New quinternary selenides: Syntheses, characterizations, and electronic structure calculations

Abstract

Five quintemary selenides, Sr2.63Y0.37Ge0.63Sb2.32Se8 (I), Sr2.6La0.37Ge0.63Sb2.37Se8 (II) Sr2.71La0.29Sn0.77- Bi2.23Se8 (III), Ba2.67La0.33Sn0.67Sb2.33Se8 (IV), and Ba2.67La0.33Sn0.67Bi2.33Se8 (V), were synthesized by solid-state reaction in fused silica tubes. These compounds are isostructural and crystallize in the Sr3GeSb2Se8 structural-type, which belongs to the orthorhombic space group Pnma (no. 62). Three structural units, (1)(infinity)[MSe3], (1)(infinity)[M4Se10] (M=Tt, Pn) and M' (M'=groups II and III element), comprise the entire one-dimensional structure, separated by M'. Measurements of electronic resistivity and diffused reflectance suggest that IV and V have semiconducting properties. Electronic structure calculations confirm the site preferences of Sr/La element discovered by crystal structure refinement. (C) 2013 Elsevier Inc. All rights reserved.