Crystal structure of Сu2–m Te (m = 0.25)

Abstract

The Сu2Te compound has been synthesized by alloying Сu and Te taken in stoichiometric ratios. A Сu2Te 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 а = 8.328(1) A, с = 7.196(1) A, V = 432.2(1) A3, sp. gr. \(P\overline 3 m1\), Z = 8. The crystal structure is determined and the sample composition Сu2–mTe (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.