 521.3 496.5 311.9 307.2

continued in Appendix 2, p257

•CRYSTAL Crystal structure (cell dimensions/pm), space group

f.c.c. (a = 380.36), Fm3m X-ray diffraction: mass absorption coefficients (ft/p)/cm2 g'1: CuK„ 194 MoKa 22.6 Neutron scattering length, £>/10"12 cm: 0.588 Thermal neutron capture cross-section, M")/kJ mol-1: 46.9 Ionization energies/kj mol ::

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M4 M24 M34 M4+ M5+ M6+ M74 M84 M94

—> M4 M24 —> M34 —> M44 —> M54 -> M64 -> M74 —> M84 —> M94 -» M'04

403. 2632 3900 5080 6850 8140 9570 13100 14800 26 740

Electron binding energies /eV

K L, Lit I+u M, M„ MIU Miv My

Is 2s 2Pl/2 2P3/2 3s 3Pl/2 3P3/2 3d3/2 3d5/2

15 200 2065 1864 1804 326.7 248.7 239.1 113.0 112

Main lines in atomic spectrum

[Wavelength /nm (species) ] 214.383 (II) 247.220 (II) 424.440 (II)

477.595 (II) 780.027 (I) (AA)

794.760 (I)

continued in Appendix 2. p257

•CRYSTAL Crystal structure (cell dimensions/pm), space group

b.c.c. (a = 562), Im3m X-ray diffraction: mass absorption coefficients (p/p)lcm2 g_1: CuKa 117 MoK„ 90.0 Neutron scattering length, bl 10“12 crh: 0.709 Thermal neutron capture cross-section, aa/barns: 0.38

•GEOLOGICAL Minerals No minerals as such are known, but rubidium is present in significant amounts in lepidolite (see lithium), pollucite (see caesium) and carnallite (see potassium).

World production/tonnes y~‘: n.a.

Reserves/tonnes: n.a. Specimen: available as ingots in sealed ampoules.

Danger!

Abundances Sun (relative to H = 1

x

1012): 400

Earth’s crust/p.p.m.: 90 Seawater/p.p.m.: 0.12 Residence time/years: 800 000 Classification: accumulating Oxidation state: I

177

Atomic number: 44 Relative atomic mass (,2C= 12.0000): 101.07

•CHEMICAL

CAS: [7440-18-81

DATA

Discovery: Ruthenium was discovered in 1808 by J.A. Sniadecki at the University of Vilno,

Poland. Rediscovered in 1828 by G.W. Osann at the University of Tartu, Russia. Description: Ruthenium is a lustrous, silvery metal of the so-called platinum group. It is unaffected by air, water and acids, but dissolves in molten alkalis. Ruthenium is used to harden platinum and palladium metals, and as a catalyst. Radii/pm: Ru5+ 54; Ru4* 65; Ru3+ 77; atomic 134; covalent 124 Electronegativity: 2.2 (Pauling); 1.42 (Allred); 4.5 eV (absolute) Effective nuclear charge: 3.75 (Slater); 7.45 (Clementi); 10.57 (Froese-Fischer)

Standard reduction potentials F7 V VIII

VII

III

VI

0.86

II

D>Jt249 Ru2t^Ru

Oxidation states Ru" Ru° Ru1

d10 d8 d7

Ru"

d6

rare [Ru(CO)4]2~ rare [Ru(CO)5] some complexes, e.g. [Ru(CO)2(n-C5H5)]2 [Ru(OH2)6]2+ (aq), RuC12, RuBr2, RuI2, [Ru(CN)6]2 , complexes Ru203, [Ru(OH2)6]3+ (aq), RuF3, RuC13 etc., [RuCl6]3'

Ru111 d5

Ru" Ruv Ru" Ru"1 Ru""

d4 d3 d2 d1 d° [Kr]

Ru02, RuF4, [RuC16]2' RuF5, [RuF6]' Ru03, [Ru04]2' (aq), RuF, [Ru04]' (aq) Ru04

AWfusion/kj mol ': 23.7 AW,ap/kJ mol'1: 567.8

Melting point / K: 2583 Boiling point / K: 4173

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

Af/jP/kl mol'1 0 642.7

AfG®/kJ mol'1 0 595.8

Density/kg m 3: 12 370 [293 K]; 10 900 [liquid at m.p.]

SV J K'1 mol'1

28.53 186.507

Cp/J K'1 mol1 24.06 21.522

Young’s modulus/GPa: 432

Molar volume/cm3: 8.14

Rigidity modulus/GPa: 173

Thermal conductivity/W m 1 K'1: 117 [300 K]

Bulk modulus/GPa: 286

Coefficient of linear thermal expansion/K'1: 9.1

x

10"6

Poisson’s ratio/GPa: 0.25

Electrical resistivity In m: 7.6 x 10"8 [273 K[ Mass magnetic susceptibility/kg'1 m3: +5.37 x 10~9 (s)

m

•BIOLOGICAL

DATA

Biological role

Levels in humans

None.

Organs: n.a. but very low Daily dietary intake: n.a. Total mass of element in average (70 kg) person: n.a.

Toxicity Toxic intake: most ruthenium compounds

are poisonous. Lethal intake: LD50 (Ru02, oral, rat) = 4580 mg kg"1

Hazards Ingested ruthenium is retained in the bones for a long time. The volatile oxide, RuO,, is highly toxic by inhalation. 178



Discovery: see Chemical Data section.





.



Ruthenium

[Latin, Ruthenia = Russia! French, ruthenium; German, Ruthenium; Italian, rutenio; Spanish, rutenio

1 • N U CLEAR

■■

[roo-thee-ni-uhm)

DATA

Number of isotopes (including nuclear isomers): 20

Isotope mass range: 92 -> 110

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin I

9cRu

95.907 599

5.52

0+

3BRu

97.905287

1.88

0+

ssRu

98.905 939

12.7

5/2+

99.904 219

12.6

0+

.00Ru 101Ru

100.905 582

17.0

5/2+

l02Ru

101.904348

31.6

0+

103.905 424 18.7 ,01Ru A table of radioactive isotopes is given in Appendix

NMR

-0.718 9

NMR

0+

NMR [Reference: RuOJ

"Ru 1.95x10^ 0.83 -1.2343x 107 +0.079x 10^28 3.389

Receptivity (13C = 1.00) Magnetogyric ratio /rad T's-1 Nuclear quadrupole moment/m2 Frequency (’H = 100 Hz; 2.3488T)/MHz

SHELL

-6.413

l p248.

Relative sensitivity (‘H = 1.00)

•ELECTRON

Nuclear magnetic Uses moment /1

10,Ru 1.41 xl0“3 1.56 -1.3834xl07 +0.457x 10"28 4.941

DATA

Ground state electron configuration: [Kr]4d75s' Term symbol: 5F5 Electron affinity (M -> M')/kJ moF': 101 Electron binding energies/eV

Ionization energies/kj mol

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

711 M —> M' 1617 M* —> M2* 2747 M2* -> M3+ (4500) M3* M4+ (6100) M4t -> M5+ (7800) M5+ -4 M6+ (9600) Mr” M7t M7* -> M8* (11 500) M8‘ —> M9+ (18 700) Ms+ —> M10t (20 900)

K L,

Is 2s

u

2pic

bn M, M„ Mm M,v Mv

2P3/2

Main lines in atomic spectrum

|Wavelength/nm(species)] 349.894 (I) 372.693 (I) 372.803 (I) (AA) 379.890(1) 379.935 Q) 419.990 (I)

22117 3224 2967 2838 586.1 483.7 461.5 284.2 280.0

3s 3pt/2 3p3/2

3d3/2 3d5/2

continued in Appendix 2. p257

•CRYSTAL Crystal structure (cell dimensions/pm), space group

h.c.p. (a = 270.58, c = 428.11), P63/mmc X-ray diffraction: mass absorption coefficients (p/p)/cm2 g"1: CuKa 183 MoKa 21.1 Neutron scattering length, bl 10"12 cm: 0.721 Thermal neutron capture cross-section, M )/kJ mol1: < 50 Ionization energies/kj mol':

1. 2. 3. 4. 5.

M M* M2+ M3+ M4+

-> -4 -» -> -+

M* M2t M3+ M4+ M5+

543.3 1068 2260 3990 6046

Electron binding energies / eV

K L, L„ Lin Mi

Mh

M,„ Hv Mv

Is 2s 2Pl/2 2p3t2 3s 3pi/2 3P3/2

46 834 7737 7312 6716 1723 1541 1419.8 1110.9 1083.4

3d3/2

3d5/2

Main lines in atomic spectrum

[Wavelength/nm (species)] 356.827 (II) 359.260 (II) 363.429 (II) 373.912 (II) 388.529 (II) 429.674 (I) (AA)

continued in Appendix 2, p257

•CRYSTAL

DATA

Crystal structure (cell dimensions/pm), space group

«-Sm rhombohedral (a = 899.6, a = 23° 13'), R3m /1-Sm cubic (a = 407), Im3m T(a->)3) = 1190 K high pressure form: h.c.p. (a = 361.8, c = 1 166), P63/mmc X-ray diffraction: mass absorption coefficients (/i/p) / cm2 g 1: CuKa 397 MoKa 58.6 Neutron scattering length, bl 10-12 cm: 0.080 Thermal neutron capture cross-section, cra/barns:5922 •GEOLOGICAL

Minerals Mineral Monazite*

Formula Density Hardness Crystal appearance (Ce, La, Nd, Th, etc)PO„ 5.20 5-5.5 mon., waxy/vit. yellow-brown

‘Although not a major constituent, samarium is present in extractable amounts. Chief ore: monazite World production/tonnes y ': c. 700 Main mining areas: USA, Brazil, India, Sri Lanka,

Australia Reserves/tonnes: c. 2 x 106 Specimen: available as chips or ingots. Safe.

Abundances Sun (relative to H = 1 x 1012): 5.2 Earth’s crust/p.p.m.: 7.9 Seawater/p.p.m.:

Atlantic surface: 4.0 x 10 7 Atlantic deep: 6.4 x 10 ' Pacific surface: 4.0 x 10 7 Pacific deep: 10 x 10'7 Residence time /years: 200 Classification: recycled Oxidation state: III

I 183

Atomic number: 21 Relative atomic mass (12C= 12.0000): 44.955910

CAS: [7440-20-2]

•CHEMICAL Description: Scandium is a soft, silvery-white metal which tarnishes in air and burns easily,

once ignited. It reacts with water to form hydrogen gas. There are only a few, rather specialised, uses for scandium such as in mercury vapour lights for high intensity lighting when a sunlight effect is required. Radii/pm: Sc3* 83; atomic 161; covalent 144 Electronegativity: 1.36 (Pauling); 1.20 (Allred); 3.34 eV (absolute) Effective nuclear charge: 3.00 (Slater); 4.63 (Clementi); 6.06 (Froese-Fischer)

Standard reduction potentials E^IV

Oxidation states Sc" Scm

d1 [Ar]

CsScCl, Sc203, ScO.OH, ‘Sc(OH)3’, [Sc(H20)7]3+ [Sc(OH)6]3-, ScF3, ScCl3, etc., [ScFu]3-, complexes ScH2 is probably ScmFF with complex bonding

•PHYSICAL

DATA

Melting point/K: 1814

AHf^/kJ mol ': 15.9 AWvap/kJ mol-1: 304.8

Boiling point/K: 3104

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

z\r//*/kJ

moT1

0 377.8

AfGe/kJ

0

336.03

moT1

S°lJ K1 moT1

34.64 174.79

C„/J K 1 mol1 25.52 22.09

Density/kg nr3: 2989 [273 K]

Young’s modulus/GPa: 74.4

Molar volume/cm3: 15.04

Rigidity modulus/GPa: 29.1

Thermal conductivity/W m_1 K_1: 15.8 [300 K]

Bulk modulus / GPa: 56.6

Coefficient of linear thermal expansion/K-1:10.0 x 10 ‘*

Poisson’s ratio/GPa: 0.279

Electrical resistivity IQ m: 61.0 x 10-8 [295 K] Mass magnetic susceptibility/kg 1 m3: +8.8 x 10 8 (s)

•BIOLOGICAL Biological role

Levels in humans

None.

Blood/mg dm"3: c. 0.008 Bone/p.p.m.: C. 0.001 Liver/p.p.m.: 0.0004 - 0.0014 Muscle/p.p.m.: n.a. Daily dietary intake: C. 0.00005 mg Total mass of element in average (70 kg) person: C. 0.2 mg

Toxicity Toxic intake: n.a. Lethal intake: LD50 (chloride, oral, mouse) 4000 mg kg-1

Hazards Scandium is mildly toxic by ingestion, and scandium salts are suspected of being carcinogenic.

184

Discovered in 1879 by L.F. Nilson at Uppsala, Sweden.

Scandium

(Latin, Scandia = Scandinavia] French, scandium-, German, Scandium-, Italian, scandio; Spanish, escandio

(skan-dium)

•NUCLEAR Number of isotopes (including nuclear isomers): 15

Isotope mass range: 40 -»51

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin I

Nuclear magnetic Uses moment p

15Sc

44.955 910

100

7/2-

+4.756 483

NMR

A table of radioactive isotopes is given in Appendix 1, on p248.

NMR [Reference: Sc(C104)3 (aq)]

45Sc 0.30 1710 6.4982x 107 -0.220 x 10'28 24.290

Relative sensitivity (‘H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T 1 s4 Nuclear quadrupole moment/m2 Frequency (‘H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

DAT

Ground state electron configuration: [Ar]3d'4s2 Term symbol: 2D3/2 Electron affinity (M -> M')/kJ mol'1: 18.1 Electron binding energies /eV

Ionization energies/kj mol

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M+ M2+ M3* M4+ M5t M6* M74 M8t M9+

-+ M* +> M2t -> M34 -» M4+ -+ M5+ -+ M6+ ->■ M7+ -+ M8+ -+ M9* M10+

631 1235 2389 7089 8844 10 720 13 320 15 310 17369 21740

•CRYSTAL

K L, Ln Lm M, Mn Miir

Main lines in atomic spectrum

[Wavelength/nm(species)]

4492 498.0 403.6 398.7 51.1 28.3 28.3

Is 2s 2Pl/2 2p3/2 3s 3pi/2 3P3/2

361.384 (I)

363.075 390.749 391.181 402.040 402.369

(II) (I) (I) (AA) (I) (I)

DATA

Crystal structure (cell dimensions/pm), space group

a-Sc h.c.p. (a = 330.90, c = 527.3), P63/mmc /3-Sc cubic, Im3m T{a ->p)= 1223 K X-ray diffraction: mass absorption coefficients (p/p)/cm2 g"1: CuKa 184 MoK„ 21.1 Neutron scattering length, £>/10~12 cm: 1.23 Thermal neutron capture cross-section, M")/kJ mol"1: n.a. Ionization energies/kj mol"1:

1. M

M*

730 (est.)

•CRYSTAL

Electron binding energies/eV

Main lines in atomic spectrum

n.a.

[Wavelength/nm(species)] n.a.

DATA

Crystal structure (cell dimensions/pm), space group

n.a. X-ray diffraction: mass absorption coefficients (p/p)/cm2 g ’: CuKa n.a. MoK„ n.a. Neutron scattering length, h/10"12 cm: n.a. Thermal neutron capture cross-section, (7,/barns: n.a.

•GEOLOGICAL Minerals Not found on Earth.

Chief source: several atoms of seaborgium have

Abundances

been made from 249Cf by bombarding it with 180 nuclei: 249Cf + 180 -> 263Sg + 4n. This was done with an 88-inch-diameter cyclotron which produces about a billion atoms per hour of which only one is element 106. Bombarding 248Cm with 22Ne produced the heavier isotopes, 265Sg and 266Sg, which have longer-than-expected half-lives of 2.8 sec and 27.3 sec respectively.

Sun (relative to H = 1

x

1012): n.a.

Earth’s crust/p.p.m.: nil Seawater/p.p.m.: nil

Specimen: not available commercially.

187

Description: Selenium is obtained in either a silvery metallic form (grey Se) or a red amorphous powder, which is less stable. Selenium burns in air, is unaffected by water, but dissolves in concentrated HN03 and alkalis. It is used in photoelectric cells, photocopiers, solar cells and semiconductors. Radii/pm: Se4+ 69; Se2" 191; atomic 215; covalent 117; van der Waals 200 Electronegativity: 2.55 (Pauling); 2.48 (Allred); 5.89 eV (absolute) Effective nuclear charge: 6.95 (Slater); 8.29 (Clementi); 9.96 (Froese-Fischer)

Standard reduction potentials E*IV VI

IV 1.1

Se042 -FI2Se03-Se-H2Se

base

Se04‘-Se032 -Se-Se2

Oxidation states [Kr] s2p4,

Se1 Se11 Sew

s2p3 s2p2 s2

Sevl

d10

-II -0.11

acid

0.03

Se"11 Se04

0 0.74 -0.36

-0.67

,

Covalent bonds

H2Se Se cluster cations, e.g. Se42+, Sea2+ Se2Cl2, Se2Br2 ? Se02, H2Se03, [Se03]2" (aq), SeF20, SeCl20, SeBr20, SeF4, SeCl4, SeBr4, [SeBr6]2" Se03?, H2Se04, [Se04]2" (aq), Se02F2, Se02Cl2, SeF6

Bond

r/ pm

Se—H Se—C Se—O Se—F Se—Cl Se—Se (Se8)

E/ kj mol

146 198 161 170 220 232

305 245 343 285 245 330

Melting point/K: 490

AW^/kJ mol'1: 5.1

Boiling point/K: 958.1

AWyap/kj mol"1: 26.32

Critical temperature/K: 1766 Critical pressure/kPa: 27200

Thermodynamic properties State Solid (a) Gas

(298.15 K, o.l MPa)

AfbP/kJ mol-1

AfG®/kJ mol"1

S®/J K"1 mol"1

C„/J K"1 mol"1

0 187.03

42.442 176.72

25.363 20.820

0 227.07

Density/kg m"3: 4790 (grey) [293 K]; 3987 [liquid at m.p.]

Young’s modulus/GPa: 58

Molar volume /cm3: 16.48

Rigidity modulus/GPa: n.a.

Thermal conductivity/W m"1 K'1: 2.04 [300 K] Coefficient of linear thermal expansion/K"1:36.9 x 10 6 Electrical resistivity/£2 m: 0.01 [293 K] Mass magnetic susceptibility/kg"1 m3: -4.0 x 10"9 (s)

Bulk modulus/GPa: n.a. Poisson’s ratio/GPa: 0.447

•BIOLOGICAL Biological role

Levels in humans

Essential to some species, including humans, although only in tiny amounts. Selenium acts to stimulate the metabolism.

Blood/mg dm 3:0.171 Bone/p.p.m.: 1-9 Liver/p.p.m.: 0.35 - 2.4 Muscle/p.p.m.: 0.42 - 1.9 Daily dietary intake: 0.006 - 0.2 mg

Toxicity

Total mass of element

Toxic intake: human, Se metal = c. 10 - 35 mg

in average 170 kgl person:

Lethal intake: LD50 (Se metal, oral, rat) =

possible, 10-65 mg)

6700 mg kg"1. A dose of 5 mg per day can be lethal for many humans. LD50 (H2Se03, intravenous, mouse) = 11 mg kg"1.

Hazards Selenium compounds are toxic by inhalation and intravenous routes. They are also considered to be experimental carcinogens, and teratogens.

188

C. 15 mg (wide range

Discovered in 1817 by J.J. Berzelius at Stockholm, Sweden. [Greek, selene = moon]

Selenium

French, selenium; German, Selen; Italian, selenio; Spanish, selenio

[sel-een-iuhm)

•NUCLEAR Number of isotopes (including nuclear isomers): 26

Isotope mass range: 69 -> 89

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

74Se

73.922474 6

0.9

Of

76Se

75.919212 0

9.0

Of

^Se

76.919912 5

7.6

1/2-

78Se

77.9173076

23.6

Of

E

“Se

79.916 519 6

49.7

Of

E

Nuclear spin I

Nuclear magnetic Uses moment p E E t0.535 06

E, NMR

9.2 81.916697 8 Of 82Se A table of radioactive isotopes is given in Appendix 1, on p249 .

NMR [Reference: Se(CH3)2] Relative sensitivity ('H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T's"1 Nuclear quadrupole moment/nr Frequency ('H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

E

77Se 6.93 x 10 3 2.98 5.1018 x 107 19.092

DATA

Ground state electron configuration: [Arl3d!04s24p4 Term symbol: 4P2 Electron affinity (M -> M')/kJ mol1: 195.0 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Main lines in atomic spectrum

Electron binding energies/eV

Ionization energies/kj mol 1:

940. M M+ 2044 M7 —> M2+ 2974 M27 -> M3+ 4144 M3+ —> MJ+ 6590 M47 —> M57 7883 M57 -> M6+ 14990 M6t M77 M87 (19 500) M7+ m3+ (23 300) M8* M9+ -> M'“7 (27 200)

K L, Ln Lin M, M„ Mm M|V Mv

Is 2s ZPll2 2p3/2 3s 3pi/2 3P3/2 3d3/2 3d5/2

[Wavelength/nm(species)l 196.026 (I) (AA) 241.350 (I) 1032.726 (I) 1038.636 (I) 2144.256 (I)

12 658 1652.0 1474.3 1433.9 229.6 166.5 160.7 55.5 54.6

•CRYSTAL Crystal structure (cell dimensions/pm), space group

grey hexagonal (a = 436.56, c= 495.90), P3i21, metallic form «-Se monoclinic {a = 906.4, b= 907.2; c= 115.6, p = 90° 52'), P2,/a, Se8 P-Se monoclinic (a = 1285, b= 807, c= 931, p = 93° 8'), P2!/a, Se„ a'-Se cubic (a = 297.0), Pm3m p'-Se cubic (a = 604), Fd3m X-ray diffraction: mass absorption coefficients cm2 g_1: CuK,( 91.4 MoK„ 74.7 Neutron scattering length, b/10 12 cm: 0.797 Thermal neutron capture cross-section, M")/kJ mol ': 125.7 Ionization energies/k] mol ':

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M* M2+ M3+ M4+ M5+ M6+ M7+ M8* M9+

-> -* -4 -» -* -» -4

-» -» —>

M* M2+ M3" M4+ M5+ M6+ M7* M8+ M9+ M'0+

Electron binding energies/eV

731.0 2073 3361 (5000) (6700) (8600) (11200) (13 400) (15 600) (18 000)

K L, Ln 1« M, M„ M,„ M„ Mv

25 514 3806 3524 3351 719.0 603.8 573.0 374.0 368.0

Is 2s 2pi/2 2p3/2 3s 3Pl/2 3P3/2 3d3/2 3d5/2

Main lines in atomic spectrum

[Wavelength/nm(species)j 328.068 0) (AA) 338.289 d) 520.908 (I) 546.550 (I) 827.352 (I)

continued in Appendix 2, p257

•CRYSTAL Crystal structure (cell dimensions/pm), space group

f.c.c. (a = 408.626), Fm3m X-ray diffraction: mass absorption coefficients (/j/p)/cm2 g 1: CuKa 218 MoKa 25.8 Neutron scattering length, b/10“12 cm: 0.597 Thermal neutron capture cross-section, 31

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin l

z3Na 22.989 767 100 3/2+ A table of radioactive isotopes is given in Appendix 1, on p249.

