To study the physicochemical interactions in the Tl2Se–CdSe–GeSe2 system, the triangulation of this quasi-ternary system was performed. The studied system Tl2Se–CdSe–GeSe2 on the limiting quasi-double sides, Tl2Se–GeSe2 and CdSe–GeSe2, is formed by four ternary chalcogenide compounds Tl4GeSe4, Tl2GeSe3, Tl2Ge2Se5, and Cd4GeSe6, and also by two quaternary compounds, Tl2CdGeSe4, and Tl2CdGe3Se8, which are formed inside the concentration triangle, of which the first two, ternary, and the last, quaternary, are formed congruently. The presence of five quasi-binary sections Tl4GeSe4–CdSe, Tl2GeSe3–CdSe, Tl2GeSe3–Tl2CdGe3Se8, Tl2CdGe3Se8–GeSe2, and Tl2CdGe3Se8–CdSe was established in this system, according to the results of triangulation. They divide the studied quasi-ternary system Tl2Se–CdSe–GeSe2 into five additional secondary subsystems: Tl2Se–CdSe–Tl4GeSe4, Tl4GeSe4–CdSe–Tl2GeSe3, Tl2GeSe3–CdSe–Tl2CdGe3Se8, Tl2GeSe3–Tl2CdGe3Se8–GeSe2, CdSe–Tl2CdGe3Se8–GeSe2. In this case, quasi-binary sections are formed based on the quaternary congruent Tl2CdGe3Se8 compound, considering stable binary and ternary compounds within the concentration interval of the existence of the quasi-ternary system Tl2Se–CdSe–GeSe2. Additionally, the crystal structure of the new quaternary chalcogenide Tl2CdGe3Se8 was calculated using the automated computer crystal-chemistry software package WinCSD. The formation of a new quaternary phase, Tl2CdGe3Se8, which crystallizes in the rhombic crystal lattice, SG P212121, was established in this system. Additionally, in this system, the formation of another quaternary compound, Tl2CdGeSe4, which crystallizes in the tetragonal system, SG I‑42m, is known.
Author Biographies
А. О. Selezen, National University of Water and Environmental Engineering, Rivne
PhD in Chemistry, Senior Lecturer
M. V. Moroz, National University of Water and Environmental Engineering, Rivne
Doctor of Chemical Sciences, Professor
L. V. Piskach, Lesya Ukrainka Volyn National University, Lutsk
