The mineral Ag8GeS6 is the first compound of a wide class tetrahedrally close packed phases united by common name argyrodites. Ternary argyrodites are complex chalcogenides formed on basis multi- and single-charged cations. Structural polyhedrons tetrahedra multicharged cation chalcogens, cations occupy voids. Argyrodites belong to promising solid-state conductors thermoelectric materials. This...