On the existence of ZrAs 2 and ternary extension Zr(Ge xAs 1− x)As (0 ≤ x ≤ 0.4)

Abstract

Zirconium diarsenide, ZrAs 2, has been established to be a genuine binary phase that is strictly stoichiometric. At 900 °C, it supports extensive solubility of Ge to form the ternary extension Zr(Ge x As 1− x )As (0 ≤ x ≤ 0.4). The crystal structures of ZrAs 2 and Zr(Ge 0.33(6)As 0.67)As were determined by single-crystal X-ray diffraction (orthorhombic PbCl 2-type, space group Pnma, Z = 4), with one of the two possible anion sites being preferentially occupied by the Ge atoms. X-ray photoelectron spectra and band structure calculations confirmed that the Ge and As atoms are anionic in character and that the substitution of Ge for As is driven by a depopulation of anion–anion antibonding states. ZrGe 0.3As 1.7 exhibits metallic behaviour and temperature-independent Pauli paramagnetism.