The Family of LiCo6P4 Type Compounds – Trends in Electronic Structure and Chemical Bonding

Abstract Selected ternary compounds of the family of AT 6 X 4 (LiCo 6 P 4 ‐type) intermetallics were studied by ab initio methods with respect to their electronic structures and chemical bonding. The bonding characteristics highlight the role of the three‐dimensional [ T 6 X 4 ] polyanionic networks which, within the hexagonal channels, accommodate loosely bonded A cations. In alkali metal based compounds, when T is replaced by indium (e.g. in KIn 6 Au 4 ) the reverse occupancy leads to positively charged In (ca. +0.5) and negatively charged Au (ca. –0.9). Peculiar magnetic behavior is traced out whereby a magnetic order is identified only when T is a 3d element, which polarizes and induces a negative small moment on A (U) as in UCr 6 P 4 oppositely to CeRh 6 X 4 for X = Si, Ge.