The Crystal Structure of Hexaamminecobalt(III) Tetrachlorozincate(II) Chloride, [Co(NH3)(6)] [ZnCl4]Cl

The crystal structure of hexaamminecobalt(III) tetrachlorozincate(II) chloride, [Co(NH3)(6)] [ZnCl4]Cl, has been determined from three-dimensional X-ray data collected by counter methods. The structure has been refined by full-matrix least-squares techniques to a final R factor, on F, of 3.4% for the 1329 independent reflections that are above background. The material crystallizes in the orthorhombic space group D-2h,-Pnma, with four formula units in a cell of dimensions a = 21.219 (9), b = 7.653 (4), and c = 8.106 (3) angstrom. The calculated and observed densities are 2.037 and 2.02 0.01 g/cm(3), respectively. Both the cation and the ZnCl6(2-) anion are required crystallographically to possess m symmetry. The Co(NH3)(6)(3+) ion is a slightly distorted octahedron, whereas the structure of the tetrachlorozincate(II) is distorted appreciably from a tetrahedron. The four independent Co-N bond lengths are 1.988 (5), 1.977 (3), 1.953 (3), and 1.974 (5) angstrom, and the independent Zn-Cl distances are 2.358 (2), 2.269 (1), and 2.223 (2) angstrom.