Accession Number : AD0257395

Title :   PREPARATION AND PROPERTIES OF THERMOELECTRIC MATERIALS

Corporate Author : COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL PARIS (FRANCE)

Report Date : APR 1961

Pagination or Media Count : 1

Abstract : Molybdenum telluride, MoTe2, was prepared by chemical transport reaction. Pure Mo and Te are placed in a horizontal quartz tube at about 800 C. Deposition is accomplished at about 750 C wtih Br as the transport agent. The temperature gradient is important, small variations in temperature stopping the transport phenomenon and sometimes causing wide and thin crystals, 1 to 2 sq cm inAREA, TO GRO ON THE Mo; the crystals are probably Mo2Te3. The specific gravity of MoTe2 is 8.5; the crystals are soft and make black marks on paper. Standard X-ray analysis on single crystals of MoTe2 was performed with the rotating crystal method (Cu K-alpha radiation). The first lattice constant of the hexagonal system was expressed by the equation a equals 3.52 + or - 0.05 angstrom units. With the axis of rotation parallel to the c axis, c equals 14 + or - 0.2 angstroms. The following compounds are also being prepared: MoSe2, WSe2, and WTe2.

Descriptors :   *MOLYBDENUM COMPOUNDS, *SEMICONDUCTORS, *TELLURIDES, *THERMOELECTRICITY, BROMINE, ELECTRICAL PROPERTIES, PHYSICAL PROPERTIES, PREPARATION, SELENIDES, SINGLE CRYSTALS, SYNTHESIS, TUNGSTEN COMPOUNDS

Distribution Statement : APPROVED FOR PUBLIC RELEASE