NMR (Reference: NaCl (aq)]

+2.217520

NMR

23Na 0.0925 525 7.0761 x 107 0.1089 x 10'28 26.451

Relative sensitivity ('H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T's-1 Nuclear quadrupole moment/m2 Frequency (‘H = 100 Hz; 2.3488T)/MHz

•ELECTRON

Nuclear magnetic Uses moment it

SHELL

Ground state electron configuration: (Ne]3s‘ Term symbol: 2Si,2 Electron affinity (M -> M")/kJ mol'1: 52.9 Ionization energies/k] mol :

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M* M2’ M3* M5* M6+ M7+ M8* M9*

-+ -+ -+ -+ -+ -» -> -+ > ++

M* M2+ M3* M4+ M5+ M6+ M7+ M8" M9* M10+

495.8 4562.4 6912 9543 13 353 16 610 20114 25 490 28 933 141 360

Electron binding energies / eV

K

L, Ln Lm

Is 2s 2pi/2 2p3/2

Main lines in atomic spectrum

(Wavelength/nm(species)] 313.548 (II) 588.995 (I) (AA) 589.592 (I) 818.326 (I) 819.482 (I)

1070.8 63.5 30.4 30.5

•CRYSTAL Crystal structure (cell dimensions/pm), space group a-Na hexagonal (a = 376.7, c= 615.4), P63/mmc /1-Nab.c.c. (a = 429.06), Im3m 7Tb.c.c. -r hexagonal) = 5 K X-ray diffraction: mass absorption coefficients [fi/p)tcm2 g"1: CuKa 30.1 MoKa 3.21 Neutron scattering length, b/10“12 cm: 0.358 Thermal neutron capture cross-section, cra/barns: 0.530

• GEOLOGICAL

DATA

Minerals Sodium occurs in many minerals but these are not mined as a source of sodium compounds. Mineral Formula Density Hardness Halite (rock salt) NaCl 2.168 2 Trona Na3(C03)(HC0J.2H20 2.14 2.5-3 Chief ores: halite, trona World production/tonnes y'1: c. 200 000 (sodium

metal); 168 x 106 (salt); 29 x 106 (sodium carbonate) Main mining areas: halite in Germany, Poland, USA, UK; trona in Kenya, USA Reserves/tonnes: almost unlimited

Crystal appearance cub., vit. usually colourless mon., vit. colourless

Abundances Sun (relative to H = 1 x 1012): 1.91 x 10s Earth’s crust/p.p.m.: 23 000 Seawater/p. p.m.: 10 500 Residence time/years: 1 x 108 Classification: accumulating Oxidation state: I

Specimen: available as ingots or lumps, in sealed

ampoules under nitrogen, or spheres and sticks stored under mineral oil. Warning!

195

Atomic number: 38 Relative atomic mass (i2C = 12.0000): 87.62

CAS: [7440-24-6]

•CHEMICAL Discovery: Strontium was recognized as an element in 1790 by A. Crawford at

Edinburgh, Scotland. Isolated in 1808 by Sir Humphry Davy at London, England. Description: Strontium is a silvery-white, relatively soft metal that is obtained by heating strontium oxide (SrO) with aluminium metal. The bulk metal is protected by an oxide film, but it will burn in air if ignited, and is attacked by water. Strontium is used in special glass for televisions and VDUs, and the red colour of fireworks and flares is produced by strontium salts. Radii/pm: Sr2* 127; atomic 215 (a-form); covalent 192 Electronegativity: 0.95 (Pauling); 0.99 (Allred); 2.0 eV (absolute) Effective nuclear charge: 2.85 (Slater); 6.07 (Clementi); 8.09 (Froese-Fischer)

Standard reduction potentials E /V

o

II

-II

-1.085

Sr

-2.89



Sr-

0.718

SrH2*

-2.047

SrO (hyd.) -

-0.665

Also 2.333

,,

Sr02*-Sr2 1.492

Sr02-SrO (hyd.) * see oxidation states

Oxidation states Sr11

[Kr]

SrO, Sr02 (peroxide), Sr(OH)2, [Sr(OH2)J2+ (aq), Sr2* salts, SrF2, SrCl2 etc., SrC03, some complexes. SrH2 is Sr^H'

•PHYSICAL Melting point/K: 1042

mol ': 9.16 AH,„/kJ mol'1: 138.91

Boiling point/K: 1657

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

Af//6/kJ mol'1 0 164.4

AfG*7kJ mol'1 0 130.9

SVJ K'1 mol'1 52.3 164.62

Cp/I K 1 mol'1 26.4 20.786

Density/kg m'3: 2540 [293 K]; 2375 [liquid at m.p.]

Young’s modulus/GPa: 15.7

Molar volume/cm3: 34.50

Rigidity modulus/GPa: 6.03

Thermal conductivity/W m'1 K'1: 35.3 [300 K]

Bulk modulus/GPa: 12.0

Coefficient of linear thermal expansion /K'1:23 x 10 r’

Poisson’s ratio/GPa: 0.28

Electrical resistivity In m: 23.0

10'8 [293 K] Mass magnetic susceptibility/kg'1 m3: +1.32 x 10~® (s) x

•BIOLOGICAL Biological role

Levels in humans

None. Toxic intake: not regarded as toxic

Blood/mg dm"3:0.031 Bone/p.p.m.: 36- 140 Liver/p.p.m.: 0.05 - 0.36 Muscle/p.p.m.: 0.12 - 0.35

Lethal intake: LD50 (chloride, oral, rat) = 2250 mg kg'1

Total mass of element

Toxicity

Hazards Strontium resembles calcium in metabolism and behaviour and is absorbed by the body and stored in the skeleton. This also happens with radioactive 90Sr which was produced by above-ground nuclear explosions in the 1950s and is widely disseminated in the environment.

196

Daily dietary intake:

0.8 — 5 mg

in average 170 kgl person:

320 mg

Discovery: see Chemical Data section.

Strontium

(Named after Strontian, Scotland] French, strontium-, German, Strontium-, Italian, stronzio-, Spanish, estroncio

[stron-tee-uhm]

•NUCLEAR Isotope mass range: 79 -»98

Number of isotopes (including nuclear isomers): 23

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

“Sr

83.913 430

0.56

Of

"6Sr

85.909 267

9.86

Of

^Sr

86.908884

7.00

912+

Nuclear magnetic Uses moment p

Nuclear spin /

E -1.09283

E, NMR

87.905 618 82.58 Or “Sr A table of radioactive isotopes is given in Appendix 1, on p249.

NMR [Reference: Sr2+ (aq)] Relative sensitivity (1H = 1.00)

2.69 xlO"3 1.07 -1.1593 x 107 0.335 x 10“28 4.333

Receptivity (13C= 1.00) Magnetogyric ratio/rad T's"1 Nuclear quadrupole moment/m2 Frequency (*H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

DATA

Ground state electron configuration: [Kr]5s2 Term symbol: 'S0 Electron affinity (M -» M~)/kJ mol"1: -146 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M* M2+ M3+ M4+ M5* M6t M7+ M8’ M9+

-> M* —> M2t —> M3+ —> M"*M5+ —> M6* —> M7t M8* -> M9* —> M10*

Main lines in atomic spectrum

Electron binding energies/eV

Ionization energies/kj mol 1:

549.5 1064.2 4210 5500 6910 8760

K L, L., Lin M, Mu Mu, M|V Mv

10200

11800 15 600 17100

Is 2s 2Pl/2 2P3/2 3s 3Pl/2 8p3/2 3d3/2 3d5/2

[Wavelength/nm(species)l 407.771 (II) 421.552 (II) 460.733 (I) (AA) 496.226 (I) 548.084 (I) 640.847 (I)

16105 2216 2007 1940 358.7 280.3 270.0 136.0 134.2

continued in Appendix 2, p257

•CRYSTAL Crystal structure (cell dimensions/pm), space group

a-Sr f.c.c. (a = 608.49), Fm3m /3-Sr h.c.p. (a = 432, c = 706), P63/mmc ^Sr b.c.c. (a = 485), Im3m 71 or -> p) = 506 K; 7T/3 -4 yl = 813 K X-ray diffraction: mass absorption coefficients (p/p)/cm2 g Neutron scattering length, b/10~'2 cm: 0.702 Thermal neutron capture cross-section, a,!barns: 1.28

•GEOLOGICAL

CuK„ 125 MoKa 95.0

DATA

Minerals Mineral Celestite* Strontianite

Formula SrS04 SrC03

Density 3.97 3.76

Hardness / -3.5 3.5

Crystal appearance orth., vit./colourless-pale blue orth., vit./resinous colourless

*Also known as celestine. Chief ores: celestite, strontianite World production/tonnes y1: 137 000 (strontium

ores) Main mining areas: UK, Tunisia, Russia, Germany, Mexico, USA Reserves/tonnes: n.a. Specimen: available as granules and pieces.

Warning!

Abundances Sun (relative to H = 1 x 1012): 790 Earth’s crust/p.p.m.: 370 Seawater/p. p.m.:

Atlantic surface: 7.6 Atlantic deep: 7.7 Pacific surface: 7.6 Pacific deep: 7.7 Residence time/years: 4 x 106 Classification: recycled Oxidation state: II

197

Atomic number: 16 Relative atomic mass (12C = 12.0000): 32.066

CAS: [7704-34-9]

CHEMICAL Description: There are several forms of sulfur, of which the yellow orthorhombic (S8) is the

most common. Sulfur is stable to air and water, but bums if heated. It is attacked by oxidising acids. It is a key industrial chemical and is the starting point for sulfuric acid. Radii/pm: S6‘ 29; S4‘ 37; S2' 184; atomic 104; covalent 104; van der Waals 185 Electronegativity: 2.58 (Pauling); 2.44 (Allred); 6.22 eV (absolute) Effective nuclear charge: 5.45 (Slater); 5.48 (Clementi); 6.04 (Froese-Fischer)

Standard reduction potentials ZT7V VI

V

IV

0.16

acid

,

-0.07

ip

III

-II

0.40 0.57

-0.07

0.87

9

S042 -S2062 -H2S03- HS204 -S2032

0.60

0.14

-0.74

-0.45

-S-H2S

0.50

.

also

9-

2.01

S2082 -S042

-0.94

-0.66

-0.58

s2o32--

SO,

‘average oxidation state

Oxidation states

S-H S'1

s° s1 su sm SIV

sv SW

[Ar] szp5 szp4 s2p3 szp2 s2p‘ s2 s1 [Ne]

Covalent bonds

H2S, S2~, polysulfides S,,2* H2S2, etc., polysulfides S,,2S6, S8, etc., polysulfides S„^ S20?, S2F2, S2C12 sf2, SC12 Na2S204 S02, S032“ (aq), SF4, SC14, SOCl; Na2S206, S2F10 S03, H,S04, S042~ (aq), etc., SF6 HS03F, S02C12

Bond S-H S-C S=C S-0

r / pm 134 182 160 150 143 156 207 205

s=o S-F S-Cl S-S

E/kJm 363 272 573 265 532 284 255 226

•PHYSICAL Melting point/K: 386.0 (a); 392.2 (0); 380.0 M

AWfusi,,,/kj mol': 1.23 AW,ap/kJ mol1: 9.62

Boiling point / K: 717.824 Critical temperature/K: 1314 Critical pressure/kPa: 20700

Thermodynamic properties (298 .15 K, 0.1 MPa) State Solid (a) Solid (|3) Gas

Af//*/kJ mol1 0 0.33 278.805

AfG®/kJ mol 1 0 n.a. 238.250

Se/J K1 mol1 31.80 n.a. 167.821

Cp/J K1 mol1 22.64 n.a. 23.673

Density/kg nr3: 2070 (a), 1957 (p) [293 K]; 1819 [liquid at 393 K] Molar volume/cm3: 15.49 Thermal conductivity/W nr1 K 1: 0.269 (a) [300 K] Coefficient of linear thermal expansion/K ': 74.33 x 106 Electrical resistivity In m: 2 x 1015 [293 K] Mass magnetic susceptibility/kg 1 m3: -6.09 x 10“9 (a); -5.83 x 10 11 (/j)

•BIOLOGICAL

DATA

Biological role

Levels in humans

Essential to all living things; part of the amino acids methionine and cysteine.

Blood/mg

Toxicity

dmf3:1800 500- 2400 Liver/p.p.m.: 7000- 12 000 Muscle/p.p.m.: 5000 - 11 000 Daily dietary intake: 850 - 930 mg Bone /p.p.m.:

Elemental sulfur is not very toxic, but simple derivatives (S02, H2S, etc.) are.

Total mass of element

Toxic intake: n.a.

in average 170 kg) person:

Lethal intake: for rabbits, as little as

175 mg kg-1 has proved fatal.

Hazards Elemental sulfur appears to be relatively harmless unless ingested; ignited it emits highly toxic fumes of S02. Sulfur dust is a human eye irritant.

198

140 g

Known to ancient civilizations.

Sulfur

(Sanskrit, sulvere = sulfur; Latin, sulphurium| French, soufre-, German, Schwefel; Italian, solfo\ Spanish, azufre



[sul-fer]

DATA

N (1 CLEAR

Isotope mass range: 29 -> 39

Number of isotopes (including nuclear isomers): 11

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin I

Nuclear magnetic Uses moment p

“S

31.972 070 70

95.02

0+

0

32.97145843

0.75

3/2+

+0.643821

Ms

33.967 866 65

4.21

0+

0

36S

35.967080 62

0.02

0+

0

NMR

A table of radioactive isotopes is given in Appendix 1, on p250.

32S

NMR [Reference: CS2] Receptivity (13C = 1.00) Magnetogyric ratio/rad T's 1 Nuclear quadrupole moment/m2 Frequency ('H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

35g

2.26 x 10'3 0.0973 2.0534 xlO7 -0.678 xlO'28 24.664

Relative sensitivity (*H = 1.00)

0.0471 x 10'28

DATA

Ground state electron configuration: [Ne]3s23p4 Term symbol: 3P2 Electron affinity (M -> M )/k] mol'1: 200.4 Ionization energies/kj mol ':

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M —> M4 M+ —> M24 M24 -» M34 M34 —» M44 M4’ —» M54 M5+ —» M64 M6+ -> M74 M74 —> M84 M84 -4 M94 M94 —> M104

•CRYSTAL

999. 2251 3361 4564 7013 8495 27 106 31669 36 578 43 138

Electron binding energies / eV

K L, Lit l+n

Is 2s 2Pl/2 2p8/2

2472 230.9 163.6 162.5

Main lines in atomic spectrum

[Wavelength/nm(species)] 545.38 (II) 547.36 (II) 550.97 (II) 560.61 (II) 565.99 (II) 792.40 (I) 964.99 (I)

DATA

Crystal structure (cell dimensions/pm), space group

a-S8 orthorhombic (a - 1046.46, b = 1286.60, c= 2448.60), Fddd p-S8 monoclinic (a= 1102, b= 1096, c= 1090, p= 96.7°), P2j/c ^S8 monoclinic (a= 857, b= 1305, c= 823, p= 112° 54'), P2/c e-S6 rhombohedral (a = 646, a= 115° 18'), R3 In addition to the above ring forms there are also S7, S9_12, S18 and S20 rings. Plastic sulfur is long chains of S„ also known in several forms ¥•

/' and «>. T(cx->p) = 366.7 K X-ray diffraction: mass absorption coefficients (p/p)/cm2 g ’: CuKa 89.1 MoKa 9.55 Neutron scattering length, b/10"12 cm: 0.2847 Thermal neutron capture cross-section, cr,/barns:0.53

• GEOLOGICAL Minerals Native sulfur occurs naturally as deposits associated with oil-bearing strata, as in Texas and Louisiana in the USA, and with gypsum (CaS04.2H,0) deposits in Sicily and Italy. Many sulfide and sulfate minerals are known. For sulfides consult antimony (stibnite), lead (galena), mercury (cinnabar), zinc (spharelite), etc. For sulfates see barium (barite), calcium (anhydrite, gypsum), magnesium (epsomite, kieserite), strontium (celestite), etc. The table below shows only those which are used as a source of sulfur. Crystal appearance Density Hardness Mineral Formula orth., met. pale yellow 4.887 6-6.5 Marcasite FeS2 orth., yellow pyramidal 2.07 1.5-2.5 Native sulfur S8 cub., met. dark yellow 5.018 6-6.5 Pyrite FeS2 Chief ores: native sulfur, pyrite; a lot of sulfur is

Abundances

recovered from the H2S of natural gas.

Sun (relative to H = 1 x 1012): 1.6 x 10'

World production/tonnes y'1: 54 x 106 Main mining areas: USA (native sulfur), Spain.

Earth’s crust/p.p.m.: 260 Seawater/p.p.m.: 870

Reserves/tonnes: 2.5xlO9

Residence time /years: 8 x 106 Classification: accumulating

Specimen: available as powder and flake. Safe.

Oxidation state: VI

199

Description: Tantalum is a shiny, silvery metal which is soft when pure. It is very resistant to

corrosion due to an oxide film on its surface, but it is attacked by HF and molten alkalis. Tantalum is used in electronics, cutting tools, chemical plants and surgery. Radii /pm: Ta5* 64; Ta4* 68; Ta3+ 72; atomic 143; covalent 134 Electronegativity: 1.5 (Pauling); 1.33 (Allred); 4.11 eV (absolute) Effective nuclear charge: 3.30 (Slater); 9.53 (Clementi); 13.78 (Froese-Fischer)

Standard reduction potentials E^IV V

Ta205

0 -0.81

Ta

Oxidation states Ta'"1 Ta'1 Ta1 Ta11

d8 d6 d4 d3

[TafCOy3[Ta(CO)6]' (Ta(CO)4(7,-C5H5)] TaO?

Ta” Taw Tav

Melting point/K: 3269

d2 d1 d°[f14]

TaF3, TaCl3, TaBr3 Ta02, TaCl4, TaBr4, Tal4 Ta205, [Tafi019]8" (aq), TaF5, TaCL., [TaFd", [TaF7]2', TaF30, TaFO,

A//fastal/kJ mol'1: 31.4 AH,,,,/kJ moT1: 753.1

Boiling point/K: 5698 ±100

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

AfiP/kJ mol"1 0 782.0

AfG®/kJ mol'1 0 739.3

S*7J K 1 mol"1 41.51 185.214

C„/J K"‘ mol 1 25.36 20.857

Density/kg m"3: 16 654 [293 K]; 15 000 [liquid at m.p.]

Young’s modulus/GPa: 185.7

Molar volume/cm3: 10.87

Rigidity modulus/GPa: 69.2

Thermal conductivity/W m"1 K"1: 57.5 [300 K]

Bulk modulus/GPa: 196.3

Coefficient of linear thermal expansion/K"1:6.6 x 10~t>

Poisson’s ratio/GPa: 0.342

Electrical resistivity In m: 12.45 x 10"s [298 K] Mass magnetic susceptibility/kg"' m3: +1.07 x 10"8 (s)

•BIOLOGICAL

DATA

Biological role

Levels in humans

None.

ingestion

Blood/mg dm"3: n.a., but low Bone/p.p.rn.: C. 0.03 Liver/p.p.m.: n.a. Muscie/p.p.m.: n.a., but low Daily dietary intake: 0.001 mg

Lethal intake: LD50 (chloride, oral, rat) =

Total mass of element

1900 mg kg"1

in average (70 kg) person: C.

Toxicity Toxic intake: moderately poisonous by

Hazards There are no cases of industrial poisoning caused by tantalum or its compounds. However, it is an experimental tumorigen.

200

0.2 mg

Discovered in 1802 by A.G. Ekeberg at Uppsala, Sweden.

Tantalum

[Greek, Tantalos = father of Niobe of Greek mythology] French, tantale; German, Tantai, Italian, tantalio-, Spanish, tdntalo

[tan-ta-lum]

•NUCLEAR Number of isotopes [including nuclear isomers): 28

Isotope mass range: 159 -+ 186

Key isotopes Nuclide

Natural abundance (%)

Atomic mass

,8,Ta*

179.947462

0.012

18lTa

180.947992

99.988

Nuclear spin /

Nuclear magnetic Uses moment /< E

97/2+

+2.371

E, NMR

*'"°Ta is radioactive with a half-life of >1 x 10l3y. A table of radioactive isotopes is given in Appendix 1, on p250.

NMR [Reference: [TaF6]"] Relative sensitivity (' H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T"1s'1 Nuclear quadrupole moment/m2 Frequency (‘H = 100 Hz; 2.3488T)/MHz

• ELECTRON

181Ta 0.0260 204 3.2073 x 107 3.170 xlO'28 11.970

SHELL

Ground state electron configuration: (Xe|4f"5d:i6s2 Term symbol: 4F3/2 Electron affinity (M -+ M )/kJ mol'1: 14 Electron binding energies /eV

Ionization energies/kj mol 1:

1. 2. 3. 4. 5.

M M* M2+ M3+ M1'

^ -> -+ ^ ->

K L,

761 (1500) (2100) (3200) (4300)

M+ M2+ M3+ M4+ M5*

Ln Liu M, Mu Mat

Mlv Mv

Main lines in atomic spectrum

67416 11682 11 136 9881 2708 2469 2194 1793 1735

Is 2s 2Pl/2 2p3/2 3s 3Pl/2 3p3/2 3d3/2 3d5;2

[Wavelength/nm(species)] 240.063 (II) 264.747 (I) 265.327 (I) 271.467 (I) (AA) 285.098 (I) 301.254 (11)

continued in Appendix 2, p257

•CRYSTAL Crystal structure (cell dimensions/pm), space group

b.c.c. (a = 330.29), Im3m X-ray diffraction: mass absorption coefficients (/i/p)/cm2 g'1: CuKa 166 MoK„ 95.4 Neutron scattering length, Z?/10“12 cm: 0.691 Thermal neutron capture cross-section, a,/barns: 20.6

• GEOLOGICAL

DATA

Minerals Mineral Columbite Ferrotantalite Manganotantalite Microlite Samarskite

Density Hardness Crystal appearance Formula a group of ores of mixed composition (Fe,Mn) (Ta,Nb)206 orth., black-brownish/black 6-6.5 7.95 FeTa206 orth., black-brownish/black 6-6.5 6.76 (Fe,Mn)(Ta,Nb)206 cub., vitreous/resinous yellow (Na,Ca)2Ta20r,(0,0H,F) 6.42 5-5.5 orth., vitreous/resinous black 5-6 (Y,Ce,U,Fe)3(Nb,Ta,Ti)50 5.69

Chief ores: columbite, samarskite World production /tonnes y'1:840 Main mining areas: Australia, Zaire, Brazil, Russia,

Norway, Canada, Madagascar; mostly obtained as a by-product of tin extraction. Reserves/tonnes: n.a.

