Synthesis and characterisation of the compound CoSbS

Description

In the search for new intermetallic materials with high thermoelectric performances, the Co–Sb–S ternary system has been explored and polycrystalline CoSbS samples have been prepared by a vapour phase technique starting from the pure elements. The crystal cell of CoSbS belongs to the Pbca space group and shows an orthorhombic structural arrangement with the following lattice parameters: a = 5.8341(2) A ° ; b = 5.9477(2) A ° , and c = 11.6540(4) A ° . The structure belongs to the pyrite–marcasite family, as Co forms tilted corner- and edge-sharing octahedra with three Sb and three S atoms. Scanning electronic microscopy (SEM), electron-probe microanalysis (EPMA) and X-ray powder diffraction were used to investigate the microstructure and to carry out the structural analysis; the crystal structure was refined by the Rietveld method using the DBWS-9807 program. The thermal stability of CoSbS was investigated referring to the ternary Co–S–Sb phase diagram and by differential thermal analysis (DTA) measurements. Thermoelectric power measurements at room temperature were also performed by a home-made instrument.

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