New binary antimonide Hf5Sb3 - Differences and similarities to the Zr antimonides

Hf5Sb3 can be prepared by are-melting of hafnium and previously synthesized HfSb2. It crystallizes like the high-temperature modification of Zr5Sb3 in the Y5Bi3 structure type, space group Pnma, Z=4, a=740.75(9) pm, b=871.8(1 ) pm, c=1073.6(1) pm, V=693.3(1) 10(6)pm(3). An antimonide analogous to the low-temperature form of Zr5Sb3 was not obtained during our investigations. In the structure of Hf5Sb3, the Hf atoms form a three-dimensional network with numerous short Hf-Hf contacts, including the Sb atoms in severely dist orted two- and three-capped trigonal prismatic voids. Calculations of the e lectronic structure, performed with the extended Huckel approximation as we ll as the TB-LMTO-ASA method, point to three-dimensional metallic propertie s of Hf5Sb3. (C) 1999 Elsevier Science S.A. All rights reserved.