Equiatomic rare earth rhodium plumbides RERhPb (RE=Y, La-Nd, Sm, Gd-Lu) with ZrNiAl-type structure

The equiatomic plumbides RERhPb (RE=Y, La-Nd, Sm, Gd-Lu) were synthesized by induction melting of the elements in sealed niobium ampoules. The samples were characterized by X-ray powder diffraction, confirming their ZrNiAl-type structure, space group P anti 62m. Four structures were refined from single-crystal X-ray diffractometer data: a=769.42(5), c=415.60(3) pm, wR=0.0415, 343 F² values, 15 variables for LaRhPb, a=767.91(6), c=369.37(4) pm, wR=0.0798, 284 F² values, 15 variables for ErRhPb, a=767.01(8), c=366.21(4) pm, wR=0.0380, 341 F² values, 15 variables for YbRhPb and a=766.9(1), c=363.42(6) pm, wR=0.0699, 290 F² values, 15 variables for LuRhPb. The RERhPb plumbides contain two crystallographically independent rhodium atoms, both in tricapped trigonal prismatic coordination: Rh1 rate at Pb₃RE₆ and Rh2 rate at RE₆Pb₃. Short Rh-Pb distances (277 and 284 pm in ErRhPb) are indicative of covalent Rh-Pb bonding. The crystal chemical details of the RERhPb series are compared with the silver plumbides REAgPb which show different transition metal-lead coloring. Temperature dependent magnetic susceptibility data show Pauli paramagnetism for YRhPb, LaRhPb and LuRhPb. An antiferromagnetic ground state below the Neel temperatures of 13.5, 21.0 and 6.9 K was found for PrRhPb, TbRhPb and DyRhPb, respectively. HoRhPb exhibits Curie-Weiss behavior in the observed temperature range.