Thallous chloride—thallous sulphide phase diagram

Abstract

The phase diagram of the TlCl + Tl₂S system has been determined by the method of cooling curves. Calculations of thermodynamic properties of the liquid have been made using the cryoscopic data, together with an analysis of the AgCl + Ag₂S molten system for comparison, using recently published values. The two systems are found to be describable using the “Quadratic Formalism” of Darken, the structure of the melts apparently changing from that of the halide to that of the chalcogenide over very narrow transition zones. The thallium transition region lies at greater sulphide concentration than the silver one.