Diagram of Solid-Phase Equilibria in the SnSe–Sb2Se3–Se System and Thermodynamic Properties of Tin Antimony Selenides

The SnSe–Sb2Se3–Se system was studied by the emf method and X-ray powder diffraction analysis, and the diagram of solid-phase equilibria at 400 K was constructed. The partial thermodynamic functions of SnSe in various phase regions of the studied system were calculated from the measured emf of concentration cells with respect to a SnSe electrode in the temperature range 300–450 K. These data together with the corresponding thermodynamic functions of SnSe and Sb2Se3 were used to calculate the partial molar functions of tin in alloys, and also the standard thermodynamic functions of formation and standard entropies of the compounds SnSe2, Sn2Sb6Se11, SnSb2Se4, and Sn2Sb2Se5.