TERNARY TRANSITION-METAL ANTIMONIDES AND BISMUTHIDES WITH MGAGAS-TYPEAND FILLED NIAS-TYPE STRUCTURE

The 12 equiatomic ternary compounds NbFeSb, NbCoSb, TaCoSb, TRuSb (T = Ti, Zr, Hf, V, Nb, Ta), NbRhSb, ZrCoBi and ZrNiBi crystallize with th e face-centered cubic MgAgAs-type structure. The atom distribution on the three sites of this structure was established through Rietveld ref inements of X-ray data for VCoSb, NbFeSb, NbRuSb and ZrCoBi. At 750 de grees C VFeSb is isotypic with MgAgAs and at 850 degrees C it crystall izes with a filled NiAs-type structure. The latter structure was also found for a new modification of VNiSb. Magnetic susceptibility measure ments with a SQUID magnetometer indicate Pauli paramagnetism for TiFeS b, NbFeSb, TiCoSb, TiNiSb, VNiSb, TiRuSb, NbRuSb and NbRhSb.