Crystal Structure Descriptions
In this appendix, most of the crystal structure types introduced in the main text are formally described by means of their chemical formulas, StrukturBericht symbols, space groups, lattice parameters, special atom positions, etc. In addition, examples of actual compounds with these structures are given, along with their lattice parameters. All lattice parameters are stated in nm. Structure types are listed in the order in which they appear in the text, and are sequentially numbered. Most of the structural data in this appendix was extracted from the following sources:
• P. Villars, Pearson’s Handbook Desk Edition, ASM International, Materials Park, OH (1997);
• R.W.G. Wyckoff, Crystal Structures, John Wiley, New York (1963);
• C.S. Hurlbut and C. Klein, Manual of Mineralogy, 9th Edition, John Wiley and Sons, New York (1977).
When consulting the tables on the following pages, one must be aware of the fact that many compounds can have multiple crystal structures; it is always a good idea to consult the original sources listed above (and others) to verify that the correct structure is obtained. In particular, the examples of structures of a given structure type will often include metastable structures, or high temperature/high pressure phases; we refer the reader to the original sources for those details. Furthermore, atom coordinates provided in this appendix have been used with the sole purpose of creating structure visualizations; this means that sites with partial occupancy will show up in a structure drawing as fully occupied sites. The reader who wishes to compute x-ray powder patterns for any of these structures should consult the original citations to make sure that all site occupancies are properly accounted for. The compound names for intermetallics are listed in the same convention as in Pearson’s lists, namely an alphabetical ranking of all the elements in the compound, except for the prototype chemical formulas, for which we follow the list by J. Lima de Faria (J. Lima de Faria, Structural Classification and Notation, Chapter 1 in Intermetallic Compounds, Vol. 3, edited by J.H. Westbrook and R.L. Fleischer, John Wiley and Sons, New York (2002)). For instance, BiF3 is the prototype for the D03 structure, which has Mg 3Pr and AlFe 3 as example compounds; note that the elements are listed alphabetically, so that the AB3 compound is sometimes written as B3A. The only exception will be when the conventional prototype name is not in alphabetical order, for instance ZnS, in which case we do not change the order to SZn.
The present version of this structures appendix was completed on October 1, 2009; updates containing corrections will be posted as needed.
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