RERhZn (RE = Y, Sm, Gd–Lu) compounds with TiNiSi type structure – Synthesis and magnetic properties

The TiNiSi type intermetallic compounds RERhZn (RE = Y, Sm, Gd–Lu) were synthesized by induction melting of the elements in sealed tantalum ampoules. They were characterized by X-ray powder diffraction. Five structures were refined from single crystal X-ray diffractometer data: Pnma, Z = 4, a = 699.7(2), b = 405.6(2), c = 816.9(2) pm, wR2 = 0.038, 628 F2 values for SmRhZn, a = 696.1(2), b = 405.6(1), c = 811.9(3) pm, wR2 = 0.028, 886 F2 values for GdRhZn, a = 692.8(1), b = 403.0(1), c = 809.5(2) pm, wR2 = 0.039, 562 F2 values, for TbRhZn, a = 690.6(3), b = 401.50(9), c = 808.2(2) pm, wR2 = 0.036, 763 F2 values, for DyRhZn, and a = 688.6(5), b = 399.6(4), c = 808.3(7) pm, wR2 = 0.048, 546 F2 values for HoRhZn with 20 variables for each refinement. The rhodium atoms have coordination number 9 (5 RE + 4 Zn atoms) in the form of a tricapped trigonal prism. Together the rhodium and zinc atoms build up three-dimensional [RhZn] networks with short Rh–Zn (263–269 pm in GdRhZn) and Zn–Zn (296 pm in GdRhZn) distances. The gadolinium atoms bind to the [RhZn] network by Gd–Rh bonds (292–294 pm). Magnetic susceptibility measurements show Pauli paramagnetism for YRhZn and van Vleck paramagnetism for SmRhZn. The remaining RERhZn compounds are Curie–Weiss paramagnets which show magnetic ordering at low temperatures.

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