Refinement of the crystal structure of zirconyl chloride octahydrate

Abstract

The crystal structure of zirconyl chloride octahydrate, ZrOCl2•8H2O, has been refined by the least-squares method with new three-dimensional data. Existence of the [Zr4(OH)8(H2O)16]8+ tetranuclear complex has been confirmed. However, the coordination polyhedron about each zirconium atom differs considerably from the D4d antiprismatic geometry reported previously. It is, in fact, more closely related to the D2d dodecahedron, and has twofold axial symmetry within the limits of experimental error. Mean bond lengths in the [Zr4(OH)8(H2O)16]8+ complex, which approximates closely to D2d point-group symmetry, are: Zr—OH (bridging) = 2.142 ± 0.019 Å and Zr—OH2 (terminal) = 2.272 ± 0.032 Å.