Synthesis, and Crystal and Electronic Structures, of the Titanium-Rich Bismuthides AE3Ti8Bi10 ( AE = Sr, Ba, Eu).

Three isotypic compounds with the chemical formula AE3Ti8Bi10 ( AE = Sr, Ba, Eu) have been obtained via both high-temperature solid state and flux growth reactions. Their crystal structure, representing a new type (space group P63/ mmc, Pearson symbol hP42), features an open framework composed of interlinked TiBi5 square pyramids and TiBi6 octahedra. The Ti-Bi substructure is penetrated by infinite columns of face-sharing AE6 polyhedra centered by Bi atoms. First-principle calculations and physical property measurements indicate metallic behavior and absence of localized magnetic moments on the Ti atoms. Analysis of the chemical bonding reveals strong Ti-Bi and Ti-Ti bonds. The latter demonstrate classic two-center, as well as multicenter, interactions.