Thermodynamic Study of Siver—Tin Selenides by the EMF Method with Ag4RbI5 Solid Electrolyte

Resumo

The system Ag-Sn-Se in the region of Ag₂Se-SnSe-Se composition is studied by measuring EMF of cells with Ag₄RbI₅ solid electrolyte in the temperature interval of 300–450 K. Based on the results of EMF measurements, the temperature of Ag₈SnSe₆ polymorphous transition (355 K) is determined and the partial molar functions of silver in certain phase regions of this system are calculated. Standard thermodynamic functions of formation and standard entropies are estimated for ternary phases AgSnSe₂, Ag_0.84Sn_1.16Se₂, and two modifications of Ag₈SnSe₆ and also thermodynamic functions of Ag₈SnSe₆ polymorphous transition.