Synthesis, crystal structure, and electrical and magnetic properties of BaMo6Te6: A novel reduced molybdenum telluride containing infinite chains of trans-face shared Mo6 octahedra

Powder samples and single crystals of the new ternary compound BaMo6Te6 were obtained by solid state reaction. The structure was determined by single-crystal X-ray diffraction. BaMo6Te6 crystallizes in the hexagonal space group P6(3)/m (No. 176) with unit-cell parameters a =9.3941(2) angstrom, c=4.5848(1) angstrom and Z=1. Full-matrix least-squares refinement on F-2 using 452 independent reflections for 17 refinable parameters resulted in R1=0.0208 and wR2 = 0.0539. The structure consists of one-dimensional infinite chains of trans-face shared Mo-6 octahedra capped by Se atoms. These chains that are running along the c axis are separated from each other by nine-coordinate Ba atoms. Resistivity measurements on a single crystal indicated that the BaMo6Te6 compound is metallic down to 160 K and semiconductor below. Magnetic susceptibility measurements showed that BaMo6Te6 is weakly diamagnetic with no anomaly at the metal-semiconductor transition. (C) 2014 Elsevier Inc. All rights reserved.