Metal-rich polyantimonides: internal competition between M–M and Sb–Sb and heteroatomic M–Sb interactions in (Zr,V)13Sb10 and (Zr,V)11Sb8 (M = Zr,V)

Abstract

The title compounds are accessible by arc-melting of suitable mixtures of Zr, V and ZrSb ₂ . Their crystal structures were determined via single crystal measurements on an IPDS diffractometer. Depending on the M∶Sb ratio (M = Zr, V; M∶Sb = 13∶10 or 11∶8), the phases crystallize in two related structure types, namely Zr _7.5 V _5.5 Sb ₁₀ and Cr ₁₁ Ge ₈ . The lattice dimensions of Zr _7.46(5) V _3.54 Sb ₈ are a = 1514.7(1), b = 570.77(5), c = 1811.1(2) pm, V = 1565.8(2) × 10 ⁶  pm ³ (Pnma, Z = 4). The structures may be considered as intergrowths of (distorted) fragments of the W ₅ Si ₃ and NiAs structure types. In addition to M–Sb and homonuclear (and heteronuclear) M–M bonds, Sb–Sb bonding interactions, with Sb–Sb distances shorter than in elemental antimony, occur in the linear Sb chains of the W ₅ Si ₃ -analogous structural motifs. The entropy-stabilized phases decompose by annealing at lower temperatures. The metallic character was confirmed via extended Hückel calculations as well as measurements of the electrical resistivities.