Thermal stability of the CuCrSe2

The crystal structure of CuCrSe2 in the temperature range 25 -1000 degrees C was studied by synchrotron X-ray diffraction. It was found that heating leads to the decomposition of stoichiometric CuCrSe2 into two phases of composition CuCr2Se4 and Cu1}xCrSe2 with increased Cu content. It was found that copper enrichment of CuCrSe2 during heating occurs up to the temperature of 800 degrees C and the limiting composition is close to the compound Cu4Cr3Se6. It was found that heating equalizes the copper distribution at the alpha-and beta-tetrahedrally coordinated chalcogen positions, but full equality of their occupancy at temperatures up to 1000 degrees C was not achieved. The low temperature limit of CuCr2Se4 excretion was established to be approximately 300 degrees C and the decomposition temperature of CuCr2Se4 to be approximately 1050 degrees C.