Abundances Sun (relative to H = 1 x 1012): n.a. Earth’s crust/p.p.m.: 2 Seawater/p.p.m.: 2 x 10“6 Residence time/years: n.a. Oxidation state: V

Specimen: available as foil, powder, rod or wire.

Safe.

201

Atomic number: 43 Relative atomic mass (l2C = 12.0000): 98.9063 (Tc-99)

CAS: [7440-26-8]

•CHEMICAL Description: Technetium is a radioactive metal which does not occur naturally on Earth. The

bulk metal is silvery, but it is more commonly obtained as a grey powder. Technetium resists oxidation but slowly tarnishes in moist air, and burns in oxygen. It dissolves in HN03 and H2S04. Radii /pm: Tc7+ 56; Tc4+ 72; Tc2+ 95; atomic 136 Electronegativity: 1.9 (Pauling); 1.36 (Allred); 3.91 eV (absolute) Effective nuclear charge: 3.60 (Slater); 7.23 (Clementi); 10.28 (Froese-Fischer)

Standard reduction potentials ElV VII

VI

V

IV

0.738 1.39

Tc04

-0.569

TcO

2-

TcO,

0.272

TcO,

Tc

-oam tcC)32~ 0.700

0.83

TcOq 0.472

Oxidation states Tc'1 Tc° Tc1

d8 d7 d6

Tclv

[Tc(CO)5]' [Tc2(CO)10] [Tc(CO)3(n-C5H5)]

Tcv Tc" Tc"1

•PHYSICAL

d3

Tc02, [Tc03]2' (aq), TcCl4, complexes d2 [Tc03]" (aq), TcC15, complexes Tc03 ?, TcF6, TcC140, d1 complexes d° [Kr] Tc207, [Tc04]' (aq), TcC103, complexes

DATA

Melting point/K: 2445

mol23.81 A//vap/k] mol'1: 585.22

Boiling point/K: 5150

Thermodynamic properties (298.15 K, o.l MPa) State Solid Gas

AfM 137

Key isotopes Nuclide

Atomic mass

Natural abundance(%)

Nuclear spin /

Nuclear magnetic Uses moment p E

l2“Te

119.904 048

0.09

0+

,22Te

121.903 050

2.57

0+

l23Te*

122.904271

0.89

1/2+

l24Te

123.902 818

4.76

0+

125Te

124.904 428

7.10

1/2+

E -0.73679

E, NMR

-0.88828

E, NMR

E

,2STe

125.903 309

18.89

0+

E

12*Te

127.904463

31.73

0+

E

l30Te**

129.906229

33.97

0+

E

*123Te is radioactive with a hall-life of 1.3 x 1013 y and decay mode EC {0.052 MeV); no ««i3«Te is also radioactive with a half-life of 2.4 x 1021 y. A table of other radioactive isotopes is given in Appendix 1. on p250.

NMR [Reference: Te(CH3)2]

123Te 0.0180 0.89 -7.0006x10'

125Te 0.0315 12.5 -8.4398x10'

-

-

26.207

31.596

Relative sensitivity (!H = 1.00) Receptivity (l3C= 1.00) Magnetogyric ratio/rad T's-1 Nuclear quadrupole moment/ m2 Frequency ('H = 100 Hz; 2.3488T)/MHz

•ELECTRON

SHELL

y.

DATA

Ground state electron configuration: [Kr]4dl05s25p4 Term symbol: 3P2 Electron affinity (M -> M )/k) mol-1: 190.2 miration enereies/kl mol 1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M* M2+ M3" M4* M5* M6+ M7* M8f M9+

869.2 M+ 1795 M2+ 2698 M3+ 3610 M4* 5668 M5+ 6822 M6+ 13200 M7+ m8+ (15 800) ^ M9+ (18 500) -+ M10+ (21 200)

-> ^ ^ -+ ^ ^ ^

Main lines in atomic spectrum

Electron binding energies/eV

K L, L,, I+n M, M„ Mm M,v Mv

[Wavelength/nm(species)l

31814 4939 4612 4341 1006 870.8 820.0 583.4 573.0

Is 2s 2Pl/2

2p3/2 3s 3Pl/2

3p3/2 3d3/2 3d3/2

200.202 (I)

214.281 (I) (AA) 972.274 (I) 1005.141 (I) 1108.956 (I) 1148.723 (I)

continued in Appendix 2, p257

•CRYSTAL Crystal structure (cell dimensions/pm), space group

hexagonal (a = 445.65, c= 592.68), P3,21 or P3221 High pressure forms: [a = 420.8, c= 1203.6), R3m; (a = 460.3, c= 382.2), R3m X-ray diffraction: mass absorption coefficients (p/p)/cm2 g ': CuKa 282 MoKa 35.0 Neutron scattering length, h/10'12 cm: 0.580 Thermal neutron capture cross-section, a ,,/barns: 4.7

• GEOLOGICAL Minerals Mineral Sylvanite Tellurite

Formula AgAuTe, TeO,

Density 8.16 5.90

Hardness 1.5-2 2

Crystal appearance mon., met. grey orth., sub-adamantine white

Chief ores: none mined as such. Tellurium is

Abundances

obtained from the anode slime of copper refining.

Sun (relative to H = 1 x 1012): n.a.

World production/tonnes y1:215 Areas where minerals found: sylvanite in Australia,

USA and Romania Reserves/tonnes: n.a. Specimen: available as granules, ingots, pieces or

powder. Danger!

Earth’s crust/p.p.m.: c. 0.005 Seawater/p. p.m.:

Atlantic surface: 1.6 x 10 7 Adantic deep: 0.7 x 10 ' Pacific surface: 1.9 x 10-7 Pacific deep: 1.7 x 10*' Residence time/years: n.a. Classification: scavenged Oxidation state: IV and VI; mainly VI

205

.

CAS: [7440-27-9]

Atomic number: 65 Relative atomic mass (!2C = 12.0000): 158.92534

•CHEMICAL Description: Terbium is a silvery metal, and a particularly rare member of the so-called rare

earth group (more correctly termed the lanthanides). It is slowly oxidised by air and reacts with cold water. Terbium is used in solid state devices and lasers. Radii/pm: Tb4+ 81; Tb3* 97; atomic 178; covalent 159 Electronegativity: n.a. (Pauling); 1.10 (Allred); < 3.2 eV (absolute) Effective nuclear charge: 2.85 (Slater); 8.30 (Clementi); 11.39 (Froese-Fischer)

Standard reduction potentials ElV IV 4-

III 3.1

O,

0 -2.31

acid

Tb4 -Tb3+-Tb

base

Tb02 — Tb(OH)3 —-Tb

09

—2 82

Oxidation states Tb111

fs

Tbn/

f7

Tb203, Tb(OH)3, [Tb(OH2)j3+ (aq), Tb3+ salts, TbF3, TbCl,, complexes Tb02, TbF4

Melting point/K: 1629

AW fusion /kj mol ': 16.3 AWvap/kJ mol-1: 391

Boiling point/K: 3396

Thermodynamic properties (298. State Solid Gas

Af//e/kJ mol1 0 388.7

K, 0.1 MPa) AfG®/kJ mol'1 0 349.7

Se/J K1 moT1 73.22 203.58

C„/J K 1 mol 1 28.91 24.56

Density/kg m 3: 8229 [293 K]

Young’s modulus/GPa: 55.7

Molar volume /cm3: 19.31

Rigidity modulus/GPa: 22.1

Thermal conductivity/W m~1 K'1: 11.1 [300 K]

Bulk modulus/GPa: 38.7

Coefficient of linear thermal expansion/K1:7.0 x 10-6

Poisson’s ratio/GPa: 0.261

Electrical resistivity In m: 114

10-8 [298 K] Mass magnetic susceptibility/kg 1 m3: +1.15 x 10 5 (s) x

•BIOLOGICAL

DATA

Biological role

Levels in humans

None.

Organs:

Toxicity

Daily dietary intake:

Toxic intake: n.a. Lethal intake: LD50 (chloride, oral, mouse) =

> 5100 mg kg-1

Hazards Terbium is mildly toxic by ingestion, and is a skin and eye irritant.

206

n.a., but low n.a.

Total mass of element in average (70 kg) person:

n.a., but very low

Number of isotopes (including nuclear isomers): 31

Isotope mass range: 145 -> 165

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear spin I

Nuclear magnetic Uses moment p

l59Tb

158.925342

100

3/2+

+2.014

NMR

A table of radioactive isotopes is given in Appendix 1. on p250.

NMR [Reference: not recorded]

l59Tb 0.0583 394 6.4306x10' +1.432 x 10 28 22.678

Relative sensitivity (*H = 1.00) Receptivity (13C = 1.00) Magnetogyric ratio/rad T’s-1 Nuclear quadrupole moment/m2 Frequency (‘H = 100 Hz; 2.3488T)/MHz

• ELECTRON

SHELL

Ground state electron configuration: [Xe]4f6s2 Term symbol: bH,5;2 Electron affinity (M -> M")/kJ mol1: < 50 Ionization energies/kl mol l:

1. 2. 3. 4. 5.

M M” M2+ M3t M4>

-+ -> -> -+ -+

M+ M2+ M3t M4+ M5+

564.6 1112 2114 3839 6413

Electron binding energies / eV

K L,

Is 2s

Lu

2pi/2

Liu

2p3/2

M, M„ Mm

3s

51996 8708 8252 7514 1968 1768 1611 1276.9 1241.1

3Pl/2

Mjv

3P3/2 3d3,2

Mv

3d5,2

Main lines in atomic spectrum

[Wavelength/nm(species)] 332.440 (II) 350.917 (II)

356.852 (II) 367.635(11) 370.286 (II) 384.873 (II) 387.417 (II) 432.643 (I) (AA)

continued in Appendix 2, p257

•CRYSTAL Crystal structure (cell dimensions/pm), space group

Tb orthorhombic (a = 359.0, b= 626.0, c= 571.5), Cmcm a-Tb h.c.p. (a= 360.10, c= 569.36), P63/mmc /?-Tb b.c.c. (a = 402), Im3m T(a -> orthorhombic) = 220 K; T(a —+/?) = 1590 K X-ray diffraction: mass absorption coefficients [p/p)lcm2 g 1: CuK[( 273 MoKa 67.5 Neutron scattering length, fe/10-12 cm: 0.738 Thermal neutron capture cross-section, 9. M8‘ -> 10. M9* ->

M* 589.3 M2+ 1971.0 M3+ 2878 M4+ (4900) M5+ (6100) M6" (8300) M7+ (9500) M8+ (11300) M9* (14 000) M10t (16 000)

Electron binding energies/eV

K L, L„ f+u M, Mu Mm MIV Mv

85 530 15 347 14 698 12 658 3704 3416 2957 2485 2389

Is 2s 2Pl/2 2p3/2 3s 3Pl/2 3p3/2 3d3/2 3d5/2

Main lines in atomic spectrum

[Wavelength / nm(species) ] 276.787 d) (AA) 291.832 (I) 351.924 (I) 352.943 (I) 377.572 0) 535.046 (I)

continued in Appendix 2, p257

•CRYSTAL Crystal structure (cell dimensions/pm), space group

ct-Tl hexagonal (a = 345.6, c= 552.6), P63/mmc /3-T1 cubic (a = 388.2), Im3m y-Tl f.c.c. (a = 485.1), Fm3m 1\a ->p) = 503 K X-ray diffraction: mass absorption coefficients (p/p)/cm2 g"1: CuKa 224 MoKc, 119 Neutron scattering length, h/10"12 cm: 0.8776 Thermal neutron capture cross-section, /10'12 cm: 0.707 Thermal neutron capture cross-section, ,+,/barns: 100

•GEOLOGICAL

DATA

Minerals Mineral

Formula

Bastnasite* Monazite*

(Ce,La, etc)C03F (Ce, La, Nd, Th, etc)PO„

Density Hardness Crystal appearance

4.9 5.20

4-4.5 5-5.5

hex., vit./greasy yellow mon„ waxy/vit. yellow-brown

‘although not a major constituent, thulium is present in extractable amounts. Chief ores: monazite, bastnasite World production /tonnes y"1: C. 50 Main mining areas: USA, Brazil, India, Sri Lanka,

Australia Reserves/tonnes: c.lx 105 Specimen: available as chips, ingots or powder.

Safe.

Abundances Sun (relative to H = 1 x 1012): 1.8 Earth’s crust/p.p.m.: 0.48 Seawater/p.p.m.:

Atlantic surface: 1.3 x 10"7 Atlantic deep: 1.6 x 10'7 Pacific surface: 0.7 x 10'7 Pacific deep: 3.3 x 10'7 Residence time/years: n.a. Classification: recycled Oxidation state: Ill

213

CAS:

Atomic number: 50 Relative atomic mass (i2C= 12.0000): 118.710

• CHEMICAL

[7440-31-5]

DATA

Description: Tin is a soft, pliable, silvery-white metal that is unreactive to oxygen (protected

by an oxide film on the surface) and water. It dissolves in acids and bases. Tin is used in solder, alloys, tin plate, polymer additives and some anti-fouling paints. Radii/pm: Sn4+ 74; Sn2* 93; Sn4" 294; atomic 141; covalent 140; van der Waals 200 Electronegativity: 1.96 (Pauling); 1.72 (Allred); 4.30 eV (absolute) Effective nuclear charge: 5.65 (Slater); 9.10 (Clementi); 11.11 (Froese-Fischer)

Standard reduction potentials El\r IV acid

II -0.088 „



-IV

0 -0.104

-1.071

Sn02_ -SnO-Sn- SnH4 Sn4+~

0.15

Sn2

-0.137

[basic solutions contain many different forms]

Oxidation states

Covalent bonds

Sn"

s2

SnIV

d10

Bond Sn—H Sn—C Sn"—O Sn™—F Snlv—Cl Sn™—Br Sn™—I Sn—Sn (a)

SnO, SnF2, SnCl2 etc., [Sn(OH)]+ (aq), [Sn3(OH)4]2+ (aq), Sn2+ salts Snd2, SnF4, SnCl4 etc., [SnCl6]2" (aq HC1), [Sn(OH)6]2_ (aqbase), organotin compounds

•PHYSICAL

rl pm 170 217 195 188 233 246 269 281

El kj mol

—> —>

—> -> —> —> —>

M+ M2‘ M3+ M4‘ M5+ Ms‘ M7* M8+ M9* M10t

658 1310 2652 4175 9573 11516 13 590 16 260 18 640 20 830

Electron binding energies / eV

K L, Lu I+n M, M„ M,„

Is 2s 2pi/2 2P3/2 3s 3Pl/2 3P3/2

Main lines in atomic spectrum

[Wavelength/nm(species)] 323.452 (II) 334.941 (II) 336.121 (II) 364.268 (1) 365.350 (I) (AA) 399.864 (I)

4966 560.9 460.2 453.8 58.7 32.6 32.6

•CRYSTAL Crystal structure (cell dimensions/pm), space group

a-Ti h.c.p. (a = 295.11, c= 468.43), P63/mmc /3-Tib.c.c. (a = 330.65), Inr3m Tla -+/?) = 1155 K High pressure form: (a = 462.5; c= 281.3), P3ml X-ray diffraction: mass absorption coefficients (/z/p)/cm2 g"1: CuKa 208 MoKn 24.2 Neutron scattering length, b/10"12 cm: -0.3438 Thermal neutron capture cross-section, +a/barns: 6.09

•GEOLOGICAL Minerals Mineral Anatase Brookite Ilmenite Perovskite* Rutile Titanite

Formula p-Ti02 Y-Ti02 FeTi03 CaTiCh a-Ti02 CaTiSi05

Density 3.90 4.14 4.72 4.01 4.23 3.50

Hardness 5.5-6 5.5-6 5-6 5.5 6-6.5 5-5.5

Crystal appearance tet., adam./brown, green, etc. orth., met. adam./brown, black rhorn. met. black orth., adam./met. black tet., met. lustre brown/yellowish mon., adam./res. yellow/brown

‘Varieties of perovskite can be rich in niobium, cerium and other rare earth elements and may be a source of these metals. Chief ores: ilmenite; sometimes anatase is mined World production/tonnes y"1: 99 000 (titanium

metal); 3 x 106 (Ti02) Main mining areas: Norway, India, Brazil, Canada, USA, Russia Reserves /tonnes: 440 x 106

Abundances Sun (relative to H = 1 x 1012): 1.12 x 105 Earth’s crust /p.p.m.: 5600 Seawater/p.p.m.: 4.8 x 10"4 Residence time/years: 50 Classification: n.a. Oxidation state: IV

Specimen: available as crystals, foil, granules,

powder, rod or wire. Safe.

217

w

Atomic number: 74

CAS:

Relative atomic mass (i;'C = 12.0000): 183.84

• CHEMICAL

[7440-33-7]

DATA

Description: Tungsten is generally obtained as a dull grey powder, which is difficult to melt. The bulk metal is lustrous and silvery white, and resists attack by oxygen, acids and alkalis. Tungsten is used in alloys, to which it imparts great strength, in light bulb filaments and cutting tools. Radii/pm: W6* 62; W4t 68; atomic 137; covalent 130 Electronegativity: 2.36 (Pauling); 1.40 (Allred); 4.40 eV (absolute) Effective nuclear charge: 4.35 (Slater); 9.85 (Clementi); 14.22 (Froese-Fischer)

Standard reduction potentials £"7V VI

V

IV

0

-0.090 -0.029

acid

-0.031

-0.119

W03-W205-W02-W -1.074 -0.982 - wo2--W

-1.259

base

IWO4J

Oxidation states w-|V

W-"

w' w> W'

d'° d8 d7 d6 d5

[WfCO)/ [W(CO)5]2[W2(CO)10]2[W(CO)J [W(CO)3(n-C5H5)]2

W"'

d4 d3 d2

wv

d1

Ww

d°[f'4]

w“

WC12, WBr,, WI2, complexes WC13, WBr3, WI3, complexes W02, WF3, WCh etc., WS2, complexes W205, WF5, WC15, [WFJ-, complexes W03, [W04]2-, WF6, WC16, WC146, polytungstates, complexes

IThere are no aqua ions of W in any oxidation state.]

•PHYSICAL

DAT

Melting point / K: 3680 ±20

AHfuston/kJ mol *: 35.2 AWvap/kJ moT': 799.1

Boiling point/K: 5930

Thermodynamic properties (298. State Solid Gas

AffT/kJ moT1 0 849.4

K, 0.1 MPa) AfGe/kJ moT1 0

807.1

Se/J K-1 mol1 32.64 173.950

C„/J K 1 moT1 24.27 21.309

Density/kg nv1: 19 300 [293 K]; 17 700 [liquid at m.p.J Molar volume/cm3: 9.53

Young’s modulus/GPa: 411

Thermal conductivity/W m1 K"1: 174 [300 K]

Bulk modulus / GPa: 311

Coefficient of linear thermal expansion/K1:4.59 x 10"*’

Poisson’s ratio/GPa: 0.28

Rigidity modulus/GPa: 160.6

Electrical resistivity/a m: 5.65 x 10-8 [300 K] Mass magnetic susceptibility/kg 1 m3: +4.0 x 109 (s)

LOGICAL Biological role

Levels in humans

None.

Blood/mg dm"3:0.001

Toxicity Toxic intake: mildly toxic

Bone/p.p.m.: 0.00025 Liver/p.p.rn.: n.a. Muscle/p.p.m.: n.a.

Lethal intake: LD50 (metal, rat) = 2000 mg kg1

Daily dietary intake: 0.001 - 0.015 mg

Hazards

Total mass of element

Tungsten dust is a skin and eye irritant, and an experimental teratogen.

218

in average (70 kg) person: C. 0.02 mg

Discovered in 1783 by J.J. and F. Elhuijar at Vergara, Spain.

Tungsten

[Swedish, tungsten = heavy stone; wolfram is named after wolframite] French, tungst≠ German, Wolfram; Italian, wolframio (tungsteno); Spanish, wolframio

Itung-sten]

•NUCLEAR Number of isotopes (including nuclear isomers): 29

Isotope mass range: 160 -> 190

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

180W '82W

179.946 701

1BW

182.950220

14.3

1/2-

1MW I sew

183.950928

30.7

0+

E

185.954 357

28.6

Of

E

Nuclear spin /

0.12

181.948 202

26.3

Nuclear magnetic Uses moment u

0+

E

Q+

E +0.1177847

E, NMR

A table of radioactive isotopes is given in Appendix 1, on p252.

NMR [Reference: WF6]

Magnetogyric ratio / rad T_1 s'1

183W 7.20 x 10"4 0.0589 1.1154xl07

Nuclear quadrupole moment/ m2

-

Frequency (‘H = 100 Hz; 2.3488T)/MHz

4.161

Relative sensitivity ('H = 1.00) Receptivity (13C = 1.00)

•ELECTRON

SHELL

DATA

Ground state electron configuration: [Xe]4f145d‘16s2 Term symbol: 5D0 Electron affinity (M -> M )/kJ mol'1: 78.6 Ionization energies/kj mol1:

1. 2. 3. 4. 5. 6.

M M4 M2* M3+ M4* M5+

—> -> —> —>

M4 M24 M34 M44 M34 M64

Electron binding energies/eV

770 (1700) (2300) (3400) (4600) (5900)

K L, Ln Lin M, M„ MUI MIV Mv

Main lines in atomic spectrum

[Wavelength/nm(species)l 202.998 (II) 207.911(11) 255.135 (I) (AA) 400.875 (I) 407.436 (I) 429.461 (I)

69 525 12100 11544 10207 2820 2575 2281 1949 1809

Is 2s 2Pl/2 2P3/2 3s 3Pl/2 3p3/2 3d3/2 3d5/2

continued in Appendix 2, p258

•CRYSTAL Crystal structure (cell dimensions/pm), space group

b.c.c. (a = 316.522), Im3m X-ray diffraction: mass absorption coefficients (/i/p) / cm2 g ’: CuKn 172 MoK„ 99.1 Neutron scattering length, bl 10~12 cm: 0.486 Thermal neutron capture cross-section, a,/barns: 18.3

•GEOLOGICAL

DATA

Minerals Mineral Ferberite Scheelite Wolframite

Formula FeWO, CaWO„ (Fe,Mn)W04

Density 7.40 6.10 7.3

Hardness 4-4.5 4.5-5 4-4.5

Chief ores: scheelite and wolframite World production /tonnes y"': 45 100 Main mining areas: China, Malaysia, Burma,

Crystal appearance mon., met. black tet., vit./adam. colourless mon., sub-met./adam. greyish-black

Abundances Sun (relative to H = 1 x 1012): 50 Earth’s crust/p.p.m.: 1

Bolivia, Canada, Australia, Japan, USA

Seawater/p.p.m.: 9.2 x 10'5 Residence time/years: n.a.

