PREPARATION AND CRYSTAL-STRUCTURE OF NA3AUS2, A THIOAURATE WITH ISOLATED ANIONS

The compound Na//3AuS//2 was prepared by the reaction of a stoichiometric mixture of Na//2S, gold and sulfur at 600 degree C. Transparent, colorless crystals were obtained by slowly cooling the melt. The crystal structure was determined from four-circle diffractometer data. Na//3AuS//2 crystallizes in a new structure type, which is characterized by discrete linear left bracket S-Au-S right bracket **3** minus -anions, oriented along left bracket 001 right bracket . The sodium cations are surrounded by four sulfur atoms in a distorted tetrahedral coordination. The structure of Na//3AuS//2 can be derived from a bcc packing of sulfur atoms, which is described as a space-filling arrangement of distorted sulfur tetrahedra.