Synthesis and structure of Ba2LaAg5S6 and Ba2YAg5S6

Abstract

Abstract The new quaternary sulfides Ba2LaAg5S6 and Ba2YAg5S6 have been synthesized by the reaction among BaS, La2S3 or Y2S3, Ag, and S at 1000[unk]C. The crystal structure of Ba2LaAg5S6 has been determined by X-ray diffraction techniques. Crystal data: space group C2/m, M = 1145.3, Z = 2, a = 13.909(9), b = 4.229(3), c = 11.213(7) Å, β = 94.81(3)[unk] (T = 115 K), V = 657.2 Å3, R w(F2) = 0.191 for 1611 observations and 45 variables, R(F) = 0.069 for 1594 observations having F o 2 > 2σ(F o 2). The structure has a three-dimensional framework with channels that accommodate barium ions. The lanthanum atoms have octahedral coordination and silver atoms exhibit both tetrahedral and linear coordination. From Weissenberg photography Ba2YAg5S6 has cell dimensions at room temperature of a = 14.02(2), b = 4.18(1), c = 11.28(2) Å, β = 95.0(2)[unk] and appears to be isostructural with Ba2LaAg5S6.