High-pressure, high-temperature study of GeS2 and GeSe2

• Published in: Inorganic materials Vol. 50; no. 8; pp. 768 - 774
• Main Authors: Kulikova, L. F., Lityagina, L. M., Zibrov, I. P., Dyuzheva, T. I., Nikolaev, N. A., Brazhkin, V. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.08.2014
• Subjects: Chemistry; Chemistry and Materials Science; Industrial Chemistry/Chemical Engineering; Inorganic Chemistry; Materials Science; Inorganic Material; General Structure Analysis System; High Pressure Phase; Previous Experimental Data; High Temperature Study
• ISSN: 0020-1685; 1608-3172
• DOI: 10.1134/S002016851408010X

Phase transitions of the GeX 2 (X = S, Se) dichalcogenides have been studied at pressures of up to p ≃ 8 GPa and temperatures from 675 to 1375 K, and portions of their p - T phase diagrams have been constructed using our and previous experimental data. The crystal structure of the GeS 2 -III phase has been refined by the Rietveld method (HgI 2 structure, P 4 2 / nmc , a = 3.46906(2) Å, c = 10.9745(1) Å, Z = 2, D x = 3.438 g/cm 3 , R = 0.06). GeSe 2 -III crystals have been grown for the first time at p ≃ 7 GPa in the temperature range 875–1275 K. The unit-cell parameters of GeSe 2 -III (hex) are a = 6.468 ± 0.004 Å and c = 24.49 ± 0.10 Å ( D meas = 5.16 g/cm 3 , D x = 5.18 g/cm 3 , Z = 12).