Equiatomic rare earth (Ln) transition metal antimonides LnTSb (T=Rh, Ir) and bismuthides LnTBi (T=Rh, Ni, Pd, Pt)

摘要

Thirty-eight new ternary equiatomic antimonides and hismuthides were prepared by reaction of the elemental components at high temperatures, and the structures of four compounds were refined from single-crystal X-ray data. The antimonides LnRhSb (Ln = Sm, Gd-Tm) and LnIrSb (Ln = La-Nd, Sm, Gd-Tm) crystallize with the orthorhombic TiNiSi-type structure, which was refined for TbRhSb (a = 713.3(2) pm, b = 452.0(1) pm, c = 778.8(2) pm, R = 0.016 for 306 structure factors and 20 variable parameters) and SmIrSb (a 722.4(2) pm, b = 452.9(1) pm, c = 786.1(2) pm, R = 0.023 for 559 F values and 20 variables). The bismuthides LnRhBi (Ln = Pr-Sm) also crystallize with TiNiSi-type structure which was refined for SmRhBi (a = 728.0(2) pm, b 467.9(1) pm, c = 795.7(2) pm, R = 0.037 for 481 F values and 20 variables). The hexagonal ZrNiAl-type structure was established for the compounds LnRhBi (Ln = Gd-Er) through a structure refinement of DyRhBi (a = 757.9(2) pm, c = 392.6(1) pm, R = 0.026 for 423 F values and 14 variables). The bismuthides LnNiBi (Ln = Pr, Nd, Sm, Tb, Ho, Er), ScPdBi, LnPdBi (Ln = La, Er, Tin, Lu), and LaPtBi are isotypic with cubic MgAgAs. The atomic order for these equiatomic ternary bismuthides was determined for PrNiBi and LaPtBi from X-ray powder data. The structural chemistry of these compounds is briefly discussed. (C) 2002 Elsevier Science (USA). [References: 60]