Nonstoichiometric Cu2 Research Articles

X-ray investigation of copper selenides Cu2−xSe (2.00≥2-x≥1.72)

The lattice parameters and the linear coefficient of the lattice thermal expansion of f.c.c. β-Cu2−xSe (1.86 ≥ 2−x ≥ 1.72) were determined by means of the Debye–Scherrer X-ray diffraction technique in the temperature range 25–336°C. The concentration and temperature dependence of the coefficient of thermal expansion are discussed. In addition the equilibrium phase diagram of the Cu–Se system in the region of a non-stoichiometric Cu2−xSe compound (2.00 ≥2−x ≥1.72) was redetermined, with special consideration of the homogeneity range of the f.c.c. β-Cu2−xSe, and compared with previously published results.