SYNTHESES, CRYSTAL-STRUCTURE, AND PROPERTIES OF HF2NI2IN, HF2NI2SN, HF2CU2IN, AND HF2PD2IN WITH ORDERED ZR3AL2 TYPE-STRUCTURE

Hf2Ni2In, Hf2Ni2Sn, Hf2Cu2In, and Hf2Pd2In were synthesized by reactin g the elements in an are-melting furnace under argon and subsequent an nealing at 970 K. They crystallize with an ordered Zr3Al2 type structu re, 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 = 0.0 423, 507 F-2 values) with 18 parameters for each refinement. The latti ce 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 structur es may be considered as an intergrowth of distorted CsCl- and AlB2-lik e slabs. Magnetic susceptibility measurements indicate Pauli paramagne tism for Hf2Ni2In and Hf2Ni2Sn, which is consistent with the metallic conductivity observed for Hf2Ni2In. Sn-119 Mossbauer spectroscopy of H f2Ni2Sn 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.