BaAg2S2, a thioargentate with the CaAl2Si2-type structure

BaAg2S2 could be obtained as crystalline powder by the reaction of barium-bis[dicyanoargentate(I)] in a stream of hydrogensulfid at 500 degrees C. Single crystals grew at 480 degrees C in an evacuated glass ampoule filled with a flux of potassium thiocyanate and powdery BaAg2S2 as solid. BaAg2S2 crystallises in the trigonal CaAl2Si2-typ structure, a = 4.386(1) Angstrom, c = 7.194(2) Angstrom, space group P3m1, Z = 1. The structure was determined from four-circle diffractometer data. The silver-sulphur distances are discussed with respect to the corresponding distances of the hitherto known alkaline earth-transition metal pnictides, also crystallizing in the CaAl2Si2-typ structure.