Flux Growth, Crystal Structures, and Electronic Properties of the Ternary Intermetallic Compounds Ca 3 Pd 4 Bi 8 and Ca 3 Pt 4 Bi 8 .

Reaction of the elements yielded Ca 3 Pt 4 Bi 8 and CaPtBi, which are, to the best of our knowledge, the first reported ternary Ca-Pt-Bi compounds. The compounds crystallize isostructural to the Pd analogs Ca 3 Pd 4 Bi 8 (own structure type) and CaPdBi (TiNiSi structure type), respectively. Employing a multistep temperature treatment allows for the growth of mm-sized single crystals of Ca 3 Pd 4 Bi 8 and Ca 3 Pt 4 Bi 8 from a Bi self-flux. Their crystal structures can be visualized as consisting of a three-dimensional extended polyanion [M 4 Bi 8 ] 6- (M = Pd, Pt), composed of interlinked M-Bi chains propagating along the c direction, and Ca 2+ cations residing in one-dimensional channels between the chains. First-principles calculations reveal quasi-one-dimensional electronic behavior with reduced effective electron masses along [001]. Bader analysis points to a strong anionic character of the M species (M = Pd, Pt) in Ca 3 M 4 Bi 8 . Thus, it is more appropriate to address the compounds Ca 3 Pd 4 Bi 8 and Ca 3 Pt 4 Bi 8 as a palladide and platinide, respectively. Magnetization measurements indicate diamagnetic behavior with no indications for superconductivity down to 2 K. Electrical resistivity data are consistent with metallic behavior and suggest predominant electron-phonon scattering.