Electron diffraction study of phase transformations of the compound CuSe

The transformations of the compound CuSe were investigated. At temperatures below 350°C the consecutive phase transitions CuSe→Cu2−xSe→Cu2Se were observed. Above 350°C decomposition of the CuSe into two phases, Cu2Se and an f.c.c. phase with a=5.63Å, takes place. It was determined that the range of the lattice parameter a of the f.c.c. phase Cu2−xSe is from 5.68 to 5.75Å and the existence ranges of the phases observed were evaluated. It was shown that the f.c.c. phase with a=5.63Å is an independent phase.