Ternaire argent-germanium-sulfure. Quasibinaire disulfure de germanium - sulfure d'argent. Conductivite electrique du verre le plus riche en argent

We establish that this phase diagram has only one compound Ag8GeS6 (congruent melting at 950°C) surrounded by two eutectics (820°C, n = 0.97 (n = AgAg+Ge) and 470°C, n = 0.42). Ag8GeS6 is dimorphic; transition temperature: 215°C. Low temperature form is orthorhombic (argyrodyte), high temperature form is cubic, centered faces. A glass forming domain exists from n = 0 to n = 0.67 (Tg ≈ 250°C, Tc ≈ 325°C). Electric conductivity is made by the impedance method for glass richer in silver (GeS2-Ag2S). The conductivity is ionic type. Study of the ternary Ag-Ge-S diagram establishes that the GeS2-Ag2S section is quasi-binary.