STRUCTURE OF THE LAYER COMPOUND ZRSITE

Zirconium silicon telluride, ZrSiTe, crystallizes in a layer-type stru cture which is- related to the PbFCl type. The Zr atom is coordinated by four Si and four Te atoms. The Si and Te atoms are arranged in squa re planes. These planes are situated at opposite sides of the Zr atom; the coordination polyhedron may be described as a distorted quadratic antiprism. The distances between the Si atoms [2.614 (1) angstrom] ar e longer than that of a Si-Si single bond (2.35 angstrom), but compara ble with the Si-Si separations in transition-metal disilicides. The Te -Te separations within the Te, plane give no indication of significant interactions. The distances between Zr and Te atoms of neighbouring l ayers [3.957 (1) angstrom] are too long for Zr-Te bonds. Hence, contra ry to the isotypic compounds ZrSiX (X = S, Se) and ZrGeX (X = S, Se, T e), ZrSiTe is best described as a layer compound.