Reserves/tonnes: 1.5 xlO6

Oxidation state: VI

Specimen: available as foil, powder, rod or wire.

Safe.

219

Atomic number: 92

CAS:

Relative atomic mass (l2C = 12.0000): 238.0289

• CHEMICAL

[7440-61-1)

DATA

Discovery: Uranium was discovered in 1789 by M.J. Klaproth at Berlin, Germany. It was first

isolated as the metal in 1841 by W. M. Peligot at Paris, France. Description: Uranium is a silvery, ductile, malleable, radioactive metal. It tarnishes in air and

is attacked by steam and acids, but not by alkalis. Uranium is used as nuclear fuel and in nuclear weapons. Radii/pm: U6t 80; U5+ 89; U4+ 97; U3+ 103; atomic 154; Electronegativity: 1.38 (Pauling); 1.22 (Allred); n.a. eV (absolute) Effective nuclear charge: 1.80 (Slater)

Standard reduction potentials E1V VI

V

IV

III

-0.027

acid

uo22+

uo2

+

-1.38

-0-38

-0.3 U(0H)202-

base

0

y4+

-0-52

^3+

-1-66

-2.6

u

-2.10

U02-U(OH)3- u

states U“ U1"

f3d‘ f3

UO? [U(OH2)J3* (aq) unstable, UF3, UC13 etc., [U(C5H5)3] U™ f2 UO,, [U(OH2)J4+ (aq) and salts, UF4, UC14 etc., [UC16]2-, [U(C5H5)4] Uv f1 U205, U02’ (aq) unstable, UF5, UC15, UBr5, [UF6]-, [UF7]2”, [UFJ3" UVI [Rnj U03, UO,24 (aq) and salts, UF6, UC16, complexes Mixed valence oxides: U409, U307, U3Os

•PHYSICAL Melting point/K: 1405.5

Al/^/kJ mol *: 15.5 A//vap/kJ mol”1: 422.6

Boiling point/K: 4018

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

A(H^lk) mol”' 0 535.6

AfG®/kJ mol”1 0 491.2

S 12)

2.19

V04

HV205

0.542

-0.486

-0.820

v2o3 -VO- V

0.749

Oxidation states vm V-'V° V1 V"

d8 d6 d5 d4 d3

rare [V(CO)5]^ [V(CO)6r [V(CO)6] [V(dipyridyl)3] + VO, [V(OH2)6]2+ (aq), VF2, VC12, complexes

•PHY S 1 C A L

V"1 V,v Vv

d2

VA, [V(OH2)6]3* (aq), VF:!, VC1„ rvo,]d1 V02,V02* (aq), VF.,, VC14, complexes d° [Ar] V205, V02+ (aq), VO/- (aq alkali), VFS, [VF6] , complexes

nnraiB

Melting point/K: 2160

AWf^/k] mol"': 17.6 A«vap/kJ mol-1: 458.6

Boiling point / K: 3650

Thermodynamic properties (298.15 K, 0.1 MPa) State Solid Gas

AfH®/kJ mol-1

AfG*7kJ mol-1

0

0

514.21

754.43

S —> -> —> —> —> —> —> —>

650 M4 1414 M24 M3+ , 2828 4507 M4’ 6294 M5+ 12 326 M6t 14489 M7* 16 760 M8+ 19 860 M94 22 240 M'0+

Electron binding energies / eV

Is 2s 2pu2 2p3/2 3s 3pi/2 3p3«

K L, Ln Liu

M, M,i M,n

5465 626.7 519.8 512.1 66.3 37.2 37.2

Main lines in atomic spectrum

[Wavelength/nm(species)] 318.398 (I) 318.540 (I) (AA) 411.178(1) 437.924 (I) 438.472 (I) 399.864 (I)

•CRYSTAL Crystal structure (cell dimensions/pm), space group

b.c.c. (a = 302.40), Im3m X-ray diffraction: mass absorption coefficients (p/p)/cm2 g"1: CuKa 233 MoK„ 27.5 Neutron scattering length, b/10"12 cm: -0.0382 Thermal neutron capture cross-section, cr,/barns:5.08

•GEOLOGICAL Minerals Vanadium occurs in many minerals. Mineral Carnotite Descloizite Patronite Vanadinite

Formula K2(U02),(V04)2.3H20 PbZn(V04)(OH) vs4 Pb5(V04)3Cl

Density Hardness Crystal appearance mon., dull/earthy/pearly yellow 4.95 n.a.* 6.2 3-3.5 orth., greasy brown/red mon., grey-black 2.81 2 6.86 2.7-3 hex., sub-res./sub-adam. orange/red

*soft Chief ores: descloizite, patronite, vanadite,

Abundances

carnotite.

Sun (relative to H = 1 x 1012): 1.05 x 104

World production/tonnes y'1:7000

Earth’s crust/p.p.m.: 160 Seawater/p.p.m.:

Main mining areas: not mined as such, but generally obtained as a by-product of other ores, and from Venezuelan oils. Reserves/tonnes: n.a. Specimen: available as foil, granules, powder, r°d

or turnings. Care!

Atlantic surface: 1.1 x 10“3 Atlantic deep: n.a. Pacific surface: 1.6 x 10 3 Pacific deep: 1.8 x 10"3 Residence time /years: 50 000 Classification: recycled Oxidation state: V

223

Xe

Atomic number: 54 Relative atomic mass (12C = 12.0000): 131.29

• CHEMICAL

CAS: [7440-63-3]

DATA

Discovery: Xenon was discovered in 1898 by Sir William Ramsay and M.W. Travers at London,

England. Description: Xenon is a colourless, odourless gas obtained from liquid air. It is inert towards

all other chemicals except fluorine gas, with which it reacts to form xenon fluorides. From these a range of other compounds, such as oxides, acids and salts can be made. Xenon has little commercial use, but in research it is employed as a supercritical fluid in various ways. Radii /pm: Xe+190; atomic 218; covalent 209; van der Waals 216 Electronegativity: 2.6 (Pauling); 2.40 (Allred); 5.85 eV (absolute) Effective nuclear charge: 8.25 (Slater); 12.42 (dementi); 15.61 (Froese-Fischer)

Standard reduction potentials ElV VIII

IV

II

I

0

2.18

acid

2.12

H4Xe06-Xe03—•

Xe

0.9

XeF2

3.4

XeF 2.32

,

base

0.99

1.24

Xe

[HXe06r -[HXe04]“ 1.18

Oxidation states

Covalent bonds

Xe°

[Xe]

Xe" Xe" Xevl

s2p4 s2p2 s2

Bond Xe'1—O Xevl—F

Xe™1 d10

ciathrates: Xe8(OH2)46, Xe(quinol)3 (see argon) XeF2, [XeF]+[AsF6]“ XeF4 Xe03, XeF40, XeF202, XeF6, [XeF7]', [XeF„]2', [XeF5]+[AsF6]' Xe04, XeF203, Ba2Xe06, [XeOg]4- (aq)

•PHYSICAL

r/ pm 176 190

El kj mol'1 84 126

DATA

Melting point/K: 161.3

AW^/kJ mol'1: 3.10

Boiling point/K: 166.1

AW»ap/kJ mol"1: 12.65

Critical temperature/K: 289.75 Critical pressure/ kPa: 5895

Thermodynamic properties (298.15 K, o.i MPa) State Gas

AfFr/kJ mol 1 0

AfGe/kJ mol'1 0

S9/J K1 mol1 169.683

C„/J K 1 mol'1 20.786

Density/kg m"3: 3540 [s„ m.p.]; 2939 [liq, b.p.]; 5.8971 [gas, 273 K] Molar volume/cm3: 37.09 [161 K] Thermal conductivity/W m"1 K"1: 0.00569 [300 K] (g) Mass magnetic susceptibility/kg"1 m3: -4.20 x 10"9 (g)

BIOLOGICAL Biological role None.

Toxicity Non-toxic.

Hazards Xenon is a harmless gas, although it could asphyxiate if it excluded oxygen from the lungs.

224

Levels in humans Blood/mg

dm'3: trace nil Liver/p.p.rn.: nil Muscle/p.p.m.: nil Daily dietary intake: 11.a. but low Bone/p.p.m.:

Total mass of element in average (70 kg) person:

n.a., but small

Discovery: see Chemical Data section.

Xenon

(Greek, xenos = stranger] French, x4non-, German, Xenon-, Italian, xeno; Spanish, xendn

•NUCLEAR

Izee-non]

DATA

Number of isotopes (including nuclear isomers): 35

Isotope mass range: 114 -> 142

Key isotopes Nuclide

Atomic mass

Natural abundance (%)

Nuclear magnetic Uses moment p

Nuclear spin /

124Xe

123.905 894

0.10

“Xe

125.904 281

0.09

0+ 0+

128Xe

127.903 531

1.91

0+

129Xe

128.904 780

26.4

,30Xe

129.903 509

4.1

1/2+

131Xe

130.905 072

21.2

3/2+

132Xe

131.904 144

26.9

0+

-0.777977

NMR

+0.6868

NMR

0+

133.905 395 10.4 0+ l3,Xe 135.907214 8.9 0+ 136Xe A table of radioactive isotopes is given in Appendix 1, on p252.

NMR [Reference: XeOF4]

129Xe

Relative sensitivity (’H = 1.00)

0.0212

Receptivity (13C = 1.00)

31.8 -7.4003 x 107

Magnetogyric ratio/rad T's'1

-0.120 x 10"28

Nuclear quadrupole moment/m2

27.660

Frequency (‘H = 100 Hz; 2.3488T)/MHz

•ELECTRON

l31Xe 2.76 xl0“3 3.31 2.1939 x 107 8.199

SHELL

Ground state electron configuration: [Kr]4d'°5s25p6 = [Xe] Term symbol: 'S0 Electron affinity (M -> M )/k| mol-1: -41 (calc.) Electron binding energies / eV

Ionization energies/kj mol

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M M* M2+ M3" M4+ M5" M6t M7’ M8+ M9’

—» —> —> —> —> —» —> —> —> —»

M+ M2’ M3" M4" M5t M6* M7+ M8* M9+ M,0+

1170.4 2046 3097 (4300) (5500) (6600) (9300) (10 600) (19 800) (23 000)

K L, Lii

I+n M, M„ MnI M,v Mv

Is 2s 2pi/2 2P3/2 3s 3Pl/2 3P3/2 3d3/2 3d5;2

34561 5453 5107 4786 1148.7 1002.1 940.6 689.0 676.4

Main lines in atomic spectrum

[Wavelength/nm(species)] 823.164 (I) 828.012 (II) 881.941 (II) 3106.923 (I) 3507.025 (I)

continued in Appendix 2, p258

•CRYSTAL Crystal structure (cell dimensions/pm), space group

f.c.c. (88 K) {a = 619.7), Fm3m X-ray diffraction: mass absorption coefficients (p/p)/cm2 g

CuK0 306 MoKa 39.2

Neutron scattering length, bl 10'12 cm: 0.492 Thermal neutron capture cross-section, M )/kj mol'1: 41.1 Ionization energies/kj mol'1:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

M —> M* —» M2t M2+ —> M3+ M3* —> M4+ —> M5+ M5t —» M6+ M6* —> M7* M7+ —> M8+ M8* —> M9* M9+ —> M107

Electron binding energies /eV

K L,

660 1267 2218 3313 7860 (9500) (11200) (13800) (15700) (17500)

•CRYSTAL

Ln

M, M„ Mln Mw Mv

17998 2532 2307 2223 430.3 343.5 329.8 181.1 178.8

Is 2s 2pi/a 2p3/2 3s 3p,/2 3p3/2

3d3/2 3d5/2

Main lines in atomic spectrum

[Wavelength/nm(species)] 339.198 (II) 343.823 (II) 349.621 (II) 360.119 (I) (AA) 389.032 (I)

continued in Appendix 2, p258

DATA

Crystal structure (cell dimensions/pm), space group

a-Zr h.c.p. (a = 323.21, c= 514.77), P63/mmc p-Zr b.c.c. (a = 361.6), lm3m T[a -»/3) = 1135 K High pressure form: (a = 503.6, c= 310.9), P3ml X-ray diffraction: mass absorption coefficients (p/p)/cm2 g'1: CuK0 143 MoKa 15.9 Neutron scattering length, bl 10"’2 cm: 0.716 Thermal neutron capture cross-section, rr./barns: 0.184

• GEOLOGICAL Minerals Mineral Baddeleyite Zircon

Formula Zr02 ZrSi04

Density 5.82 4.7

Hardness 6.5 7.5

Chief ores: zircon, baddeleyite World production /tonnes y'1: 7000 (Zr metal);

7 x 105 (zircon)

Crystal appearance mon., greasy/vit. col./ yellow/ green tet., stubby crystals, colourless/yellow/grey

Abundances Sun (relative to H = 1 x 1012): 560 Earth’s crust/p.p.m.: 190

Main mining areas: Australia, Brazil, USA, Sri Lanka

Seawater/p.p.m.: 9 x 10"6 Residence time /years: n.a.

Reserves/tonnes: > 1 x 109

Oxidation state: IV

Specimen: available as foil, powder, rod or wire.

Safe.

233

APPENDIX 1

Radioactive isotopes of the elements There is an entry for every element in this appendix although not all the information about radioactive isotopes is to be found herein. Elements with naturally-occurring radioactive isotopes have these included in the table in the main section of the book. Elements for which all the isotopes are radioactive also have them listed in the main section - these are mainly the transuranium elements. The tables in the main section, and in this appendix, give only the longer lived isotopes of the other elements, and a footnote to either table indicates the maximum half life of other short-lived isotopes. The sources of the data are given in the Key. Uses: the abbreviations are R = research, D = medical diagnosis,T = medical therapy.

Actinium Isotopes of actinium with half-lives longer than 10 minutes are given in the main table on page 17.

Aluminium/Aluminum (US) Nuclide

Atomic mass

Half life (T„2)

26A1

25.986892

28A1

27.981910

7.2 x 105y 2.25 m

28A1

28.980446

6.5 m

Nuclear Nuclear magnetic spin / moment fi

Uses

p* (4.005) 82%; EC, 18%; y

5+

R

p~ (4.642); y

3+

P' (3.68); y

5/2+

Decay mode and energy (MeV)

3.24

Other radioisotopes of aluminium have half-lives shorter than 10 seconds.

Americium Isotopes of americium with half-lives longer than 1 hour are given in the main table on page 21.

Antimony Nuclide

Atomic mass

"sSb

118.903948

l2“Sb l2°mSb

119.903821

l22Sb

121.905 179

Decay mode and energy (MeV)

Nuclear Nuclear magnetic spin / moment fi

38.1 h

EC (0.59); Y

5/2+

+3.45

15.89 m

p* (2.68) 41%; EC 59%; y

1+

+2.3

5.76 d

8-

2.34

2.73 d

EC; y p~ (1.9820) 98%; p+ (0.619) 2%; y

2-

-1.90

Half life (T„2)

,24Sb

123.905038

60.30 d

p- (2.905); Y

3-

1.2

125Sb

124.905252

2.758 y

7/2+

+2.63

,26Sb

125.907250

12.4 d

P“ (0.767); y P"(3.67); Y

8-

13

,27Sb

126.906919

3.84 d

p- (1.58); r

7/2+

2.6

Uses

R

Other radioisotopes of antimony have half-lives shorter than 1 day.

Argon Nuclide

Atomic mass

Half life (T„z)

Decay mode and energy (MeV)

Nuclear Nuclear magnetic spin / moment p

37Ar

36.966776

35.0 d

EC (0.814); no y

3/2+

+1.15

39Ar

38.962314

268 y

p~ (0.565); no y

7/2-

-1.3

11 Ar

40.964501

1.82 h

41.963050

33 y

p'(2.492); Y P' (0.60); no y

7/2-

42 Ar 41 Ar

43.963650

11.87 m

p~ (3.54); Y

0+

Uses

R

0+

Other radioisotopes of argon have half-lives of less than 10 minutes. 235



mm

'' Kp , HHSHHHHUBHHHI pun

Hm—

Arsenic Nuclide

Atomic mass

Half life (T,«)

Decay mode and energy (MeV)

Nuclear Nuclear spin magnetic l moment n

7'As

70.927114

2.72 d

p7 (2.013) 32%; EC 68%; y

5/2-

+1.6735

"As

71.926755

26.0 h

p+ (4.355) 77%; y

2-

-2.1566

"As

72.923 827

80.3 d

EC (0.346); y

3/2-

"As

73.923827

17.78 d

p- (2.562) 31%; EC 37%; p- (1.354); y

2-

-1.597

76As

75.922393

26.3 h

P~ (2.97); y

2-

-0.906

"As

76.920646

38.8 h

P" (0.6904); y

3/2-

Uses

R

Other radioisotopes of arsenic have half-lives of less than 2 hours.

Astatine Isotopes of astatine with half-lives longer than 10 minutes are given in the main table on page 29.

Barium Nuclide

Atomic mass

Half life /2 4p3/2 4d3/2 4d5/2

186 123 123 50 50

Iridium Electron binding energies /eV N, N„ Nm N,v Nv Nv, Nv,, 0, 0, Om

256

27.5 14.1 14.1

Lanthanum Electron binding energies /eV N, N„ Nm Nw Nv Nw Nv,, 0,

o„ o,„

4s 4pl/2 4p3/2 4d3/2 4d5,2 4f5/2 4f?,2 5s 5p„2 5p3/2

274.7 205.8 196.0 105.3 102.5

4s 4Pl/2 4p3/2 4d5,2 4f*7/2 5s 5p„2 5P3/2

691.1 577.8 495.8 311.9 296.3 63.8 60.8 95.2 63.0 48.0

N, N„ NIU Nw Nv Nv, Nvn 0, On Om

4s 4p„2 4P3/2 4d3/2 4d5/2 4^5/2 4f7/2' 5s 5p„2 5p3/2

319.2 243.3 224.6 120.5 120.5 1.5 1.5 37.5 21.1 21.1

Niobium

-

34.3 19.3 16.8

Electron binding energies /eV N, N„ Nm

4s 4pi/2 4P3/2

56.4 32.6 30.8

Lead

Osmium

Electron binding energies /eV

Electron binding energies /eV

N, N„ Nm N,v Nv Nv, Nv,, 0, On Qn Oiv

ov

4s 4p,,2 4p3/2 4d3,2 4d5,2 4fs/2 4f?/2 5s 5p„2 5p3,2 5d3/2 5d5/2

891.8 761.9 634.5 434.3 412.2 141.7 136.9 147 106.4 83.3 20.7 18.1

N, N„ Nra Nw Nv Nv, Nvn 0, On Om

4s 4pi,2 4P3/2 4d5/2 4f7/2 5s 5p„2 5P3/2

658.2 549.1 470.7 293.1 278.5 53.4 50.7 84 58 44.5

Palladium

Lutetium

Electron binding energies /eV

Electron binding energies /eV

N, N„ N,„

N, N„ Nm Nw Nv Nv, Nv,, 0,

o„

0,u

4s 4Pl/2 4p3/2 4d5/2 4f5/2 4f?/2 5s 5p„2 5p3,2

506.8 412.4 359.2 206.1 196.3 8.9 7.5 57.3 33.6 26.7

Mercury

Iodine N, N„ Nm Nrv Nv

N, N„ N,„

4s 4p,/2 4p3/2

Electron binding energies /eV N, N„ Nm N,v Nv Nv, Nvn 0, 0„ On,

ow

Ov

4s 4p,,2 4p3/2 4d3/2 4d5,2 4^5/2 4f?,2 5s 5p„2 5p3,2 5d3/2 5d5/2

802.2 680.2 576.6 378.2 358.8 104.0 99.9 127 83.1 64.5 9.6 7.8

Electron binding energies /eV N, N„ Nm

4s 4p,/2 4p3/2

63.2 37.6 35.5

87.1 55.7 50.9

Platinum Electron binding energies /eV N, N„ Nm Nw Nv Nv, Nv„ 0,

o„

On,

4s

4d5/2 4f7/2 5s 5pi/2 5p3/2

725.4 609.1 519.4 331.6 314.6 74.5 71.2 101.7 65.3 51.7

Polonium Electron binding energies / eV N, N„ N„, Nw Nv Nv, Nvn

o,

Molybdenum

4s 4p,/2 4P3/2

0„ 0„, On/ Ov

4s

4^5/2 4f?/2 5s 5p„2 5d3/2 5d5/2

995 851 705 500 473 184 184 177 132 104 31 31

Electron binding energies

Praseodymium

Radon

Electron binding energies /eV N, N„ N,u N,v Nv Nv, Nvn 0, o„ Om

4s 4Pl/2 4p3/2

4d3,2 4d5,2 4t*>/2 4fr/2

5s 5Pl/2 5p3/2

Strontium

Electron binding energies /eV

304.5 236.3 217.6 115.1 115.1 2.0 2.0 37.4 22.3 22.3

Promethium

N, N„ N„, Njv Nv Nv, Nvn 0, o„ On, On/ Ov Pi

4s 4pi/2 4p3/2 4d3/2 4d5/2 4^5/2 4f?/2 5s 5Pl/2 5P3/2 5d3/2 5d5/2 6s

1097 929 768 567 541 238 238 214 164 127 48 48 26

Electron binding energies /eV N, N„ N,„ NIV Nv Nw Nvn 0, 0„ 0,1,

4s 4Pl/2 4p3/2 4d3,2 4d5/2 4f5/2 4fy/2 5s 5p„2 5p3/2

-

242 242 120 120 n.a. n.a. n.a. n.a. n.a.

