Silver - Arsenic - Sulfur

Rainer Schmid-Fetzer

Introduction

The ternary compound Ag₃AsS₃(h) (proustite) has been synthesized in evacuated silica capsules and a congruent melting point has been determined by thermal analysis or DTA as ranging from 480 to 495°C [12Jae, 57Wer, 66Rol, 68Weh, 70Kov, 70Rol2, 71Kov, 77Fed, 77Ily]. A hexagonal/rhombohedral lattice was detected by X-ray studies on synthetic powdered material [58Wer, 63Tou, 70Rol1] and also in a more detailed study using a natural single crystal [66Eng]. Lattice parameters obtained from Ag₃AsS₃(h) are in excellent agreement with those extrapolated from the Ag₃AsS₃-Ag₃SbS₃ complete solid solution [63Tou]. The monoclinic room temperature polymorph Ag₃AsS₃(r) (xanthoconite) was also synthesized [66Hal, 66Rol, 70Rol2...