Isothermal section of the Ag 2S–PbS–GeS 2 system at 300 K and the crystal structure of Ag 2PbGeS 4

Abstract

The isothermal section of the Ag 2S–PbS–GeS 2 system at room temperature was investigated by XRD. The existence of two quaternary compounds, Ag 2PbGeS 4 and Ag 0.5Pb 1.75GeS 4, was confirmed, and the phase equilibria between the binary system components and the ternary and the quaternary compounds were determined. The crystal structure of Ag 2PbGeS 4 was studied using the single crystal X-ray diffraction. It was established that Ag 2PbGeS 4 crystallizes in an own structural type in non-centrosymmetric space group Ama2 with the lattice parameters a = 1.02390(4) nm, b = 1.02587(5) nm, c = 0.67701(3) nm.