Syntheses, crystal structure, and properties of Hf2Ni2In, Hf2Ni2Sn, Hf2Cu2In, and Hf2Pd2In with ordered Zr3Al2 type structure

摘要

Hf2Ni2In, Hf2Ni2Sn, Hf2Cu2In, and Hf2Pd2In were synthesized by reacting the elements in an are-melting furnace under argon and subsequent annealing at 970 K. They crystallize with an ordered Zr3Al2 type structure, space group P4(2)/mnm which was refined from single crystal X-ray data for Hf2Ni2In (a = 713.9(1) pm, c = 660.4(2) pm, wR2 = 0.0665, 513 F-2 values) and Hf2Ni2Sn (a = 703.1(1) pm, c = 676.1(2) pm, wR2 = 0.0423, 507 F-2 values) with 18 parameters for each refinement. The lattice constants for Hf2Cu2In and Hf2Pd2In are a = 715.5(1) pm, c = 677.0(1) pm and a = 742.6(1) pm, c = 679.4(2) pm, respectively. The structures may be considered as an intergrowth of distorted CsCl- and AlB2-like slabs. Magnetic susceptibility measurements indicate Pauli paramagnetism for Hf2Ni2In and Hf2Ni2Sn, which is consistent with the metallic conductivity observed for Hf2Ni2In. Sn-119 Mossbauer spectroscopy of Hf2Ni2Sn shows one signal with an isomer shift of delta = 1.59(1) mm/s subjected to quadrupole splitting of Delta E-q = 0.81(1) mm/s. [References: 14]