Structure and Physical Properties of BaCu2Te2

BaCu2Te2 was synthesized at 690°C and its structure was determined via the Rietveld refinement method using powder X-ray diffraction with Rp/wRp(%)=4.01/5.36. BaCu2Te2 crystallizes in the orthorhombic space group Pnma (No. 62) with Z=4 and a=10.1244(5) ?, b=4.4577(3) ?, c=11.4642(6) ?, V=517.85(5) ?3. It adopts the same structure type as 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.