Protactinium

Rhenium 4s 4pi/2 4P3/2 4d3/2 4d5/2 4^5/2 4f?/2 5s 5Pl/2 5P3/2

625.4 518.7 446.8 273.9 260.5 42.9 40.5 83 45.6 34.6

Electron binding energies /eV N, N„ N,„ N|V Nv Nv, Nv,, o, o„ Ojn 0,v Ov p, P.I Pm

4s 4Pi/2 4P3/2 4d3/2 4d5/2 4fs/2 4f7/2 5s 5Pl/2 5P3/2 5d3/2 5d5/2 6s 6pi/2 6P3/2

1387 1224 1007 743 708 371 360 310 232 232 94 94 -

Radium N, N„ N,„ Nrv Nv Nv, Nvu o, o„ Om Ojv Ov p, p„ Pm

4s 4Pl/2 4p3/2 4d3/2 4d5/2 4^5/2 4f?/2 5s 5Pl/2 ^P3/2 5d3/2 5d5/2 6s 6p,/2 6P3/2

1208 1058 879 636 603 299 299 254 200 153 68 68 44 19 19

4s 4Pl/2 4P3/2

38.9 21.6 20.1

Tantalum Electron binding energies / eV N, N„ N„i N,v Nv Nv, Nvn On On,

4s 4Pl/2 4P3/2

4d3/2 4d5/2 4^5/2 4f?/2 5s 5p,/2 ^P3/2

563.4 463.4 400.9 237.9 226.4 23.5 21.6 69.7 42.2 32.7

Technetium Electron binding energies / eV N, N„ N,„

4s 4Pl/2 4P3/2

69.5 42.3 39.9

Tellurium Electron binding energies /eV

Rhodium Electron binding energies /eV N, N„ N,u

4s 4Pl/2 4p3/2

81.4 50.5 47.3

N, N„ Nm NIV Nv

4s 4pl/2 4P3/2

4d3/2 4d5/2

169.4 103.3 103.3 41.9 40.4

Terbium

Rubidium

Electron binding energies /eV Electron binding energies leV N, N„ N,„

4s 4p J/2 4p3/2

30.5 16.3 15.3

Ruthenium Electron binding energies /eV

Electron binding energies /eV

N, N„ Nm

0,

Electron binding energies /eV N, N„ N,„ N,v Nv Nw Nvu 0, On On,

Electron binding energies /eV

N, N„ N,„

4s 4Pl/2 4p3/2

75.0 46.5 43.2

396.0 322.4 284.1 150.5 150.5 7.7 2.4 45.6 28.7 22.6

Electron binding energies /eV

Electron binding energies /eV 4s 4pi/2 4P3/2 4d3/2 4d5/2 4^/2 4^7/2 5s 5Pl/2 5p3/2

4s 4Pl/2 4p3/2 4d3/2 4d5/2 4^5/2 4fy/2 5s 5p„2 5P3/2

Thallium

Samarium N, N„ Nm N,v Nv Nv, Nvn 0, o„ o,„

N, N„ Nm N,v Nv Nv, Nvn 0, 0„ Om

347.2 265.6 247.4 129.0 129.0 5.2 5.2 37.4 21.3 21.3

N, N„ Nm N|V Nv Nv, Nvn o, 0„ o,„ Ojv Ov

4s 4Pl/2

4P3/2 4d3/2 4d5,2 4fs/2 4f?/2 5s 5p,/2 5P3/2 5d3/2 5d5/2

846.2 720.5 609.5 405.7 385.0 122.2 117.8 136 94.6 73.5 14.7 12.5

Silver Electron binding energies / eV N, N„ Nu,

4s 4Pl/2 4p3/2

97.0 63.7 58.3

257

APPENDIX 2

■Hi

1

Thorium

Xenon

Electron binding energies /eV

Electron binding energies /eV

4s 4pi/2 4p3/2

N, Nn N,„ N,v Nv Ny, Nvn

4d3/2 4d5/2 4f5/2 4^7/2

0, o„ 0„,

5s 5p„2 5p3/2 5d3/2

Oiv Ov Pi P,i Pm

5d5/2

6s 6P1/2 6p3/2

1330 1168 966.4 712.1 675.2 342.4 333.1 290 229 182 92.5 85.4 41.4 24.5 16.6

Thulium Electron binding energies / eV N, N„ Nn, Nw Nv Nv, Nvn

4s 4p | /2 4p3/2

0, o„ o,„

5s 5p,/2 5p3/2

4d3i2 4d5/2 4^5/2 4f*7/2

470.9 385.9 332.6 175.5 175.5

4.6 54.7 31.8 25.0

Tin Electron binding energies /eV N, N„ N,„ NIV Nv

4s 4Pl/2 4P3/2 4d3/2

4d5/2

137.1 83.6 83.6 24.9 23.9

Tungsten Electron binding energies /eV N, N„ N,„ Nlv Nv Ny, Nv„ 0, 0„ 0„,

4s 4p,/2 4P3/2 4d3/2 4d5/2 4fs/2 4^7/2 5s 5p„2 5p3/2

594.1 490.4 423.6 255.9 243.5 33.6 31.4 75.6 45.3 36.8

Uranium Electron binding energies /eV N, N„ N,„ N,v Nv Nv, Nvn 0, 0„

o,„ 0,v

ov p, p„ p,„ 258

4s 4p,,2 4p,,/2 4d3/2 4d5,2 4fs/2 4f7,2 5s 5p„2 ' Sp3,2 5d3/2 5d5/2 6s 6p„2 6P3/2

1439 1271 1043 778.3 736.2 388.2 377.4 321 257 192 102.8 94.2 43.9 26.8 16.8

N, N„ N„i N,v Nv Nw Nvn

4s 4p„2 4P3/2

0, 0„

0,1!

4d5,2

213.2 146.7 145.5 69.5 67.5

4fs/2 4f*7/2

-

5s 5p„2 5p3,2

23.3 13.4 12.1

4d3/2

Ytterbium Electron binding energies /eV N, N„ Nn, N,v Nv Nw Nv„

4s 4pi/2 4p3,2

0, o„ 0,„

5s 5p,/2 5p3,2

4d5,2 4fs/2 4f?/2

480.5 388.7 339.7 191.2 182.4 2.5 1.3 52.0 30.3 24.1

Yttrium Electron binding energies /eV N, Nn Nm

4s 4p,,2 4p3/2

43.8 24.4 23.1

Zirconium Electron binding energies /eV N, N„ N„,

4s 4P3/2

50.6 28.5 27.1

APPENDIX 3

Minerals additional data This appendix contains additional data to the minerals tables in the Geological Data sections of some of the elements

Aluminium Mineral

Formula

Density

Hardness

Crystal appearance

Andalusite Corundum Sillimanite Topaz

Al2Si05 A1203 Al2Si05 Al2Si04(F,0H)2

3.14 4.0 3.25 3.5

6.5-7.5 9 6.5-7.5 9

orth., trans., pink, red etc. rhom., vit. colourless/brown (gem) orth., trans., colourless, white, etc. orth., trans., colourless, yellow, etc.

This does not complete the list, there are many other aluminium silicates than those given here. See Key for reference works to minerals.

Calcium Mineral

Formula

Density

Hardness

Crystal appearance

Gypsum Shortite Vaterite

CaS04.2H20 Na2Ca2(C03)3 CaC03

2.317 2.63 2.54

2 3 n.a.

mon., vit. colourless orth., vit. colourless hex., translucent/colourless

There are many other minerals in which calcium is present

Copper Mineral

Formula

Density

Hardness

Crystal appearance

Chrysocolla Covellite Cuprite Dioptase* Enargite Malachite Rosasite Tetrahedrite

(Cu,Al)2H2Si205(OH)4 Cu2S Cu20 CuSi03.H20 Cu3AsS4 Cu2(COs)(OH)2 (Cu,Zn)2(C03)(OH)2 (Cu,Fe)12Sb4S13

2 4.7 6.14 3.3 4.45 4.05 4.1 4.97

2-4 1.5-2 3.5-4 5 3 3.5-4 4.5 3-4.5

orth., vit. earthy green/blue hex., sub-metallic blue cub., adamantine sub-metallic red rhom., vit. green orth., metallic grey-black mon., vit./silky earthy green mon., green-blue cub., metalic grey/black

* Used in jewelry

Magnesium Mineral

Formula

Density

Hardness

Crystal appearance

Epsomite Kiersite Magnesite Pyrope Spinel

MgSO„.7H20 MgS04.H20 MgC03 Mg3Al2(Si04)3 MgAl204

1.677 2.571 3.00 3.51 3.55

2-2.5 3.5 4 6.5-7.5 7.5-8

orth., vit./silky/earthy colourless mon., vit., colourless-white rhom., vit. colourless compact cub., vit./resinous deep red cub., vit. pink (gem)

Silicon Mineral

Formula

Density

Hardness

Crystal appearance

Muscovite* Talc Tremolite*

KAl2(Si3Al)O10(OH)2 Mg3Si4O10(OH)2 Ca2Mg5Si8022(0H)2

2.8 2.7 3.0

2.5-3

mon., trans. colourless-pale green trie.,trans./colourless-white mon., vit. colourless-grey

1

5-6

*mica; 'asbestos-like mineral Other groups of sEicates include the following: Potassium magnesium silicates: Biotite; Chrysotile; Phlogopite Calcium aluminium silicates: Margarite; Montmorillonite; Phrenite Magnesium aluminium silicates: Clinochlore; Vermiculite Sodium potassium calcium aluminium silicates: Albite; Analcime; Apophyllite; Kaolinite; Laumonite; Microcline; Muscovite; Nepheline; Oligoclase; Phlogopite; Pyrophyllite; Sodalite.

259

The periodic table

O n the inside front cover of this book you will find a periodic table of all the ele¬ ments that have been reported up to 1995. The periodic table has been around for so long, adorning classrooms, lecture halls and chemical laboratories, that you might imagine this is the only possible version. It may come as a surprise to learn that more than 600 periodic tables have been published in the past 125 years. According to E. G. Mazurs’ book, Graphic representations of the periodic system dur¬ ing one hundred years, there are about 150 basically different formats of the table, but hundreds of variations of these. One of the first was drawn up by the Russian chemist Dimitri Mendeleyev on 1 March 1869. He is righfiy seen as the discoverer of the periodic table because he based his on stricdy scientific principles. Chemists had been groping towards a classification of the elements before this date, as they found more and more of them, and some came close to discovering the periodic table itself, as we shall see. Since the time of Mendeleyev, other chemists have redesigned his periodic table many times, sometimes in response to new elements being discovered or made artificially, sometimes in response to advances in our knowledge about the nature of atoms. Looking back from our vantage point in time, we might perhaps see it as inevitable that a periodic table would be devised sooner or later. Once chemists knew about the subatomic particles which make up atoms, it would have been inevitable. The number of positive protons in the nucleus of an atom, the so-called atomic number, determines the element: hydrogen has one proton, helium two, lithium three, beryllium four, boron five, and so on up to element 100 (fermium) and beyond. The electrons in the orbits which surround the nucleus, and especially those in the outermost orbit are responsible for the chemistry of the element, and when the outer electron configuration is the same, then those elements should resemble one another. This explains the periodic repetition of chemical properties and behaviour that is observed in the groups of the periodic table. The remarkable achievement of Mendeleyev was that he produced his periodic table 27 years before foseph Thomson (1856-1940) discovered the electron in 1897,1 and 42 years before Ernest Rutherford (1871-1937) discovered the positively charged atomic nucleus in 1911. The neutrons in the nucleus are also important— they are the key to explaining anomalous atomic weights and isotopes—and were discovered in 1930 by lames Chadwick (1891-1974) who earned a Nobel prize in 1935 for his work. Yet when Mendeleyev heard of the discovery of electrons in 1897, he rejected the idea that they came from atoms. He believed that atoms were indivisible. Indeed he predicted that the electron would disappear from science in the way that phlogis¬ ton had. This may strike us as mildly eccentric now, but in those days some eminent scientists were still not convinced of the existence of atoms, never mind electrons! One such sceptic was the electrochemist Wilhelm Ostwald (1853-1932).

A brief history of atoms and elements The idea of atoms can be traced back to the ancient Greek philosophers who were the first to argue that matter must be composed of them. One argument they used to prove this went as follows: consider what happens when you slice horizontally through a cone. If matter is continuous then both faces of the slice must be exacdy the same size, but since they are part of a cone then they must be different. The lower face must be larger, but that can only be so if we have sliced between two 1 Joseph John Thomson won the Nobel prize for physics in 1906 for this work. Curiously the name for the electron preceded its discovery. Michael Faraday first suggested that there were particles of electricity in 1834, and the name electrine was suggested by George J. Stoney for the unit of electrical charge in 1874. He changed this to electron in 1891. 261

THE PERIODIC TABLE planes of atoms. The chief atomists were Leucippus and his pupil, Democritus, and their ideas were developed by Epicurus (341-270 bc). We know of their theories because of the book De rerum natura (On Natural Things) which was published around 55 bc by the Roman poet Lucretius, and is still in print. Another philosophical debate concerned the idea of elements. To begin with the Greek philosophers thought in terms of the element and debated what it might be. For example, Heraclitus thought it was water, while others suggested air, or fire. Empedocles (ca. 400 bc) proposed there were four elements, an idea taken up by the great Aristotle (384-322 bc) who named them as earth, air, fire, and water.2 This seemed very reasonable and was supported by commonsense observation, such as what happens when a stick burns in a fire. It can be seen to break down into the four elements: flames, steam, gases, and ash. For 2,000 years Aristotle’s ideas were accepted in Europe, almost without ques¬ tion, until the dawn of modern science in the seventeenth century. In the eigh¬ teenth century the concept of chemical elements emerged and it became clear that ten of these had indeed been known for thousands of years, but not recognized as such, see Table 1. Table 1 The chemical elements known to the Ancients Carbon as charcoal came with the discovery of fire. Sulfur was to be found near volcanoes. Copper was the first metal to be worked, around 5000 bc. Gold and silver objects were first produced about 3000

bc.

Iron smelting led to the Iron Age which began around 2500 bc. Tin was used earlier to forge bronze, an alloy of copper that was much stronger, but the element itself was not smelted as such until around 2100 bc. Mercury was reported about 1500 bc. This forms when the ore cinnabar (HgS) is heated, and it also occurs naturally in cinnabar deposits. Lead appeared around 1000 bc and was extensively mined. It became the most important metal in the Roman Empire. Antimony objects date from around 1600

bc

although this metal was not much used.

The Dark Ages in Europe traditionally began with the sack of Rome in ad 410. Science and technology declined, later to be revived by the Arabs and spread out with them during their years of expansion. Alchemy had it adherents and some ele¬ ments were discovered during this period. Arsenic appears to have been isolated by the German alchemist, Magnus, in the middle of the thirteenth century; bismuth appeared towards the end of the fifteenth century; phosphorus was made by Hennig Brandt of Hamburg in 1669. This last element had amazing properties: it burst into flames spontaneously when exposed to air and it glowed in the dark. The discovery of phosphorus is seen as a turning point between alchemy and chemistry. By 1700 there were 15 known elements, although these were still not recognized as chemical elements. To those above can be added zinc, which was smelted as such in the fifteenth century, and platinum, which was brought back to Europe from the New World where it was regarded it as a superior form of silver because it did not tarnish. However, the eighteenth century saw the emergence of chemistry in Europe and the discovery of several new metals: cobalt (1735), nickel (1751), magnesium (1755), manganese (1774), chromium (1780), molybdenum (1781), tellurium (1783), tung¬ sten (1783), zirconium (1789), uranium (1789) and a few gases: hydrogen (1766), nitrogen (1772), oxygen (c.1772), and chlorine (1774). It was left to the great French chemist, Antoine Laurent de Lavoisier (1743-94),3 2 In China scientific philosophy was based on there being five elements: air, earth, fire, water, and wood. 3 Lavoisier was executed on 8 May 1794 during the Reign of Terror following the French Revolution of 1789. Athough officially charged with adulterating tobacco, it was his links with the tax gathering organization, the Fermier Generate, that brought him to the guillotine. After his death his widow, Marie-Anne, continued to publish his work. 262

THE PERIODIC TABLE to bring order to the fledgling science, which he did with his remarkable book Traite elementaire de chemie in 1789. In this he defined a chemical element as something which could not be further broken down (decomposed) and he listed 33 substances that came within the terms of his definition. He classified them into four categories: gases, non-metals, metals, and earths (see Table 2). Under gases he included heat and light. Another of Lavoisier’s brilliant contributions to chemistry was to advo¬ cate that chemicals should be named after the elements of which they were com¬ posed. This de-mystified the language of chemistry of its alchemical names, and the result was that chemicals like ‘butter of antimony’ became antimony chloride, and ‘lunar caustic’ became silver nitrate. Table 2 Lavoisier’s elements

Gases

Non-metals

Metals

Earths'

[Light] [Heat] Oxygen Nitrogen Hydrogen

Sulfur Phosphorus Carbon Chloride* Fluoride* Borate*

Antimony Mercury Arsenic Molybdenum Bismuth Nickel Cobalt Pladnum Copper Silver Gold Tin Iron Tungsten Lead Zinc Manganese

Lime Magnesia Barytes Alumina Silica

* Lavoisier called these radicals, because he knew that although they were elements, they were always accompanied by another element. * These are the inert oxides of the elements calcium, magnesium, barium, aluminium and silicon, which in Lavoisier’s time could not be reduced to simpler substances.

A milestone in the development of chemistry came with the discovery of oxygen, the gas given off when calx of mercury (mercuric oxide) was heated. The discovery is attributed to Joseph Priestley (1733-1804) in 1774, but oxygen had already been iso¬ lated by Carl Wilhelm Scheele (1742-86) two years earlier, although not reported until 1777. Oxygen delivered the greatest blow to Aristotle’s four elements when in 1781 Joseph Priestly (1733-1804) demonstrated that water was not an element because it could be formed from hydrogen and oxygen. Another intellectual revolution was initiated by John Dalton (1766-1844) a sci¬ ence teacher living in Manchester, England. He pondered on the atomic nature of matter and realized that the Law of Fixed Proportions, which recognized that ele¬ ments combined with one another in fixed ratios of weights, could be explained if they were composed of atoms. In 1803 Dalton presented a paper to the Manchester Literary and Philosophical Society entitled ‘On the absorption of gases by water and other liquids’. In this he attempted to explain the different solubilities of gases by comparing the relative weights of them. This led him to propose a scale of atomic weights and when he published his talk in the newly launched Proceedings of the Society in 1805, he explored the idea further and appended a list of 20 elements with their atomic weights, and suggested atomic symbols—see Fig. 1. At a stroke Dalton’s theory not only proposed the existence of atoms, but suggested that atoms of each element had individual weights and that these could be calculated relative to one another. By 1810, chemistry was an established science, producing remarkable discover¬ ies almost every year, not least of which was a constant supply of new elements. In the years between the publication of Lavoisier’s Traite and Dalton’s talk, another ten or so had been discovered: titanium (1791), yttrium (1794), beryllium (1797), vanadium (1801), niobium (1801), tantalum (1802), rhodium (1803), palladium (1803), osmium (1803), iridium (1803), and cerium (1803). This pace was to contin¬ ue, especially when Humphry Davy discovered that Lavoisier’s ‘earths’ could be decomposed by electrolysis into new elements. This led to the isolation of potassi¬ um (1807), sodium (1807), calcium (1808), and barium (1808). Strontium was isolat¬ ed by Crawford in the same year. 263

THE PERIODIC TABLE

ELEMENTS

o (D • O ® © © ©

(III)

Wm

Hydrogen

T

-A tote

f

Carbon

Oxygen Phospkoru Sulphur Magnesia Lime Soda Potash

/T\

O O

S tmi» ban

*

Barytes

68

^

® Iron J'0 l © ZiilC j6 © Copper s6 n © Lead SO to © Silver yo © Gold yo © Platina igo 4*\ © Mercury 16/ $

24

1%

Fig. 1 Daltons table of elements

Boron was also discovered in 1808, then came iodine in 1811. The year 1817 was particularly fruitful with thorium, lithium, selenium, and cadmium being announced. By now the chemical similarity of groups of elements began to be com¬ mented on. In 1829 Johann Wolfgang Dobereiner (1780-1849) announced his Law of Triads, in which he noted that many elements came in groups of three (‘triads’), and of which the weight of the middle element was the average of the lighter and heavier members. Lithium/sodium/potassium were one such triad and others were chlorine/bromine4/iodine and sulfur/selenium/tellurium. By the time Leopold Gmelin published the first edition of his compilation of essential chemical data, Handbuch der Chemie, in 1843 he noted there were ten triads, three tetrads, and even a pentad: nitrogen/phosphorus/arsenic/antimony/bismuth. Today we recognize this pentad as group 15 of the modern periodic table. Occasionally there were curious insights into the underlying nature of matter— and one that was well in advance of its time was the hypothesis put forward by Prout in 1815. He proposed that all the elements were multiples of the atomic weight of hydrogen, which is the lightest. If this is taken as 1 then it explained why all the other elements had weights that were whole numbers.5 Although absolute atomic weights were not known as such, it was possible to compare the weights of the elements to one another, and this was done with respect to oxygen which forms compounds with almost all of them. Oxygen was taken to be 8, which followed from a comparison with hydrogen, and the 1:8 ratio of these ele¬ ments in water. At the time the composition of water was assumed to be HO, not H20. In fact the true formula could have been deduced as early as 1800 when William Nicholson and Anthony Carlisle electrolysed water and showed it decomposed into two volumes of hydrogen and one of oxygen. The significance of this was not real¬ ized, even though in 1811 Amadeo Avagadro (1776-1856) suggested that equal vol¬ umes of gases contained equal numbers of particles (molecules). Eventually it was deduced that the formula for water was H20, and the weight of oxygen was corre¬ spondingly adjusted to 16. Most elements had relative weights that were whole numbers, and this contin¬ ued to be true as more were discovered. Prout’s hypothesis was tantalizingly almost correct in assuming that hydrogen was the element of elements. In a way he had 4 Bromine had been discovered in 1826. 5 Not quite all, a notable exception being chlorine (35.5). 264

THE PERIODIC TABLE been right. Most hydrogen atoms consist of a single proton, and it is the number of protons which determines the nature of all the elements. The nucleus of an atom is where 99.98 per cent of its weight resides. Because this is composed of protons and neutrons which have exactly the same mass, and because most elements have one dominant isotope, then it is not surprising that their weights will tend to whole numbers. A glance at the periodic table on the inside cover will show that this is so, revealing that most elements have atomic weights that fall within the limits ± 0.1 of an integer, with few having fractional numbers. Apart from chlorine, already men¬ tioned, nickel (58.7) copper (63.5) and zinc (65.4) are notable exceptions. From 1830 to 1860 only three new elements appeared: lanthanum (1839), erbium (1842), and terbium (1843). These metals were later to yield other metals because they were part of the group known as the rare earths, all of which have very similar properties, making them difficult to separate from one another. The next era of element discovery came with the atomic spectroscope, which revealed that each element had a characteristic fingerprint pattern of lines in the visible spectrum. Merely submitting a new mineral to this technique immediately showed that a new element was present if new lines appeared in the spectrum. As a result rubidium, caesium, thallium and indium were announced in the years 1860-3. The total of known elements was now in excess of 60 and chemists were begin¬ ning to ask whether there was a limit to the number. To answer this question required a theory that could explain the known and predict the unknown. The ‘tri¬ ads’, ‘tetrads’ and ‘pentads’, were governed by regular increases in relative weight.6 Clearly chemists might use this universal property to rank all the elements, if only they could talk in terms of relative atomic weights. The Italian chemist Stanislao Cannizzaro (1826-1910) was to be instrumental in bringing this about.

