Structure and physical properties of BaCu2Te2

BaCu2Te2 was synthesized at 690 degreesC and its structure was determined via the Rietveld refinement method using powder X-ray diffraction with R-p/wR(p)(%) = 4.01/5.36. BaCu2Te2 crystallizes in the orthorhombic space group Pnma (No. 62) with Z = 4 and a = 10.1244(5) Angstrom, b = 4.4577(3) Angstrom, c = 11.4642(6) Angstrom, V = 517.85(5) Angstrom (3). it adopts the same structure type as alpha -BaCu2S2/BaCu2Se2/BaZn2Sb2. In BaCu2Te2, distorted CuTe4 tetrahedra connect with one another by edge-sharing and corner-sharing to build up a three-dimensional framework. There is no structural resemblance between BaCu2Te2 and Cu2Te (P6/mmm), but remarkably, the BaCu2Te2 framework is topologically identical to the net found in the mineral feldspar, Electrical property measurements on a sintered pellet indicate that it is a p-type degenerate semiconductor. An anomaly was observed in the variation of electrical resistivity as a function of temperature near 65 K. (C) 2001 Academic Press.