Geometric variations and electron localizations in intermetallics: PbFCl type compounds

Abstract The structural relations of the intermetallic compounds Cu 2 Sb, Mn 2 Sb, Fe 2 As, Mn 2 As, Cr 2 As, Sc 2 Sb as well as of YTiSi and ZrSiS, all adopting the PbFCl structure, are discussed. In the course of these investigations, the crystal structures of Mn 2 Sb, Mn 2 As and Fe 2 As have been redetermined and refined from single crystal data. Bandstructures have been calculated in the framework of Density Functional Theory. The bonding properties are compared on the basis of partial densities of states, of the Crystal Orbital Hamilton Population (COHP) and of the Electron Localization Function (ELF). The trend of the d electrons to become more localized with increasing number leads to different bonding conditions in the compounds discussed.