Atomic weights and the first periodic tables In 1858 Cannizzaro published his ‘Outline of a course of chemical philosophy’ in which he showed how atomic weights could be deduced if Avogadro’s Law was accepted, and he presented a paper at the First International Chemical Congress which was held at Karlsruhe in 1860. Cannizzaro argued that the law led direcdy to the atomic weights of gaseous elements, and thence to other elements. A given vol¬ ume of oxygen gas is 16 times heavier than the same volume of hydrogen, so if the latter has an atomic weight of 1.0 then oxygen must be 16.0.7 Cannizzaro’s ideas were quickly accepted and copies of his table of atomic weights were eagerly sought by conference members. One fell into the hands of a young Russian student, Dimitri Mendeleyev, who was then engaged in postgraduate research in Germany. The table of atomic weights triggered a new debate about the elements. The first attempt to arrange all of them in a regular pattern was made in 1862 by a French geologist Alexandre Emile Becuyer de Chancourtois (1820-86). He wrote down the elements in order of increasing atomic weight on a piece of tape and then wound this spiral-like around a cylinder—Fig. 2. The cylinder surface was divided into 16 parts, based on the atomic weight of oxygen. Chancourtois noted that certain triads came together down the cylinder, such as the alkali metals, lithium, sodium and potassium whose atomic weights are 7,23 (7+16), and 39 (23 + 16). This coincidence was also true of the tetrad oxygen/sulfur/selenium/tellurium. He called his model the Vis Tellurique (Telluric Screw) and published it in 1862. He concluded: ‘the properties of substances are the properties of numbers.’ His paper had little impact among chemists, but this might have been because some of the alignments did not make chemical sense; for example one of his groups consisted of boron, alumini¬ um, nickel, arsenic, lanthanum and palladium. What Chancourtois had discovered was the periodic nature of the elements. In other words, elements with the same properties occurred at regular periodic inter6 Rubidium and caesium extended the lithium/sodium/potassium triad to a pentad. 7 This also proved that the correct chemical formula for water was H20, not HO. 265

THE PERIODIC TABLE

Fig. 2 A table of atomic weights by Alexandre Emile Becuyer de Chancourtois vals, in this case when the atomic weights differed by 16, as with the alkali metals, or if they were multiples of 16, or nearly so, such as we find with oxygen = 16, sulfur = 32, selenium = 79 (5 x 16 = 80) and tellurium = 128 (8 x 16). Clearly there appeared to be an underlying numerical rhythm to the elements, even though we now know that it is more by luck than by logic that the elements of the oxygen-tellurium tetrad are such close multiples of 16.® Another attempt to classify the elements was made by an Englishman, 27-year old John Alexander Reina Newlands (1837-98). He wrote articles for the London weekly Chemical News, in one of which (1865, volume 12, page 83) he arranged 56 elements into groups and noted that there seemed to be a repetition of properties with every eighth element. In 1864 he had read a paper entitled ‘The law of octaves’ to a meeting of the London Chemical Society, and the title was chosen by analogy with octaves in music. This was an ill-judged choice, and it is said that one member of his audience8 9 mockingly asked Newlands whether he had ever thought of arrang¬ ing the elements alphabetically instead. The society’s journal refused to publish his paper. However, the Royal Society of London award him the Davy Medal in 1887 in belated recognition of his achievement. 8 Although polonium, the next element in this group, was not to be discovered for another 36 years, it too would have fallen into line with its partners in the Telluric Screw because its most stable isotope has an atomic weight of 209 (13x16 = 208). Marie Curie isolated this radioactive element in 1898. 9 Believed to be a Professor Carey Foster. 266

THE PERIODIC TABLE What was curious about Newlands approach was that, although he placed ele¬ ments in groups that we would now recognize as part of the periodic table, he was clearly not aware of any underlying imperative for so doing. For example, he noticed that silicon and tin should be part of a triad, but he left no vacant place in the table for the missing element between them. Nor had he any qualms about putting two elements together in some of the boxes in his table. William Odling, successor to Michael Faraday at the Royal Institution in London, was another chemist to speculate about relationships among the ele¬ ments, and he published a paper entitled: ‘On the proportional numbers of the ele¬ ments’ in the first volume of the Quarterly Journal of Science (1864, page 642). His arrangement of the elements came surprisingly close to that of Mendeleyev’s first attempt, and he left gaps where there were missing elements. In fact he even left gaps that were later to be filled by helium and neon, although he thought these would be lighter elements of a pentad which expanded the triad of zinc/cadmium/mercury. He also suggested, wrongly, that lithium and thallium were the top and bottom of another pentad. Another scientist to come near to discovering the periodic table was the German, Julius Lothar Meyer (1830-95). He published a table of 49 elements with their valencies in 1864, and he drew a graph of atomic volumes versus atomic weight in 1868 which shows a periodic rise and fall, and from which he deduced a periodic table.10 He passed this paper to a colleague, Professor Remele, for his com¬ ments. Unfortunately these were slow in coming, and before he could submit it for publication Mendeleyev’s definitive paper had appeared.

Dimitri Mendeleyev The first genuine periodic table of the elements was produced by a relatively unknown Russian professor of chemistry, Dimitri Ivanovich Mendeleyev (1834-1907). He was born in Tobolsk in western Siberia on 8 February 1834, the fourteenth child of a local school master. However, it was his mother, Maria, who raised the children after her husband became blind. She came from a family with interests in glassworks and paper mills and these she ran while struggling to edu¬ cate her favourite son, Dimitri. Eventually she took him to Moscow, but failed to secure him a place at the university there, so instead went to St Petersburg, where he was allowed to enroll at the Central Pedagogic Institute to study physics and mathematics. He graduated with a gold medal for excellence in scholarship, and in 1859 went to study for his doctorate, first to Paris, working under Henri-Victor Regnault, and then to Heidelberg, supervised by Robert Bunsen. In 1861 he returned to St Petersburg, that great city on the Baltic which prided itself on its European architecture and culture. In the 1860s it was at the leading edge of reform as Russia began the painful road from feudalism to a modern indus¬ trial society. A liberated outlook promoted education, science and the arts, in ways that were well ahead of their time. For example women were encouraged to become educated and take up professions. In this atmosphere of reform chemistry flour¬ ished. Even today we are reminded of this period when we use the Markovnikoff rule to predict the way an olefin will react, or listen to the music of Borodin, a chemist who is better known as the composer of symphonies.11 But its most endur¬ ing chemical monument is the periodic table. Mendeleyev became a professor of chemistry in 1867, and began to write his textbook The principles of chemistry, which was to run into many editions and be translated into French, German, and English. It was while preparing the second vol¬ ume that he made his momentous discovery. In trying to find a format for the chap¬ ters of the book, he grouped the elements according to their valencies. 10 Atomic volume is defined as atomic weight divided by density. It is the volume occupied by a mole (6.022 x 102 ! atoms) of an element—see physical data section. 11 The best known of which is the opera Prince Igor on which the musical Scheherazade is based. 267

THE PERIODIC TABLE On a winter’s day in 1869 the breakthrough happened.12 Mendeleyev’s move¬ ments that day are well documented. He had planned to visit a cheese factory in the morning but this was called off, and instead he worked on his book. He wrote the name of each element on individual pieces of card, together with its atomic weight, a few physical properties and the formulae of any hydrides and oxides it formed. These cards he arranged in sets of increasing atomic weight with elements having the same valency, as shown by their hydrides or oxides, in the same row (see Fig. 3.) He produced one arrangement that particularly impressed him and wrote it down on to the back of an envelope. This can be considered his first periodic table, and the envelope still exists.13 After his midday meal he took a nap, and on waking he decided that a vertical arrangement of groups was a better way of depicting the periodic table. This event was to give rise to the romantic notion that the periodic table came to Mendeleyev in a dream. In any case he redrew his table and this has remained the standard format to this day. What makes Mendeleyev’s table so important was that he realized that he had stumbled on an underlying order to the elements and this gave him the confidence to make a few predictions, some of which were soon to be proved right, and some of which were later to be proved wrong. If Mendeleyev’s periodic table were correct, it should show gaps where ele¬ ments, yet unknown, should come. Below aluminium and silicon were such vacant spaces. These elements he named eka-aluminium and eka-silicon. He predicted their atomic weights, physical properties such as melting points and densities, and said what the chemical composition of their oxides and other compounds would be. In another part of the table Mendeleyev was able to resolve a long-standing dis¬ pute over the formula for the oxide of beryllium. Some claimed it was Be203 while others said BeO. The former was inconsistent with beryllium’s position in group two of his table, so Mendeleyev rightly said that the formula must be BeO. He made another prediction with equal certainty, but in this Mendeleyev was wrong. He said that the atomic weight of tellurium or iodine must be incorrect. To the nearest whole numbers these were 128 (Te) and 127 (I). Clearly a periodic table

H-l Be—9,4 B-ll C—12 N-14

0-16 F—19 Li —7

Na— 23

Ti —50 V — 51 Cr —52 Mu —55 Fe —56 Ni -Co-59 Cii —63,4 Mg-24 Zn —65,t Al —27,4 ?-6 8 Si-28 7=70 P-31 As—75 S —32 Se—79,4 Cl —35,» K —39 Ca —40 ?—45 ?Er—56 ?Yt—60 ?lu-75,a

Br=30 Rh-85,4 Sr—87,a Ce-92 La-94 Di-95

Zr—90 Nb-94

? —1819S, Au=l99.



_

Bi = 208

Pbx*107 Tb = 28l

J=127 —

— W

Kq =104, Rh = 104, Pd=io«, A*=uoa.

— *=100

Te= 125



Fo = 66, Co = 59. Ni = 59, Cm 63.

Br = 80

.So = 78

-



Cl = 35,5 Mu = 55

Mo =96

Sb= 122

So = 118



?Er*= 178

A* = 75

— = 72

?C« = 140

7Di= 138

Ba=l37

Cr=52

V=61

Zr = 90

K=I9 b = 32

K = 31

Si= 28 Ti=48

?Yl=88

CJ = nV

(Ag=108) C« = 135

9

— = 44

Zn = 65

(Cm 63)

5

A1 = 27,3

0=16

N= 14

C = 12

B = I1

Mg = U



11= 240

~

Fig. 4 Mendeleyev’s periodic table as published in Zeitschrift fur Chemie

15 He did not recognize erbium and terbium as part of a missing group because in his first table he assumed their atomic weights were 56 and 60, which are a third of their real values of 167 and 173. 16 This was 6 March 1869 by the Julian calendar. 270

THE PERIODIC TABLE B. Vanadium was in VA and phosphorus in VB. In group IA, for example, there were the so-called alkali metals, lithium, sodium, potassium, rubidium and caesium and in group IB were copper, silver and gold. The same pattern was repeated in the other columns with the exception of group VIII which contained metals which were very similar and which occurred in three sets of three. These were iron/cobalt/ nickel, ruthenium/rhodium/palladium, and osmium/iridium/platinum. Examination of Fig. 4 reveals other problems that Mendeleyev wrestled with. In group III he has ?Yt, ?Di and ?Er referring to the elements yttrium, didymium, and erbium, but questioning whether these were correctly placed. They were, in terms of their chemical preference for oxidation state III, but were misplaced because they are part of the group of 14 rare earths. In any case didymium turned out not to be an element but was a mixture of two rare earth elements praseodymium and neodymium. Mendeleyev’s group VIIA has gaps below manganese, and understandably so, because the heavier members of this group, i.e. technetium, rhenium and bohrium, are either radioactive or rare. All the isotopes of technetium are radioactive and none is stable enough to have existed throughout geological time. Some tech¬ netium isotopes have half-lives of several million of years, but this still means that they have long since vanished from the Earth’s crust. Technetium was finally made by Emilio Segre in 1937 by bombarding molybdenum with heavy hydrogen nuclei. Below technetium comes rhenium, one of the rarest elements on the planet, and one which was not isolated until 1925, and below rhenium is bohrium of which only a few atoms have ever been made.

Isotopes The American Theodore W. Richards (1868-1928) won the Nobel Prize in chemistry in 1914 for his accurate work in measuring the atomic weights of elements. The year previous to winning the award he had uncovered something rather disturbing about the atomic weight of lead. It varied according to where the lead ore was mined. Admittedly the variations were small, but they could not be ignored, and they proved that lead must be composed of atoms with different masses.17 This finding undermined the concept of fixed atomic weights, which was one of the pil¬ lars on which the periodic table rested. Yet the periodic table persisted, and the reason was that the chemical behaviour of lead was not affected by its atomic weight. We now know that atoms of the same element can vary in weight because there are different isotopes. These have the same number of protons in the nucleus but differing numbers of neutrons. The word isotope was coined by Frederick Soddy (1877-1956), and his work in this area was recognized with a Nobel Prize in 1921. His theory explained why tel¬ lurium (element 52, atomic weight 127.6) could be heavier than iodine (element 53, atomic weight 126.9). Tellurium has eight isotopes of which the heavier ones are 129Te comprising 32 per cent and 130Te 34 per cent. Iodine, one the other hand, has only one isotope, 127I. It is not surprising, therefore, that the atomic weight of tellurium should be higher than that of iodine. Today we know of other pairs of adjacent atoms in the periodic table where the atom with the larger atomic number has the smaller atomic weight. They are: •

argon (atomic number 18; atomic weight 39.948) /potassium (19; 39.098)



cobalt (27; 58.933) /nickel (28; 58.69)



thorium (90; 232.038) /protactinium (91; 231.036)



uranium (92; 238.029)/neptunium (93;237.048)

We also know that isotopes can have slight differences in chemical behaviour, and this is most marked with hydrogen. We can see by comparing the properties of ord¬ inary water with those of so-called ‘heavy water’ in which ‘H, the common isotope, 17 Lead varies because it is produced in Nature as the end-product of the radioactive decay of other elements, and these produce different isotopes of lead. 271

THE PERIODIC TABLE has been replaced by 2H, often referred to as deuterium. For example, the melting points are 273.15 and 276.96 K, the boiling points are 373.15 and 374.57 K, and the densities (at 300 K) are 997 and 1104 kg nr3 respectively. Even with a heavy element like uranium the isotopic composition can lead to detectable differences in behaviour, and this was essential to separating the two isotopes of uranium needed for nuclear weapons and nuclear fuel. In this case the isotopic difference affected the rate at which the vapour of uranium hexafluoride, UF6, diffused through a porous barrier. Although 235UF6 is only 0.84 per cent lighter than 238UF6, this is enough to cause the former to diffuse at a measurably faster rate than the latter. Today isotopes play an important part in the study of chemistry, and especially in the analysis of materials and the monitoring of chemical reactions. Important isotopes are indicated in the nuclear data sections of this book. The discovery of isotopes highlighted another problem regarding atomic weights. It was no longer good enough to measure all atomic weights relative to oxy¬ gen, taken to be exacdy 16.0000 because this did not reflect the isotopic composi¬ tion which is 99.75 per cent 160,0.05 per cent 170 and 0.20 per cent 180. Physicists redefined their scale of atomic weights basing them on the isotope 160 taken as exactly 16.0000. This then meant that the atomic weight of naturally occurring oxy¬ gen was 16.0044. Chemists clung to the older scale of atomic weights for many years, but the two scales were brought into line in 1961 when it was agreed to re-base atomic weights on 12C which was defined as 12.0000. This did not change the physicists atomic weight tables and chemists suffered only a 0.033 per cent decrease in the values they used, not enough to cause serious inconvenience.

A multiplicity of periodic tables Within two years of Mendeleyev’s table appearing, other chemists were proposing alternative versions and these have continued to appear year after year. Often they repeat arrangements that have already been proposed. Most tables are two dimen¬ sional representations although there have been several three dimensional versions in the shapes of cylinders, pyramids, spirals and even trees. While these make excel¬ lent displays for museums and chemistry departments, they lack the convenience of a flat format. Computer generated versions offer exciting interactive possibilities and we can expect these to use explorative shapes as teaching aids. Basically there have been two approaches to devising a periodic table: the first lists all the elements in a continuous line, rather like the numbers on a tape mea¬ sure, and this is then looped in such a way that like elements come together. The second version chops the tape into segments and stacks these in rows, again bring¬ ing like elements together. The former approach is what Chancourtois used in 1862, and what many others have done since. The most whimsical one of this type is that produced in Russia by Romanoff in 1934 to celebrate the centenary of Mendeleyev’s birth (see Fig 5). Circular versions of the continuous type of table have also been proposed, but despite their elegance and the tantalizing analogy with electrons in shells around a nucleus (see Fig. 6) they all suffer the drawback of being difficult to read and of abstracting the information they contain. This is because they tend to crowd together the more important elements at their centre while giving the less impor¬ tant elements more room at the periphery.

Noble gases The preferred way of arranging the elements is still the matrix format that Mendeleyev used, but now there is more purpose to it. The modern table denotes each row as the filling of an electron shell, which finally results in a noble gas element when the shell is full. These noble gases have a special place in the development of the periodic table. These were discovered in the 1890s when Lord Rayleigh (1842-1919), William Ramsay (1852-1916), and Morris Travers (18721961) isolated them at University College, London. They had actually been discov272

THE PERIODIC TABLE o

uo

Fig. 5 A whimsical periodic table produced in Russia by Romanoff in 1934

Fig. 6 A circular periodic table

273

THE PERIODIC TABLE ered, but not recognized, in 1766 by Henry Cavendish (1713-1810) at his laboratory in Clapham, South London. He took a mixture of oxygen and air, repeatedly passed electric sparks through it, and absorbed the gases that were formed. He found that not all the air could be oxidized and reported that there remained a residual 1 per cent. This gas we now know was mainly argon with small amounts of the other noble gases. The lightest noble gas, helium, was reported the year before Mendeleyev pro¬ duced his table, by two astronomers, Pierre Janssen (1824-1907) and Norman Lockyer (1836-1920). In 1868 they detected it in the spectrum of light from the sun. They called the new element helium (from the Greek word helios) but it was gener¬ ally assumed that it would not be found on Earth. The separation of the noble gases began with Lord Rayleigh’s researches into the atomic weights of gases. He found that the atomic weight of oxygen was always the same no matter how it was made, but that of nitrogen differed slightly. The nitrogen extracted from air had a density of 1.257 grams per litre, whereas that obtained by decomposing ammonia had a density of 1.251. Together with Ramsay he investi¬ gated the discrepancy, by examining atmospheric nitrogen to see if it contained another component. Like Cavendish, they discovered it contained about 1 per cent of another gas and when they examined the atomic spectrum of this they found lines that could only be explained by a new element. They reported their discovery in 1894 and named the element argon. Because of his knowledge of the periodic table, Ramsay realized that this new gas would not be alone, but would be part of a group. Helium gas was found a few months later, when Ramsay’s attention was drawn to a report by the US geochemist William F. Hillebrand, that when uranium ores were heated, an inert gas was given off. Hillebrand thought this might be nitrogen. Ramsay, with the help of Travers, repeated the experiment, collected the gas and found it had a yellow line in its spectrum which was identical with one discovered discovered 30 years earlier in the spectrum of the sun. Having measured the atomic weights of helium (4) and argon (40) Ramsay was able to deduce that there would be another gaseous element of atomic number about 20, and others heavier than argon with atomic weights around 82 and 132. These would fill gaps in the list of atomic weights between bromine (80) and rubidi¬ um (85), and between iodine (127) and caesium (133). The missing gases were likely to be found in the atmosphere as well, so Ramsay and Travers, careful distilled liq¬ uid air. This had become available in sizeable quantities following the development of a special refrigeration technique, called regenerative cooling. By 1899 they had extracted the missing three gases: neon (atomic weight 20), krypton (84) and xenon (131), naming them after the Greek words neon (new), kryptos (hidden), and xenos (stranger). The heaviest member of the group is radio¬ active radon, whose longest lived isotope is 222Rn with a half-life 3.82 days. This was discovered inside sealed ampoules of radium in 1900 by F. E. Dorn at Halle in Germany. We now see the noble gases as completing the rows of the periodic table, but chemists were first inclined to place them as group 0 at the start of the table because they had no tendency to form compounds, in other words their valency was 0. Today we put them at the end of the rows of the periodic table since they represent the culmination of adding electrons to a particular electron shell.

The structure of atoms and the periodic table The noble gases completed the format of the periodic table as we know it. In the long form there are seven rows, or periods, with 2,8,8,18,18,32 and 32 elements.18 This pattern can be understood in terms of the underlying electronic structure of atoms, and indeed the pattern is really that of electron shells which hold 2,6,10 and 14 electrons. Combinations of these numbers give rise to 8 (=2 + 6), 18 (=2 + 6 + 10), and32 (=2 + 6+10+14). 18 This last row of the table currently extends to 24 although should eventually reach 32. 274

This underlying structure could only be understood once the nature of the atom was revealed. This puzzle began to unravel with the discovery of the electron in 1896 by J. J. Thompson. A few year after this Lord Rutherford bombarded thin gold foil with a particles, and discovered that atoms of gold must consist of a tiny, posi¬ tively charged nucleus in which almost all the mass was concentrated. In 1913 H. G. J. Moseley (1887-1915) formulated the property of atomic number, which is the number of protons of positive charge in the nucleus. He showed that the sequence of elements in the periodic table was really the order of their atomic numbers. Neils Bohr (1885-1962), that same year, linked the form of the periodic table to the atom¬ ic structure of atoms. He published a periodic table based on electron energy levels in 1923. If the elements are arranged in rows in order of increasing atomic number, and in columns having the same electron outer shell, then we arrive at the long form of the periodic table as shown inside the front cover. Across a row of the periodic table we are adding electrons to a particular shell until that shell is full when we arrive at one of the noble gases. Consequendy these represent a natural break in the table. Despite these advances in atomic theory, Mendeleyev’s eight-column periodic table remained the common type until after World War II. Then the extended or long form slowly displaced it as the man-made elements were announced, and interest centred on the final row. Although the long form of the table can be traced back to Mendeleyev, he championed the eight-column version. The long form was revived by Lang in 1893, and then developed by the great Swiss inorganic chemist Alfred Werner (1866-1919) in 1905 (Fig. 7). The long form of the table was first used in a textbook by H. G. Deming in 1923, and it became popular in America in the 1930s when it was distributed free by the firm Merck & Company. With the resur¬ gence of inorganic chemistry in the 1960s, the new long form eventually triumphed and today is the accepted format for textbooks, posters and educational displays.

Ho

H



Li

N*

Cr

Urn P«

K

c*

Sc

Ti

V

U

Sc

Y

U

Nb Mo ... Ra

c*

Bo

L*

Co

Nd Fr

...

... S*

B* Gd Tk



If

T*

Y

T*

W

... Oo

Co

Nl

Rb

Pd

Ir

ft

Cm

A*

B

C

N

o

P

No

M« Ai

Si

P

s

Cl

A

1m

Go

Go

A*

s*

Br

t/

Cd

J*

So

Sb

To

J

X*

H* Tl

Pb

ftl

Pt>o

Fig. 7 Alfred Werner’s periodic table

To understand the periodic table, it is necessary to realize that atoms have shells and sub-shells of electrons around the nucleus and we can imagine these being filled one-by-one with electrons, starting at the levels of lowest energy nearest the nucleus. Studies of the spectra of atoms showed there to be lines corresponding to the energies of electromagnetic radiation (ultraviolet, visible, and infrared) which represented electrons jumping between these various levels. The spectral lines gave rise to a system of quantum numbers that are related to the electron shells. First there are the principal electron shells and these are numbered according to the principal quantum number, n, which has values 1-7. Each shell has sub-shells and for principal quantum number n there are n of these. They are given a sec¬ ondary quantum number, /, the so-called orbital quantum number, and this can have values of 0, 1, 2 ... (n-1). In other words l is always numerically less than n. This means that for the first shell, where n- 1, there is only the one shell for which l = 0. The values of n and l for the first four shells and sub-shells are as in Table 4.

