ATOMIC-ENVIRONMENT CLASSIFICATION OF THE CUBIC INTERMETALLIC STRUCTURE TYPES

In this paper we give a complete description of the geometrical atomic environments found in the structure types of the cubic intermetallic compounds. Our analysis of 172 structure types which have been reported in the literature showed that 128 are geometrically possible, while the remaining 44 structure types have improbable interatomic distances. We have classified all point sets of these structure types in terms of the realized geometrical atomic environments and give rules for the analysis as well as the classification. In our systematic and comprehensive analysis of the cubic structure types we have verified all known relationships between these structure types, but the analysis also revealed new non-trivial relationships. In addition, we observed that 21 atomic environment types are strongly preferred. Out of 13 917 point sets investigated, 12 790 (92%) belong to one of those 21 atomic environment types. Of the 5521 compounds crystallizing into one of the 128 structure types, 46% belong to a single-environment group (structures in which all atoms have the same type of environment), 37% combine two environment types, 9% have three environments and the rest (8%) have four or more environments.