Abstract
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.