This book contains the contributions of 13 well known specialists in the field of solid state chemistry who had been invited as lecturers at a 1992 NATO Advanced Study Institute in Erice, Sicily. The chapters of a more general character concern the use of the space group - subgroup relationships for the recognition of structure families, the crystal chemical formulae (which is a way of denoting simple crystal chemical information in a condensed form), the concepts of atom co-ordination, atom volume and charge transfer and the physicist's view of the bond strength in the solid which is measured by the crystal orbital overlap population. It is demonstrated for the case of ionic compounds that the bond valence method is superior to the old sum-of-radii method for the prediction of interatomic distances. Simple valence electron rules can be applied fto compounds with tetrahedral anion complexes. These rules allow one not only to make predictions on expected structural features of unknown compounds, but also to point out inconsistencies between the reported structure and composition of known compounds. Detailed accounts are presented on the crystal chemistry of the superconducting copper oxides, the sulfosalts, the metal cluster compounds, the silicates and the transition metal borides and related compounds. In the case of intermetalic compounds the intergrowth concept is found to be very useful for an "understanding" of complicated atom arrangements. At the end of each chapter there can be found problems and their solutions. This makes it possible for (advanced) undergraduates in chemistry, physics, metallurgy, materials science and mineralogy to be able to profit from a study of this book.

The study of crystal structures has had an ever increasing impact on many fields of science such as physics, chemistry, biology, materials science, medicine, pharmacy, metallurgy, mineralogy and geology. Particularly, with the advent of direct methods of structure determination, the data on crystal structures are accumulating at an unbelievable pace and it becomes more and more difficult to oversee this wealth of data. A crude rationalization of the structures of organic compounds and the atom coordinations can be made with the well-known Kekule model, however, no such generally applicable model exists for the structures of inorganiC and particularly intermetallic compounds. There is a need to rationalize the inorganic crystal structures, to find better ways of describing them, of denoting the geometrical relationships between them, of elucidating the electronic factors and of explaining the bonding between the atoms with the aim of not only having a better understanding of the known structures, but also of predicting structural features of new compounds.

TYPIX is a critical compilation of crystallographic data prepared by E. Parthe at the University of Geneva. It contains over 3200 compounds representative of the structure types found among inorganic compounds. This work contains condensed crystal chemical information about individual structure types as well as an extensive chapter on the crystal chemistry of particular structure families. The aim of the compilation is to clarify and classify published data for intermetallic and other inorganic structures (types found exclusively with halides or oxides are only included for a few special cases). It provides a tool for additional crystal chemical studies and the development of new materials."

The crystaLLographer usuaLLy needs, as a compLement to his experimentaL work, a smaLL structure data compiLation. My first, some 25 years ago, was a hand-written List of structure types containing space group, unit ceLL data and positionaL atom coordinates. Some 20 years ago, when computers had become a more easiLy accessibLe tooL, a smaLL computer test fiLe was created with the help of Dr. Jan Portheine, which was LabeLLed TYPIX. Assisted by Dr. KLaus Yvon I inserted in the fiLe the somewhat more than 200 inorganic crystaL structure types which were of interest for our research or with which I was famiLiar from my previous experimentaL crystaL structure studies on intermetalLics and tetrahedraL structure compounds. We soon stopped our work on TYPIX because we reaLized that simpLy storing structure data copied from the Literature did not serve our finaL objective. I had, for exampLe, Listed the structures of certain isotypic compounds as separate distinct structure types because, due to a different setting or description given in the originaL Literature, I missed their isotypism. In other cases, with good Luck, I found the isotypism and succeeded in correctLy transforming one description to the other but then did not know which of the different but equivaLent descriptions I shouLd retain in my data coLLection.