Phase relations in the system sulfur—Silver and the transitions in silver sulfide

Abstract

This paper presents the melting relations for the entire system sulfursilver, together with a study of the transition behavior of silver sulfide. Silver sulfide melts at 838±2°C and undergoes two transitions in the solid state, each of which occurs at variable temperatures over a limited range of composition. The mean temperatures for the lower transition (Ag 2 S III=Ag 2 S II) are 177.8°C in sulfur‐rich and 176.3°C for silver‐rich preparations; for the upper transition (Ag 2 S II=Ag 2 S I) they are, respectively, 622°C and 586°C. A discussion is given of a possible mechanism for the incorporation of a limited excess of sulfur or silver into the lattice, as bised on the semi‐conducting properties of the substance and lattice disorder The melts of silver sulfide form two liquid layers with sulfur‐rich melts at 740°C, and with silver‐rich melts at 906°C. The eutectic with sulfur is at 119.3°C, and with silver, at 804°C.