Thermal stability of the CuCrSe2.

The crystal structure of CuCrSe 2 in the temperature range 25 - 1000 °C was studied by synchrotron X-ray diffraction. It was found that heating leads to the decomposition of stoichiometric CuCrSe 2 into two phases of composition CuCr 2 Se 4 and Cu 1+x CrSe 2 with increased Cu content. It was found that copper enrichment of CuCrSe 2 during heating occurs up to the temperature of 800 °C and the limiting composition is close to the compound Cu 4 Cr 3 Se 6. It was found that heating equalizes the copper distribution at the α- and β-tetrahedrally coordinated chalcogen positions, but full equality of their occupancy at temperatures up to 1000 °C was not achieved. The low temperature limit of CuCr 2 Se 4 excretion was established to be approximately 300 °C and the decomposition temperature of CuCr 2 Se 4 to be approximately 1050 °C. Fragments of the crystal structure CuCrSe 2 for P-3m1 (left panel), R-3m (central panel) and R3m (right panel) space group. [Display omitted] • The synthesis of CuCrSe 2 has been performed. • A study of the crystal structure during in-situ heating was performed. • The region of phase instability has been established. • The defect type of CuCrSe 2 is defined. • A fragment of the phase diagram is proposed. [ABSTRACT FROM AUTHOR]