Crystallography of Modular Materials

by Ferraris, Giovanni; Makovicky, Emil; Merlino, Stefano

• ISBN13: 9780198526643
• ISBN10: 0198526644
• Format: Hardcover
• Copyright: 2004-06-03
• Publisher: Oxford University Press

Summary

This is the first book to provide a comprehensive treatment of theories and applications in the rapidly expanding field of the crystallography of molecular materials. Molecules are the natural modules from which molecular crystalline structures are built. Most inorganic structures, however are infinite arrays of atoms and some kinds of surrogate modules, e.g. coordination polyhedra, are usually used to describe them. In recent years, the attention has been focused on complex modules as the basis for a systematic description of polytypes and homologous/polysomatic series (modular structures). This representation is applied to the modeling of unknown structures and understanding nanoscale defects and intergrowths in materials. He Order/Disorder (OD) theory is fundamental to developing a systematic theory of polytypism, dealing with those structures based on both ordered and disordered stacking of one or more layers. Twinning at both unit-cell and micro-scale, together with disorder, causes many problems, "demons", for computer-based methods of crystal structure determination. This book develops the theory of twinning with the inclusion of worked examples, converting the "demons" into useful indicators for unravelling crystal structure. In spite of the increasing use of the concepts of modular crystallography for characterizing, understanding and tailoring technological crystalline materials, this is the first book to offer a unified treatment of the results, which are spread across many different journals and original papers published over the last twenty years.

Table of Contents

1 Modular series-Principles and types	1	(126)
1.1 Brief outline	2	(1)
1.2 Hierarchical classification of structures	3	(2)
1.3 Short recapitulation of non-modular categories of similarity	5	(4)
1.4 Elements of modular description. Types of homologous/polysomatic series	9	(26)
1.5 Polysomatism	35	(6)
1.6 Chemical composition series	41	(1)
1.7 Variable-fit homologous series and series with a combined character	42	(15)
1.8 Merotype and plesiotype series	57	(53)
1.9 Ordered derivatives of solid solutions as modular structures	110	(3)
1.10 Principles of prediction of modular structures	113	(14)
2 OD structures	127	(80)
2.1 Introduction	127	(1)
2.2 OD character of wollastonite	128	(5)
2.3 OD structures of equivalent layers	133	(21)
2.4 Examples of OD families built up with equivalent layers	154	(26)
2.5 OD structures built up with M > 1 kinds of layers	180	(10)
2.6 Examples of OD structures consisting of two kinds of layers	190	(11)
2.7 List of other OD structures	201	(1)
Appendix 2.1 Table of monoclinic and orthorhombic OD-groupoid families	202	(2)
Appendix 2.2 Diffraction effects in wollastonite	204	(3)
3 Polytypes and polytype categories	207	(20)
3.1 Introduction	207	(20)
4 Application of modularity to structure description and modelling	227	(53)
4.1 Introduction	227	(1)
4.2 The perovskite module	228	(16)
4.3 Structures based on spinel modules	244	(6)
4.4 Slicing tetrahedral and octahedral layers	250	(19)
4.5 Miscellaneous modular structures	269	(9)
4.6 Some conclusions	278	(2)
5 Modularity at crystal scale - Twinning	280	(29)
5.1 Classification of twins	280	(10)
5.2 Consequences of twinning	290	(6)
5.3 Detwinning procedure	296	(3)
5.4 Examples	299	(8)
5.5 Conclusions	307	(2)
References	309	(52)
Subject Index	361