275

THE PERIODIC TABLE

Table 4 The electron shells and sub-shells which surround the nucleus of an atom Principal shell

Sub-shells

n

l

1 2 3 4

0 0,1 0,1,2 0,1,2,3

Notation 1.0 2.0 3.0 4.0

(Is) (2s), 2.1 (2p) (3s), 3.1 (3p), 3.2 (3d) (4s), 4.1 (4p), 4.2 (4d), 4.3 (4f)

Although l has the mathematical values 0,1,2,3 the common notation for these is s, p, d, f which are based on their spectral lines. Thus the first orbital sub-shell is called Is rather than 1.0, and the second sub-shells are 2s and 2p rather than 2.0 and 2.1. The shells are filled up with electrons in the order of increasing n + l starting with Is, then 2s, 2p, 3s, and so on. If two shells have the same numerical value for n +1 then the one with the smaller n is filled first. For example if n +1 = 4, then of the two combinations 4 + 0 or 3 +1 the latter comes first. The order of filling the electron shells is reflected in the periodic table (see Table 5).

Table 5 The order of filling electrons shells and the periodic table*

row 1 row 2 row 3 row 4 row 5 row 6 row 7

—> —> —> —> —>

s groups

f groups

d groups

p groups

Is 2s 3s 4s 5s 6s 7s

—> —> —» -» 4f (4+3=7) 5f (5+3=8)

-> —> 3d (3+2=5) 4d (4+2=6) 5d (5+2=7) 6d (6+2=8)

2p 3p 4p 5p 6p

(1+0=1) (2+0=2) (3+0=3) (4+0=4) (5+0=5) (6+0=6) (7+0=7)

(2+1=3) (3+1=4) (4+1=5) (5+1=6) (6+1=7)

*The numbers in brackets are n + 1.

The sub-shells can hold increasing numbers of electrons. The s shells can hold 2, the p shells 6, the d shells 10, and the f shells 14. We recognized these are the basis of the various blocks of the periodic table. The s-block elements consist of two groups (numbered 1, the alkali metals, and 2, the alkaline earths), the p-block ele¬ ments consist of six groups (numbered 13 to 18), the d-block elements have ten groups (numbered 3 to 12) and the f-block elements consist of two rows 4f and 5f which are not given group numbers. The format of Table 5 reflects the format of the periodic table in the front of The elements where the elements are grouped into s, p, d, and f blocks. There are versions of the periodic table in which the groups are arranged in order of Z, the secondary quantum number, i.e. s group

p group —> d group —» f group

and while this may seem more logical, it is not possible to place the elements in such tables, based on electron shells, stricdy according to increasing atomic num¬ bers. R. Gardner was the first to suggest such a table in 1930, but they did not catch on because they lack the ordering of elements that chemists expect. For instance the third row of such a table would include the elements of the 4s, 4p, 4d, and 4f groups and reads as follows: 4s

/

4p

/

4d

/

4f

K (19), Ca(20) / Ga(31), Ge(32)... Kr(36) / Y(39), Zr(40)... Cd (48) / La(57), Ce(58)... Yb(70)

The dark side Illuminating as it appears, the periodic table has its dark side. It has led chemists astray, as it did with the tellurium/iodine paradox; it still has its unresolved 276

THE PERIODIC TABLE tensions, and more recently it has led to bitter disputes. One of the latter occurred in the 1970s and 1980s as attempts were made to resolve the conflict between the European and American system of numbering the groups of the periodic table. When the short periodic table of eight groups was turned into the long form of 18 groups, the Europeans numbered the groups on the left half LA to VIII and on the right hand half IB to VTIB with the noble gases being group 0. The Americans on the other hand kept the IA/ IB system of Mendeleyev so that their long form of the table was numbered IA, IIA, etc. for the s- and p-block elements, and IB, IIB, etc. for the d block. Both systems numbered the alkali metals groups IA, and the alkaline earth metals IIA but after that they diverged. Various suggestions were made to resolve the difficulty but finally the International Union of Pure and Applied Chemistry (IUPAC) suggested the groups simply be numbered 1 through to 18 across the periodic table, a scheme that had first been proposed by a Swedish chemist Arne Olander in the 1950s. After much heart searching the American Chemical Society (ACS) finally agreed. The f-block does not fit into this system but this poses no problem since the 4f and 5f periods of elements are best dealt with as rows of the periodic table rather than groups. Renumbering the groups was a storm in a tea cup compared to the controversy of naming new elements. These are mainly the radioactive elements that come beyond uranium, plus the missing ones from the body of the periodic table, ele¬ ments 43 and 61. All these isotopes are radioactive and have long gone from the Earth’s crust. As we have seen, technetium (43) was first made in 1937. Despite several claims to have discovered element 61 in the early years of this century, the first promethium atoms were only made in 1945 by nuclear processes. In discovering these elements the periodic table was useful in that it indicated that they were yet to be found, while suggesting what properties they would have when finally they were discovered. The periodic table was less helpful when attempts were first made to make the elements beyond uranium. The first of these were produced by bombarding this with neutrons. The transuranium elements were expected to be like the ones above them in the periodic tables of the day. For example, uranium came below tungsten in the table19 so the next element should come below rhenium, and the one after that would be below osmium. This misconception led several eminent scientists astray. In the 1930s research in this area was being undertaken by Enrico Fermi and his team in Rome, by Otto Hahn, Lise Meitner, and Fritz Strassmann in Berlin, and by Irene Curie and Paul Savitch in Paris. It was observed that bombarding uranium with neutrons gave a product with a half-life of 2.3 days. However, the new isotope had chemical properties more like uranium than the rhenium it should have re¬ sembled so it was not recognized as a new element. The sequence of neutron bom¬ bardment really had produced a new element. It was correctly identified as such by Edwin MacMillan and Philip Abelson at Berkeley in May 1940 and they named it neptunium. 238U —> 239U (f1/2 = 23 min)—> 239Np (f1/2 = 2.3 days)

The transuranium elements The element with the highest atomic number that can be found as mineral deposits is uranium (92). Elements beyond this need to be synthesized and are called the transuranium elements. There are alternative ways of doing this. Some new elements have been made by bombarding an existing element with neutrons. These are absorbed by the nucleus relatively easily because they are not charged and so are not repelled. However, absorbing a neutron does not in itself create a new element, it merely makes another isotope of the existing element. What it may 19 There are several similarities between the chemistry of these two elements, for example both display a wide range of oxidation states, and they have similar oxides U02 / U205 / U03 and W02 / W205 /wo3. 277

THE PERIODIC TABLE do is to make the nucleus unstable, and this may result in the nucleus ejecting an electron, called a (i particle, which has a negative charge. Consequently the nuclear charge increases by +1, and a new element is formed. This is how neptunium (93), americium (95), einsteinium (99) and fermium (100) were made. Another method of making a new element is to bombard a target of a heavy ele¬ ment with nuclei such as hydrogen (atomic number 1), helium (2), carbon (6), rtitrogen (7), or oxygen (8), hoping thereby to fuse them into the nucleus and so create a new heavier element. The heaviest elements are synthesized this way. The difficulty here is that both target and missile are positively charged and so repel each other. If a new, merged, nucleus is to form then the missile nuclei must have a very high energy. This can be done by accelerating them in machines called cyclotrons running at high voltages. Because the transuranium elements are synthetic, it does not mean that they may not once have existed on Earth. It may simply mean that their half-lives are short compared to the age of our planet, which is about 4.5 billion years old (4.5 x 109 y). For example, even if there had been a million tonnes of neptunium when the Earth was formed there would still have been time for this to undergo over 2000 half lives. In fact it would require only 91 half lives, taking 195 000 000 years, to reduce a million tonnes of neptunium to a single atom. The longest lived isotopes of the transuranium elements are listed in Table 6.

Table 6 The half-lives of the longest lived isotopes of the transuranium elements Atomic number

Element

93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112

neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium rutherfordium dubnium seaborgium bohrium hassium meitnerium un-named un-named un-named

Longest lived isotope

Half life

237Np

266Mt 269 ?

2 140 000 y 82 000 000 y 7370 y 15 600 000 y 1400 y 890 y 275 d 101 d 56 d 58 m 3m 65 s 34 s 27.3 s 0.1 s 2 x 10~3s 3 x 10~3s 1.7 x 10-s ?

277

2.8 x 10"4 s

244pu

2«Am 247Cm 247Bk 25,cf 254Es 257pm

25«Md 259N0 260Lr 26, Rf

2G2Db 266Sg

262Bh 265Hs

The transfermium controversy As Table 6 shows, elements beyond fermium have very unstable nuclei, and it becomes progressively harder to make and detect them. As a result the claims to have discovered them are often disputed. Curiously, although these elements have no use, and little chemistry, each one possesses a trivial feature to which an undue amount of importance is attributed—its name. The first person to make a single atom of one of these heavy elements had the indisputable right to name it. When the discovery was disputed then an element could have more than one name, and this is what happened with elements 104,105, and 106. The first claim for element 104 came in 1964 from a group of of scientists at Dubna, near Moscow, who reported isotope 260. They named the element kurchatovium after Igor Kurchatov, who had developed the Russian atomic bomb. The claim was disputed in 1969 by a group of scientists led by Albert Ghiorso at 278

THE PERIODIC TABLE Berkeley, California, who reported isotope 257 and named it rutherfordium after Lord Rutherford. By bombarding 249Cf with 12C nuclei they made several thousand atoms of element 104. Element 105 was likewise to cause dissent. Two isotopes, 260 and 261, were reported in 1967 by the scientists at Dubna but the element was not given a name, although they later called it nielsbohrium in tribute to Neils Bohr. The claim was disputed in 1970 by the Berkeley group, who reported isotope 260, and named it hahnium after Otto Hahn, the German chemist who first observed uranium fission. Since then several atoms of element 105 have been made from 249Cf by bombarding it with 15N nuclei. Which names should we use? The International Union of Pure and Applied Chemistry (IUPAC) and The International Union of Pure and Applied Physics (IUPAP) are the bodies which confirm names, and they suggested a compromise. Elements 104 and above were to be named according to a system based on the atomic number of the elements. This was derived from Greek and Latin terms in which the digit 0 would be called nil, 1 would be called un, 2 became bi, 3 tri, 4 quad, 5 pent, 6 hex, 7 sept, 8 oct, and 9 was enn. Since all the elements in this part of the periodic table are metals they all were given the ending -ium to their names. Thus element 104 became unnilquadium (un-nil-quad-ium), 105 became unnilpentium, and 106 unnilhexium. This expedient solution was only a temporary one, while the claims and counter-claims of the rival groups were judged. In 1987 IUPAC and IUPAP set up a nine-member committee,20 called the Transfermium Working Group (TWG) to look into the competing priority claims for the discovery of all the transfermium ele¬ ments. They reported their deliberations in 1992 entitled ‘Discovery of the transfer¬ mium elements’, published in full in the journal Progress in Particle and Nuclear Physics 29,453. The TWG confirmed that there could be no dispute about the discovery and naming of mendelevium (101), which was discovered by the group at The Lawrence Berkeley Laboratory in Berkeley, California; nor about nobelium (102), which was first reported by the group at the Joint Institute for Nuclear Research at Dubna, near Moscow. Lawrencium (103) was reported with varying degrees of completeness and conviction by both Berkeley and Dubna over a period of years and credit should be shared by both. The TWG came to the same conclusion for elements 104 and 105. Element 106 was also claimed both by the Americans and the Russians but the TWG confirmed the US claim that element 106 was conclusively proved in 1974 by teams at the Lawrence Berkeley Laboratory in Berkeley, California and the Lawrence Livermore National Laboratory led by Ghiorso. He announced the name of the element as seaborgium in March 1994, in honour of Glenn Seaborg who had been instrumental in producing several transuranium elements after World War II. Several atoms of seaborgium have been made by bombarding 249Cf with 180 nuclei using an 88-inch-diameter cyclotron which produces about a billion atoms per hour of which only one is seaborgium. Element 107 was first made in 1981 at the nuclear research facility Gesellschaft fur Schwerionenforschung (GSI) in Darmstadt, Germany and was named niels¬ bohrium. Peter Armbruster, Gottfried Miinzenberg and their co-workers at the heavy ion research facility are credited with the discovery. The Dubna group had reported it earlier but the TWG found their evidence unconvincing. The Darmstadt group used the so-called cold fusion method in which a target of bismuth was bom¬ barded with atoms of chromium and an atom of the element 107 was detected. In 1984 Peter Armbruster, Gottfried Miinzenberg, and their co-workers at GSI again were the first to make hassium, whose name they derived from Hassia, the Latin name for Hesse, the German state in which GSI is located. The Russian group at Dubna also produced element 108 in the same year, but the TWG decided that 20 Its members were R. C. Barber, N. N. Greenwood, A.Z. Hrynkiewicz, Y. P. Jeannin, M. Lefort, S. Sakai, I. Ulehia, A. H. Wapstra, and D. H. Wilkinson. 279

THE PERIODIC TABLE the major credit should to to the Darmstadt group. They again used the so-called cold fusion method in which a target of lead was bombarded with atoms of iron to give an atom of hassium. The IUPAC committee thought the German state of Hesse did not merit naming an element in its honour and suggested hahnium instead, thereby adding to the confusion because the American Chemical Society had given this to element 105. Element 109 was discovered in 1982, and in fact was found before element 108. It too was made by Peter Armbruster, Gottfried Mitnzenberg, and their co-workers at GSI. They named it meitnerium, after the Austrian physicist Lise Meitner, who was the first scientist to realize that spontaneous nuclear fission was possible.21 A single atom of meitnerium was made by the cold fusion method in which a target of bismuth was bombarded with atoms of iron, and to date fewer than ten atoms of this element have been produced. To resolve disputes over names, formulas, and symbols, chemists turn to IUPAC. They considered the problem and came up with an approved set of names for these new elements: 104 was to be dubnium; 105 jolontium; 106 rutherfordium; 107 bohrium; 108 hahnium, and 109 meitnerium. In choosing these names they ignored the wishes of the undisputed discoverers of elements 106 (seaborgium) and 108 (hassium). As might be imagined, few chemists were happy with the new names, especially as they conflicted with those already in use by the American Chemical Society. IUPAC was urged to think again and in February 1997 it came up with a revised list of names which took into account the wishes of the discoverers and the sensibil¬ ities of national groups. The approved names of the transfermium elements are now: • 101 mendelevium (Md) *104 rutherfordium (Rf) • 102nobelium (No) • 105 dubnium (Db) • 103 lawrencium (Lr) • 106 seaborgium (Sg)

• 107 bohrium (Bh) • 108 hassium (Hs) • 109 meitnerium (Mt)

There is little doubt that these will be used, albeit rarely, because there will never be much chemistry to report for these elusive elements, nor for those which immedi¬ ately follow them. Late in 1994 elements 110 and 111 were reported by Armbruster. A single atom of the former was made by accelerating nickel atoms through 311 MeV and bom¬ barding a spinning lead target. Its half-life was 0.17 milliseconds, and it decays by emitting an a particle rather than undergoing nuclear fission. A single atom of ele¬ ment 111 was made similarly. In 1996 Armbruster reported element 112, made by fusing zinc and lead nuclei. This had a half-life of 0.28 milliseconds and also decayed by a emission.22 The half-life and decay of element 112 hints at increased nuclear stability, although this is not immediately apparent from Table 6. Yet this ‘stability’ is not so strange as it appears. Several years ago it was suggested that as the atomic number increased we would reach an ‘island of stability’ for those elements that came at the bottom of the p block of elements, and especially for the one which comes below lead in the table. This would be element 114, and isotope-298 (114 protons and 184 neutrons) would be particularly stable. This isotope corresponds to energy levels within the nucleus being complete—rather like electron energy levels around the nucleus being filled when an atom is a noble gas. Elements adjacent to 114 would also have enhanced stability of the nucleus so that element 112 (below mercury), element 113 (below thallium) and element 115 (below bismuth) might all have isotopes that would be stable enough for them to be collected, and from which chemical compounds might even be made. This island of 21 This belated tribute to Lise Meitner (1878-1968) was well deserved. She and Otto Hahn had discovered protactinium in 1917. Lise was also instrumental in discovering nuclear fission, although this was not recognized when Hahn was awarded the Nobel Prize for chemistry in 1944. She had fled Germany in 1938, when her native Austria was annexed by the Nazis. 22 These elements have yet to be named and are not included in the main tables of The elements. 280

THE PERIODIC TABLE stability is expected to extend to element 118, which would complete row 7p at the bottom of the p block of the periodic table. Even though we may never reach the elements of the island of stability we can predict what element 114 will be like because it will come below lead in the table. Assuming the half-life of one of its isotopes was long lived, enough for there to be weighable quantities of the element produced, we would expect it to be a soft metal with a low melting point and a very high density. Its most stable oxide would be MO, and chloride MC12. There should also be a higher oxide M02, and chloride MC14. There would be salts of the ion M2+ and possibly complex ions of the higher oxida¬ tion state M4+, such as MCI,A and maybe even MC184_ since its large size should enable more chloride ions to surround it than surround lead in PbCl62-. It would of course be debatable whether these ions could withstand the intense radioactivity of the element, and so they might never be prepared.

Misplaced elements? There are three elements which pose problems of location in any periodic table. These are hydrogen (1), lanthanum (57), and actinium (89). Hydrogen has an electron configuration Is which should place it in the s block of the table above lithium (2s) and this is where it is to be found in some tables. But hydrogen is not a metal like lithium. Indeed by the same logic the noble gas helium (Is2) should therefore be placed above beryllium, but no form of the table places it so because it is clearly a noble gas and must go above neon even though this has the electron configuration of a filled p shell. Some tables place hydrogen by itself, or with helium, in the very centre of the table, floating free above the other elements. Others place hydrogen above fluorine, although it shares little in common with the halogen gases. Some authors give it double billing and place it above both lithium and fluorine. In The Elements I have placed it next to helium and above fluorine and neon, but put both of them in a separate block, labelled Is, as a mark of thenuniqueness. The other problem concerns the f block of elements which comes between the s block and d block at the bottom of the table. For reasons of economy of space this block is generally written below the d block, as in the inside front cover. Which ele¬ ments belong to the f block? Traditionally, and for historical reasons, lanthanum and actinium are placed in group 3, below scandium and yttrium. After lanthanum come the other so-called rare earths or lanthanides, which are in fact the upper row of the f block and this begins with cerium. After actinium comes the actinides, the lower row of the f block, which starts with thorium. This arrangement, common in chemistry textbooks, has been challenged as ill-judged. The weight of evidence is that lanthanum and actinium are the first members of the respective rows of the f block. The rows of the f block have 14 elements and so the final ones in each row are ytterbium and nobelium respectively. In 1982 William B. Jensen argued cogently for this change to be made to periodic tables in an article in the Journal of Chemical Education, volume 59, page 634. The reasons he gives seem indisputable and based entirely on the physical and chemical properties of these elements, and conse¬ quently I have chosen this arrangement for The elements. The periodic table is the hallmark of inorganic chemistry. It summarizes the chemical elements in a simple yet logical table that can even be made into a work of art. As long as chemistry is studied there will be a periodic table. And even if some¬ day we communicate with another part of the universe, we can be sure that one thing both cultures will have in common is an ordered system of the elements that will be instantly recognizable by both intelligent life forms.

Further reading Abelson,P.H. (1992) ‘Discovery of neptunium’ Transuranium elements (ed. Morss, L.R. and Fuger, J.) American Chemical Society, Washington DC. Bensaude-Vincent,B.(1984) ‘La genesedu tableau de Mendeleev’ in La Recherche, 15,1206. Brock, W.H. (1992) The Fontana History of Chemistry, Fontana Press, London. 281

THE PERIODIC TABLE Cassebaum,H. and Kauffman, G.B., (1971) Isis, 62,314. Emsley, J. ‘Mendeleyev’s dream table’ in New Scientist, 7 March 1984. Emsley, J. (1987) ‘The development of the periodic table of the chemical elements’ in Interdisciplinary Science Reviews, 12,23. Gilreath, E.S. (1958) Fundamental concepts of inorganic chemistry, McGraw-Hill, New York. Holden, N.E. (1984) ‘Mendeleyev and the periodic classification of the elements 'Chemistry International, 6,18. Mazurs, E.G. (1974) Graphic representations of the periodic system during one hundred years, University of Alabama Press, Tuscloosa. Rouvray, D.H. (1994) ‘Turningthe tables on Mendeleev’ in Chemistry in Britain, May, 373. Sanderson, R.T. (1967) Inorganic Chemistry, Reinhold Publishing Corp., New York,. Scerri, E.R. (1994) ‘Plus ga change... ’ in Chemistry in Britain, May, 379. Seaborg,G.T. (1990) The Elements Beyond Uranium, JohnWiley&SonsInc.,NewYork. Van Spronsen, J.W. (1969) The periodic system of chemical elements: a history of the first hundred years, Elsevier, Amsterdam. Venables, F.P.(1896) The development of the periodic law. Chemical Publishing Co., Easton, PA. Weeks, M.E. and Leicester, H.M. (1968) Discovery of the elements (7th edn), Chapter 14, Journal of Chemical Education, Easton, PA.

282

The discovery of the elements

There now follows two listings, the first in chronological order of discovery, the sec¬ ond with the elements in order of increasing atomic number.

