Crystal Structures - Volume 2 [II, 2 ed.] 0470968621, 9780470968628

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Preface

The second volume of Crystal Structures closely follows the format adopted for Volume 1. As this attempt to provide a unified statement of the atomic positions in all analyzed crystals progresses, improvements become possible. The principal one introduced with this volume is a more reliable bibliography. The author is indebted to his wife for undertaking to control the accuracy of all the bibliographic entries. As the older references are checked, errors carried over from the earlier compilations are being corrected. It is hoped that with time these can all be eliminated. In the meantime readers will find the bibliography of this volume more accurate than that of the loose-leaf edition. As the work on compilation proceeds, the author becomes increasingly aware of the incompleteness of the simple statement of atomic positions. principal coordination relationships, and bond lengths that were the basic objectives of this work. For many purposes it would be desirable to have a fuller listing of interatomic distances and a more explicit evaluation of the accuracy of each determination of structure. Thermal parameters have an essential place in a complete description of atomic arrangement as has also a more detailed discussion of the disorder being found in many crystals. Undoubtedly these should in the long run find a place in the kind of summary Crystal Structures aims to provide. The author has been tempted to initiate such an expanded description immediately, but the critical evaluation of existing data this would require would very materially add to the task of bringing the compilation up to date. It has accordingly seemed more useful to retain the present limited objectives and to complete the survey as quickly as may be, reserving a more expanded coverage to the future. An explanation should be given of the system followed in making the illustrations. They include drawings used in both The Structure of Crystals and the previous edition of Crystal Structures; some, therefore. date back as much as forty years. In earlier days left-hand axes were in common use and the author has continued to employ them even though right-hand systems are now in many circles considered standard. When the time came to prepare this edition, it was apparent that there would be real advantages in adopting this right-hand system but by then so many drawings had been made according to the earlier convention that remaking them was impractical. It was therefore decided to continue with left-hand axes rather than to have an indiscriminate mixture of the two. There are a few exceptions v

Contents

V. Structures of Complex Binary Compounds RnX m. A. Compounds R 2Xa . B. Compounds of the Type RX a C. Compounds of the Type RX 4 D. Compounds of the Type R aX 4 E. Compounds R nX 5 • F. Compounds of the Type RnX m (rn ~ 6) Bibliography, Chapter V VI. Structures of the Compounds R(lVIX2 )n Bibliography, Chapter VI . VII. Compounds of the Type R n(l\1Xa) p A. Compounds RIVlX a . B. Compounds R n(l\1X 3)m Bibliography, Chapter VII

1 1

45 127 149 170 202 247 277 348

359 359 459 542 565 579

Name Index . Formula Index

vii