Polymorphic transformations in Cu₂Se, Ag₂Se, AgCuSe and the role of partial cation-cation and anion-anion replacement in stabilizing their modifications

A review of studies of the crystalline structure of copper and silver chalcogenides is given. These materials have diverse physical properties making them promising in practical applications. Physical properties of crystals are determined by chemical composition, crystalline structure, and the influence of external conditions. In this work we carried out the analysis of published results on the crystalline structures of copper and silver chalcogenides at high and low temperatures. The inconsistency of published data on the crystal lattice parameters is noted. We also present our own results on the temperature dependence and the features of phase transitions in copper and silver chalcogenides with different composition.