Discovery of the elements in chronological order Year

Element

Discoverer

Place

The ancient world pre-history pre-history c.5000 bc c.3000 bc c.3000 bc c.2500 bc c.2100 bc c.1600 bc c.1500 bc c.1000 bc

Carbon Sulfur Copper Silver Gold Iron Tin Antimony Mercury Lead

-

-

— —

— — — -

The Middle Ages c.1250 pre-1500* c.1500 1669 pre-1700

Arsenic Zinc Bismuth Phosphorus Platinum

Magnus -

-

-



Brandt, H. -

Hamburg -

Brandt, G. Cronstedt Black Cavendish Rutherford Scheele Priestley Scheele Grahn Vauquelin Hjelm von Reichenstein Elhuijar and Elhuijar Klaproth Klaproth Gregor Klaproth Gadolin Vauquelin

Stockholm Stockholm Edinburgh London Edinburgh Uppsala Leeds Uppsala Stockholm Paris Uppsala Sibiu, Romania Vergara, Spain Berlin Berlin Creed, Cornwall Berlin Abo, Finland Paris

del Rio Hatchett

Mexico London

Germany

The eighteenth century 1735 1751 1755 1766 1772 1772

Cobalt Nickel Magnesium Hydrogen Nitrogen Oxygen

1774 1774 1780 1781 1783 1783 1789 1789 1791

Chlorine Manganese Chromium Molybdenum Tellurium Tungsten Zirconium Uranium Titanium

1794 1797

Yttrium Beryllium

The nineteenth century 1801 1801

Vanadium Niobium

* Zinc was known as the copper-zinc alloy, brass, around 20 bc. 283

THE 1DISCOVERY OF THE ELEMENTS

1802 1803 1803 1803 1803 1803

Tantalum Rhodium Palladium Osmium Iridium Cerium

1807 1807 1808

Davy Davy Lussac and Thenard Davy Calcium Davy Crawford Strontium Ruthenium Sniadecki Davy Barium Iodine Courtois Thorium Berzelius Lithium Arfvedson Berzelius Selenium Davy Cadmium Silicon Berzelius Aluminium Oersted Bromine Balard Lowig Lanthanum Mosander Erbium Mosander Mosander Terbium Caesium Bunsen and Kirchhoff Rubidium Bunsen and Kirchhoff Thallium Crookes Reich and Richter Indium de Boisbaudran Gallium Holmium Cleve Delafontaine and Soret Ytterbium de Marignac Scandium Nilson Samarium de Boisbaudran Thulium Cleve Gadolinium de Marignac Praseodymium von Welsbach Neodymium von Welsbach Germanium Winkler Fluorine Moissan Dysprosium de Boisbaudran Argon Rayleigh and Ramsay Helium Ramsay Krypton Ramsay and Travers Neon Ramsay and Travers Xenon Ramsay and Travers Polonium Curie (Marie) Radium Curie and Curie Actinium Debierne

1808 1808 1808 1808 1811 1815 1817 1817 1817 1824 1825 1826 1839 1842 1843 1860 1861 1861 1863 1875 1878 1878 1879 1879 1879 1880 1885 1885 1886 1886 1886 1894 1895 1898 1898 1898 1898 1898 1899

Ekeberg Wollaston Wollaston Tennant Tennant Berzelius and Hisinger

Potassium Sodium Boron

Uppsala London London London London Vestmanland, Sweden London London Paris London London Edinburgh Vilno, Poland London Paris Stockholm Stockholm Stockholm London Stockholm Copenhagen Montpellier Heidelberg Stockholm Stockholm Stockholm Heidelberg Heidelberg London Freiberg Paris Uppsala Geneva Geneva Uppsala Paris Uppsala Geneva Vienna Vienna Freiberg Paris Paris London and Bristol London London London London Paris Paris Paris

The twentieth century 1900 1901 284

Radon Europium

Dorn Demargay

Halle Paris

THE DISCOVERY OF THE ELEMENTS 1907

Lutetium

1958 1961 1964

Urbain James Protactinium Hahn and Meitner Fajans Soddy, Cranston, and Fleck Hafnium Coster and Hevesey Rhenium Noddack, Tacke, and Berg Technetium Perrier, and Segre Francium Perey Neptunium McMillan and Abelson Astatine Corson, Mackenzie, and Segre Plutonium Seaborg, Wahl and Kennedy Americium Seaborg, James, Morgan and Ghiorso Curium Seaborg, James, and Ghiorso Promethium Marinsky, Glendenin, and Coryell Berkelium Thompson, Ghiorso, and Seaborg Californium Thompson, Street, Ghiorso, and Seaborg Einsteinium Choppin, Thompson, Ghiorso, and Harvey Fermium Choppin, Thompson, Ghiorso, and Harvey Mendelevium Ghiorso, Harvey, Choppin, Thompson and Seaborg Nobelium Various Lawrencium Ghiorso, Sikkeland, Larsh Rutherfordium Various

1967

Dubnium

Various

1974 1981

Seaborgium Bohrium

1982

Meitnerium

1984

Hassium

1994

Element 110

1994

Element 111

1996

Element 112

Ghiorso, and others Armbruster, Gottfried Mtinzenberg, and others Armbruster, Gottfried Miinzenberg, and others Armbruster, Gottfried Miinzenberg, and others Armbruster, Hofmann and others Armbruster, Hofmann and others Armbruster, Hofmann and others

1917

1923 1925 1937 1939 1940 1940 1940 1944 1944 1945 1949 1950 1952 1952 1955

Paris New Hampshire, USA Berlin Karlsruhe Glasgow Copenhagen Berlin Palermo Paris Berkeley, California Berkeley, California Berkeley, California Chicago Berkeley, California Oak Ridge, USA Berkeley, California Berkeley, California Berkeley, California Berkeley, California Berkeley, California Dubna, Moscow Berkeley, California Dubna, Moscow and Berkeley, California Dubna, Moscow and Berkeley, California Berkeley, California Darmstadt, Germany Darmstadt, Germany Darmstadt, Germany Darmstadt, Germany Darmstadt, Germany Darmstadt, Germany

285

THE DISCOVERY OF THE ELEMENTS

Discovery of the elements in order of atomic number Element 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

Year

Discoverer

Cavendish Ramsay Arfvedson Vauquelin Lussac and Thenard Davy pre-history Carbon Rutherford Nitrogen 1772 Scheele 1772 Oxygen Priesdey Moissan Fluorine 1886 Ramsay and Travers Neon 1898 Davy Sodium 1807 Black Magnesium 1755 Oersted Aluminium 1825 Silicon 1824 Berzelius Brandt, H. Phosphorus 1669 pre-history Sulfur Chlorine 1774 Scheele Rayleigh and Ramsay Argon 1894 Davy Potassium 1807 Davy Calcium 1808 Scandium Nilson 1879 Titanium 1791 Gregor Klaproth Vanadium 1801 del Rio Chromium Vauquelin 1780 Manganese 1774 Grahn Iron c.2500 bc Cobalt 1735 Brandt, G. Nickel 1751 Cronstedt Copper c.5000 bc Zinc pre-1500* Gallium 1875 de Boisbaudran Germanium 1886 Winkler Arsenic c.1250 Magnus Selenium 1817 Berzelius Bromine 1826 Balard Lowig Krypton 1898 Ramsay and Travers Rubidium 1861 Bunsen and Kirchhoff Strontium 1808 Crawford Yttrium 1794 Gadolin Zirconium 1789 Klaproth Niobium 1801 Hatchett Molybdenum 1781 Hjelm Technetium 1937 Perrier and Segre Ruthenium 1808 Sniadecki Rhodium 1803 Wollaston Palladium 1803 Wollaston Silver c.3000 bc Cadmium 1817 Davy Indium 1863 Reich and Richter Hydrogen Helium Lithium Beryllium Boron

1766 1895 1817 1797 1808

* Zinc was known as the copper-zinc alloy, brass, around 20 bc. 286

Place London London Stockholm Paris Paris London Edinburgh Uppsala Leeds Paris London London Edinburgh Copenhagen Stockholm Hamburg Uppsala London and Bristol London London Uppsala Creed, Cornwall Berlin Mexico Paris Stockholm -

Stockholm Stockholm -

Paris Freiberg Germany Stockholm Montpellier Heidelberg London Heidelberg Edinburgh Abo, Finland Berlin London Uppsala Palermo Vilno, Poland London London -

London Freiberg

THE DISCOVERY OF THE ELEMENTS 50 51 52 53 54 55 56 57 58

Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium

59 60 61

Praseodymium 1885 Neodymium 1885 Promethium 1945

62 63 64 65 66 67

Samarium Europium Gadolinium Terbium Dysprosium Holmium

1879 1901 1880 1843 1886 1878

68 69 70 71

Erbium Thulium Ytterbium Lutetium

1842 1879 1878 1907

72 73 74 75 76 77 78 79 80 81 82 83 84 85

Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury Thallium Lead Bismuth Polonium Astatine

86 87 88 89 90 91

Radon Francium Radium Actinium Thorium Protactinium

1900 1939 1898 1899 1815 1917

92 93 94 95

Uranium Neptunium Plutonium Americium

1789 1940 1940 1944

96 97

Curium Berkelium

1944 1949

c.2100 bc

-

-

c.1600 bc 1783 1811 1898 1860 1808 1839 1803

von Reichenstein Courtois Ramsay and Travers Bunsen and Kirchhoff Davy Mosander Berzelius and Hisinger

-

1923 1802 1783 1925 1803 1803 pre-1700 c.3000 bc c.1500 bc 1861

von Welsbach von Welsbach Marinsky, Glendenin and Coryell de Boisbaudran Demargay de Marignac Mosander de Boisbaudran Cleve Delafontaine and Soret Mosander Cleve de Marignac Urbain lames

Sibiu, Romania Paris London Heidelberg London Stockholm Vestmanland, Sweden Vienna Vienna Oak Ridge, USA

Coster and Hevesey Ekeberg Elhuijar and Elhuijar Noddack, Tacke and Berg Tennant Tennant -

Paris Paris Geneva Stockholm Paris Uppsala Geneva Stockholm Uppsala Geneva Paris New Hampshire, USA Copenhagen Uppsala Vergara, Spain Berlin London London -

-

-

Crookes

London

c.1000 bc

-

c.1500 1898 1940

-

Curie (Marie) Corson, Mackenzie and Segre Dorn Perey Curie and Curie Debierne Berzelius Hahn and Meitner Fajans Soddy, Cranston and Fleck Klaproth McMillan and Abelson Seaborg, Wahl and Kennedy Seaborg, lames, Morgan and Ghiorso Seaborg, James and Ghiorso Thompson, Ghiorso and Seaborg

Airis Berkeley, California Halle Paris Paris Paris Stockholm Berlin Karlsruhe Glasgow Berlin Berkeley, California Berkeley, California Chicago Berkeley, California Berkeley, California

287

THE DISCOVERY OF THE ELEMENTS 98

Californium

1950

102 Nobelium 1958 1961 103 Lawrencium 104 Rutherfordium 1964

Thompson, Street, Ghiorso and Seaborg Choppin, Thompson Ghiorso and Harvey Choppin, Thompson, Ghiorso and Harvey Ghiorso, Harvey, Choppin, Thompson and Seaborg Various Ghiorso, Sikkeland, Larsh Various

99

Einsteinium

1952

105 Dubnium

1967

Various

106 Seaborgium 107 Bohrium

1974 1981

108 Hassium

1984

109 Meitnerium

1982

110 Un-named

1994

ill

Un-named

1994

112 Un-named

1996

Ghiorso, and others Armbruster, Gottfried Miinzenberg, and others Armbruster, Gottfried Miinzenberg, and others Armbruster, Miinzenberg and others Armbruster, Hofmann and others Armbruster, Hofmann and others Armbruster, Hofmann and others

100 Fermium

1952

101 Mendelevium

1955

288

Berkeley, California Berkeley, California Berkeley, California Berkeley, California Dubna, Moscow Berkeley, California Dubna, Moscow and Berkeley, California Dubna, Moscow and Berkeley, California Berkeley, California Darmstadt, Germany Darmstadt, Germany Darmstadt, Germany Darmstadt, Germany Darmstadt, Germany Darmstadt, Germany

The abundance of elements in the Earth’s crust The following figures give the weight in parts per million, which is equivalent to grams per tonne, and they are arranged in order of decreasing abundance. 8 Oxygen 474 000 14 Silicon 277 000 13 Aluminium 82 000 26 Iron 41000 20 Calcium 41000 11 Sodium 23 000 12 Magnesium 23 000 19 Potasium 21000 22 Titanium 5600 1 Hydrogen 1520 15 Phosphorus 1000 25 Manganese 950 9 Fluorine 950 56 Barium 500 6 Carbon 480 38 Strontium 370 16 Sulfur 260 40 Zirconium 190 23 Vanadium 160 17 Chlorine 130 24 Chromium 100 37 Rubidium 90 28 Nickel 80 30 Zinc 75 58 Cerium 68 29 Copper 50 60 Neodymium 38 57 Lanthanum 32 39 Yttrium 30 7 Nitrogen 25 3 Lithium 20 27 Cobolt 20 41 Niobium 20 31 Gallium 18 21 Scandium 16 82 Lead 14 90 Thorium 12 5 Boron 10 59 Praseodymium 9.5 62 Samarium 7.9 64 Gadolinium 7.7 66 Dysprosium 6 70 Ytterbium 5.3 3.8 68 Erbium 72 Hafnium 3.3 55 Caesium 3 4 Beryllium 2.6 92 Uranium 2.4 50 Tin 2.2 63 Europium 2.1 73 Tantalum 2 32 Germainium 1.8 33 Arsenic 1.5 42 Molybdenum 1.5 67 Holmium 1.4 18 Argon 1.2

65 74 81 71 69 35 51 53 48 47 34 80 49 83 2 52 79 44 78 46 75 45 76 10 36 77 54 88 84 85 86 89 91 94 43 61 87 93 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 HO ill 112

Terbium Tungsten Thallium Lutetium Thulium Bromine Antimony Iodine Cadmium Silver Selenium Mercury Indium Bismuth Helium Tellurium Gold Ruthenium Platinum Palladium Rhenium Rhodium Osmium Neon Krypton Iridium Xenon Radium Polonium Astatine Radon Actinium Protactinium Plutonium Technetium Promethium Francium Neptunium Americium Curium Berkelium Califorium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Un-named Un-named Un-named

1.1 1 0.6 0.51 0.48 0.37 0.2 0.14 0.11 0.07 0.05 0.05 0.049 0.048 0.008 c.0.005 0.0011 c.0.001 c.0.001 6 X 10^ 4 X 10”4 2 X 10^ 1 X 10^ 7 X 10-5 1 X 10“5 3 X 10-6 2 X 10“6 6 X 10~7 trace trace trace trace trace trace nil trace trace trace nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil 289

Index

The following is an alphabetical listing of the information included under each element and the section where it is to be found; ‘heading’ means it is in the information boxes at the top of each page.

A

abundances: geological data table of, 289 allotropes: physical data annual production of elements: geological data Atlantic ocean: geological data atomic mass of nuclei: nuclear data atomic number: front endpapers and heading atomic radius: chemical data atomic spectral lines: electron shell data atomic weights: front endpapers and heading

electronic configuration: electron shell data elements in human being: biological data discoveries: headings, 283-8 seawater: geological data enthalpy of formation of gaseous atoms: physical data enthalpy of fusion: physical data enthalpy of vaporization: physical data entropy: physical data evaporation see enthalpy of vaporization F

B

biological role: biological data blood, concentration in: biological data boiling points: physical data bond energies: chemical data bond lengths: chemical data bone, concentration in: biological data

C CAS number: heading cell dimensions: crystal data chemical compounds: chemical data chemical formulae: back endpapers and heading chlorides: chemical data classification of behaviour in seawater: geological data coefficient of linear expansion: physical data concentrations in human tissue: biological data covalent bonds: chemical data covalent radius: chemical data crystal structure: crystal data crystal forms: crystal data D

density: physical data description of element: chemical data dietary intake: biological data discoverers: heading and table, 283-8 E

Earth’s crust, abundance: geological data effective nuclear charge: chemical data Clementi Froese-Fischer Slater electrical resistivity: physical data electron affinity: electron shell data electron binding energies: electron shell data electronegativity: chemical data absolute Allred Pauling

fluorides: chemical data frequency, NMR: nuclear data geological data

G Gibbs free energy: physical data Gibbs function: physical data ground state electron configuration: electron shell data H

half-lives of isotopes: nuclear data health hazard: biological data heat of fusion: physical data heat of vapourization: physical data

ionic radius: chemical data ionization energies: electron shell data ionization potential: electron shell data isotopes: nuclear data abundance nuclides atomic mass half-lives decay modes nuclear spin uses L

lethal intake: biological data levels of element in humans: biological data blood bone muscle liver total mass in average person linear thermal expansion: physical data M

magnetic susceptibility: physical data magnetogyric ratio: nuclear data medical isotopes: nuclear data melting point: physical data 291

THE KEY TO THE ELEMENTS minerals: geological data appearance density formula hardness molar volume: physical data muscle, see levels of elements N

names: heading derivation french german italian pronunciation Spanish natural isotope abundance: nuclear data neutron capture cross-section: crystal data NMR nuclear magnetic resonance: nuclear data frequency reference compounds sensitivity receptivity magnetogyric ratio nuclear spin: nuclear data nuclides: nuclear data 0 oceans, abundance: geological data ores: geological data oxidation states: chemical data oxides: chemical data P

Pacific ocean, concentrations: geological data Periodic table: 261-82 pronunciation of name: heading

atomic covalent ionic metallic van der Waals reactivity towards: chemical data acids air water receptivity, see NMR: nuclear data reduction potentials: chemical data relative atomic mass: heading reserves of elements: geological data residence times in oceans: geological data resistivity: physical data S

seawater: geological data Atlantic classification concentration Pacific residence time oxidation state sensitivity, NMR: nuclear data specific heat: physical data spin, nuclear: nuclear data standard reduction potentials: chemical data structure, crystal: crystal data sun, abundance in: geological data T

term symbol: electron shell data thermal conductivity: physical data thermal neutron capture cross-section: crystal data toxic intake: biological data toxicity: biological data V

Q quadrupole moment: nuclear data

van der Waals radius: chemical data wavelengths, atomic spectrum

R

X

radioactive isotopes: nuclear data radius: chemical data

X-ray diffraction absorption coefficient: crystal data

292

The elements in alphabetical order with formulae and atomic numbers Actinium Aluminium Americium Antimony Argon Arsenic Astatine Barium Berkelium Beryllium Bismuth Bohrium Boron Bromine Cadmium Caesium Calcium Californium Carbon Cerium Chlorine Chromium Cobolt Copper Curium Dubnium Dysprosium Einsteinium Erbium Europium Fermium Fluorine Francium Gadolinium Gallium Germanium Gold Hafnium Hassium Helium Holmium Hydrogen Indium Iodine Iridium Iron Krypton Lanthanum Lawrencium Lead Lithium Lutetium Magnesium Manganese

Ac A1 Am Sb At As At Ba Bk Be Bi Bh B Br Cd Cs Ca Cf C Ce Cl Cr Co Cu Cm Db Dy Es Er Eu Fm F Fr Gd Ga Ge Au Hf Hs He Ho H In I Ir Fe Kr La Lr Pb Li Lu Mg Mn

89 13 95 51 18 33 85 56 97 4 83 107 5 35 48 55 20 98 6 58 17 24 27 29 96 105 66 99 68 63 100 9 87 64 31 32 79 72 108 2 67 1 49 53 77 26 36 57 '103 82 3 71 12 25

Meitnerium Mendelevium Mercury Molybdenum Neodymium Neon Neptunium Nickel Niobium Nitrogen Nobelium Osmium Oxygen Palladium Phosphorus Platinum Plutonium Polonium Potassium Praseodymium Promethium Protactinium Radium Radon Rhenium Rhodium Rubidium Ruthenium Rutherfordium Samarium Scandium Seaborgium Selenium Silicon Silver Sodium Strontium Sulfur Tantalum Technetium Tellurium Terbium Thallium Thorium Thulium Tin Titanium Tungsten Uranium Vanadium Xenon Ytterbium Yttrium Zinc Zirconium

Mt Md Hg Mo Nd Ne Np Ni Nb N No Os O Pa P Pt Pu Po K Pr Pm Pa Ra Rn Re Rh Rb Ru Rf Sm Sc Sg Se Si Ag Na Sr S Ta Tc Te Tb Tl Th Tm Sn Ti W

u V Xe Yb Y Zn Zr

109 ' 101 80 42 60 10 93 28 41 7 102 76 8 46 15 78 94 84 19 59 61 91 88 86 75 45 37 44 104 62 21 106 34 14 47 11 38 16 73 43 52 65 81 90 69 50 22 74 92 23 54 70 39 30 40

The elements in alphabetical order of formula with names and atomic numbers Ac Ag Al Am Ar As At Au B Ba Be Bh Bi Bk Br C Ca Cd Ce Cf Cl Cm Co Cr Cs Cu Db Dy Er Es Eu F Fe Fm

Actinium Silver Aluminium Americium Argon Arsenic Astatine Gold Boron Barium Beryllium Bohrium Bismuth Berkelium Bromine Carbon Calcium Cadmium Cerium Californium Chlorine Curium Cobolt Chromium Caesium Copper Dubnium Dysprosium Erbium Einsteinium Europium Fluorine Iron Fermium

Cm

Cvonrinim

89 47 13 95 18 33 85 79 5 56 4 107 83 97 35 6 20 48 58 98 17 96 27 24 55 29 105 66 68 99 63 9 26 100 07 /

1

Mg Mn Mo Mt N Na Nb Nd Ne Ni No Np 0 Os P Pa Pb Pd Pm Po Pr Pt Pu Ra Rb Re Rf Rh Rn Ru C o Sa Sb Sc Se sg Si Sn Sr Ta Tb Tc Te Th Ti Tl Tm U V W Xe Y Yb Zn Zr

Magnesium Manganese Molybdenum Meitnerium Nitrogen Sodium Niobium Neodymium Neon Nickel Nobelium Neptunium Oxygen Osmium Phosphorus Protactinium Lead Palladium Promethium Polonium Praseodymium Platinum Plutonium Radium Rubidium Rhenium Rutherfordium Rhodium Radon Ruthenium Sulfur Samarium Antimony Scandium Selenium Seaborgium Silicon Tin Strontium Tantalum Terbium Technetium Tellurium Thorium Titanium Thallium Thulium Uranium Vanadium Tungsten Xenon Yttrium Ytterbium Zinc Zirconium

12 25 42 109 7 11 41 60 10 28 102 93 8 76 15 91 82 46 61 84 59 78 94 88 37 75 104 45 86 44 16 62 51 21 34 106 14 50 38 73 65 43 52 90 22 81 69 92 23 74 54 39 70 30 40

THIRD EDITION The third edition of this widely acclaimed reference book collects together the most important facts about all the chemical elements in a single volume. In addition to chemical, physical, nuclear, and electron data, this edition includes new sections on crystal, biological, and geological data. The alphabetical format of the earlier versions has been retained. Also included are the six newly approved IUPAC names of the elements 104-109; rutherfordium, dubnium, seaborgium, bohrium, hassium, and meitnerium. This handy reference guide is for chemists, physicists, spectroscopists, geologists, life scientists, and environmentalists.

Extra data, in the new edition includes • Foreign names of the elements • Guide to pronunciation • CAS numbers • Health hazards • Toxicity, including LD50 and human exposure • Expanded tables of isotopes • Electron binding energies •Table of minerals • Availability of samples and associated hazards • Neutron scattering lengths • Four new elements • New chapter on the discovery and development of the periodic table

From reviews of previous editions Packed with useful data... I’d recommend that everyone who ever needs data on the elements obtain a copy. Journal of Chemical Education A major achievement... Highly recommended Education in Chemistry This is a marvellous book... excellent value for money. I do not know how I managed to survive without it. Talanta An excellent book which should be in the hands of all laboratory practitioners and students ... now it is available it will be difficult to do without it. Trends in Analytical Chemistry 1 G LI' i J EE/LSLEY is Science Writer in Residence at the Department of Chemistry at the University of Cambridge.

ISBN 0-19-855818-X

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