Crystal structure of Cu2-m Te (m=0.25)

摘要

The Cu2Te compound has been synthesized by alloying Cu and Te taken in stoichiometric ratios. A Cu2Te sample has been homogenized by annealing at 773 K for 100 h. A pure copper phase in the form of thin filaments is found to segregate from the synthesized product (4 g) by the end of annealing. It is established by X-ray diffraction analysis that the copper-deficient sample is crystallized into the trigonal system with lattice parameters a = 8.328(1) angstrom, N = 7.196(1) angstrom, V = 432.2(1) angstrom(3), sp. gr. P (3) over bar ml, Z = 8. The crystal structure is determined and the sample composition Cu2-m Te (m = 0.25) is refined by the Rietveld method. The three independent copper atoms in the lattice are found to have different coordination numbers: 3, 4, and 5.