Ternary intermetallics Hf(13.0)Ni(40.8)Ga(30.9) and Zr(13.0)Ni(40.6)Ga(31.0)

Abstract

Ternary compounds Hf(13).(0)Ni(40.8)Ga(30.9) and Zr(13.0)Ni(40.6)Ga(31.0) were synthesized from the pure elements in arc-melting reactions; their structures were characterized through X-ray diffraction of single crystals. Each compound adopts a hexagonal structure of type Y(13)Pd(40)Sn(31) and crystallizes in space group P6/mmm (No. 191). The cell parameters of Hf(13.0)Ni(40.8)Ga(30.9) are a = 17.895(3)angstrom; c = 8.2434(16)angstrom; V=2286.0(6) angstrom(3); R(1)/wR(2)= 0.0299/0.0598. The cell parameters of Zr(13.0)Ni(40.6)Ga(31.0) are a= 17.964(3) angstrom; c = 8.2757(17) angstrom; V= 2312.7(7) angstrom(3); R(1)/wR(2) = 0.0348/0.0686. These structures comprise polyhedra with diverse coordination numbers - Hf 12-15, Ni and Ga 6-12. Analysis of the structures reveals layer frameworks based on structures of type CaCus, accompanied with atomic substitution and elimination on the layers and decreased values of the concentration of valence electrons. Calculated electronic structures reveal a strong contribution from a Ni-Ga interaction and the characteristics of a polar interrnetallic phase. (C) 2011 Elsevier Ltd. All rights reserved.