Crystal structure of tris-(trans-1,2-cyclo-hexa-ne-diamine-κ(2) N,N')chromium(III) tetra-chlorido-zincate chloride trihydrate from synchrotron data.

The structure of the title double salt, [Cr(rac-chxn)3][ZnCl4]Cl·3H2O (chxn is trans-1,2-cyclo-hexa-nedi-amine; C6H14N2), has been determined from synchrotron data. The Cr(III) ion is coordinated by six N atoms of three chelating chxn ligands, displaying a slightly distorted octa-hedral coordination environment. The distorted tetra-hedral [ZnCl4](2-) anion, the isolated Cl(-) anion and three lattice water mol-ecules remain outside the coordination sphere. The Cr-N(chxn) bond lengths are in a narrow range between 2.0737 (12) and 2.0928 (12) Å; the mean N-Cr-N bite angle is 82.1 (4)°. The crystal packing is stabilized by hydrogen-bonding inter-actions between the amino groups of the chxn ligands and the water mol-ecules as donor groups, and O atoms of the water mol-ecules, chloride anions and Cl atoms of the [ZnCl4](2-) anions as acceptor groups, leading to the formation of a three-dimensional network. The [ZnCl4](2-) anion is disordered over two sets of sites with an occupancy ratio of 0.94:0.06.