NEW COMPOUNDS WITH MGAGAS-TYPE STRUCTURE - NBIRSN AND NBIRSB

NbIrSn and NbIrSb crystallize in a cubic MEAgAs-type structure with la ttice parameters of 617.76(2) and 614.97(2) pm, respectively. Both com pounds exhibit incongruent melting behaviour. NbIrSn is a p-type semic onductor with an energy gap of 0.28 eV. At room temperature, it has a Seebeck coefficient of +176 mu V K-1 and a resistivity of 1.1 Omega cm . NbIrSb is metallic with S = +3.5 mu V K-1 and rho = 1.5 x 10(-3) Ome ga cm at room temperature. The formation of the solid solutions NbIrSn 1-xSbx has been confirmed.