Argyrodite family compounds and phases based on them are valuable ecologically friendly functional materials that exhibit a number of functional propreties, such as thermoelectric, photoelectric, optical, and other. On the other hand, having Cu⁺ and Ag⁺ ion conductivity, they are ionic conductors, and can be used as electrochemical sensors, electrodes, or electrolyte materials in solid-state batteries, displays, etc. In the present paper, phase relations in the Ag₈SiS₆–Ag₈SiTe₆ system were studied by differential thermal analysis and X-ray diffraction phase techniques and a T-x phase diagram was constructed. It is established that the system is quasi-binary and is characterized by the formation of a continuous series of substitutional solid solutions between Ag₈SiTe₆ and HT- Ag₈SiS₆ compounds. With the formation of solid solutions, the temperature of the polymorphic transition of the Ag₈SiS₆ decreases. This leads to the stabilization of the ion-conducting cubic phase in the range of compositions ³30 mol. % Ag₈SiTe₆ at room temperature and below. The homogeneity regions based on RT-Ag₈SiS₆ are 10 mol. %. According to XRD data, the crystal lattice parameters of the obtained solid solutions were calculated and a their linear dependence on the composition is shown

doi.org/10.32737/0005-2531-2023-2-169-177