Phase Equilibria in the Ag2Se–Cu2SnSe3 and Ag8SnSe6–Cu2SnSe3 Systems

• Published in: Russian journal of inorganic chemistry 2020-12, Vol.65 (12), p.1899-1904
• Main Authors: Rzaguliev, V. A., Mamedov, A. N., Kerimli, O. Sh, Mamedov, Sh. G.
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Physicochemical Analysis of Inorganic Systems
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S003602362012013X

The phase formation in the sections Ag 2 Se–Cu 2 SnSe 3 and Ag 8 SnSe 6 –Cu 2 SnSe 3 of the quasi-ternary system Ag 2 Se–SnSe 2 –Cu 2 Sе was studied for the first time by differential thermal analysis (with thermodynamic calculations), X-ray powder diffraction analysis, and microstructural analysis and also by microhardness and density measurements. No new quaternary compounds were detected. It was determined that both sections are quasi-binary and are of simple eutectic type with limited solubility based on the initial selenides. The coordinates of the eutectic points are (40 mol % Ag 2 Se, 910 K) and (50 mol % Ag 8 SnSe 6 , 780 K). The solubility based on Cu 2 SnSe 3 was 10 mol % Ag 2 Se in the system Ag 2 Se–Cu 2 SnSe 3 and 15 mol % Ag 8 SnSe 6 in the system Ag 8 SnSe 6 –Cu 2 SnSe 3 . Single crystals of the compound Cu 2 SnSe 3 and the solid solutions (Cu 2 SnSe 3 ) 1 – х (Ag 8 SnSe 6 ) х ( х = 0.02–0.15) were grown by the Bridgman–Stockbarger directional crystallization method. It was found that these solutions crystallize in the monoclinic system, and the unit cell parameters increase with increasing Ag 8 SnSe 6 content: а = 6.968–6.985 Å, b = 12.051–12.078 Å, с = 6.945–6.968 Å, β = 109.20°–109.30°, space group Сс , Z = 4, and ρ = 5.75–5.86 g/cm 3 .