Ternary rare earth-rich nickel cadmium compounds RE ₁₄ Ni ₃ Cd ₃ ( RE = Dy–Tm, Lu)

The rare earth-rich intermetallic cadmium compounds RE 14 Ni 3 Cd 3 ( RE = Dy–Tm, Lu) were synthesized by induction melting of the elements in sealed tantalum ampoules, followed by annealing in sealed quartz tubes in muffle furnaces. The polycrystalline samples were characterized by powder X-ray diffraction, confirming isotypism with Gd 14 Co 3 In 2.7 , space group P 4 2 / nmc . The structures of the holmium and lutetium compound were refined from single-crystal X-ray diffractometer data: a = 945.03(3), c = 2,275.64(7) pm, w R 2 = 0.0316, 2800 F 2 values, 64 variables for Ho 14 Ni 3.70(1) Cd 2.27(1) and a = 929.79(3), c = 2,237.53(6) pm, w R 2 = 0.0537, 1315 F 2 values, 63 variables for Lu 14 Ni 3.69(3) Cd 2.31 . The striking structural feature of these cadmium phases is the formation of small defects on one 8 g nickel site and Cd/Ni mixing on the Wyckoff position 4 c . The complete RE 14 Ni 3 Cd 3 structures can be described by a condensation of tricapped trigonal prisms around the nickel and icosahedra around the cadmium atoms. Temperature dependent magnetic susceptibility studies have revealed Curie-Weiss paramagnetism for Ho 14 Ni 3 Cd 3 , Er 14 Ni 3 Cd 3 and Tm 14 Ni 3 Cd 3 with antiferromagnetic transitions in the low-temperature regime ( T N = 13.1(1), 8.6(1) and 3.6(1) K for RE = Ho, Er and Tm, respectively).