Crystal structure of [Ni(OH2)6]Cl2•(18-crown-6)2•-2H2O

The crystal structure of the title compound, hexaaquanickel(II) dichloride-1,4,7,10,13,16-hexaoxacyclooctadecane-water (1/2/2), [Ni(H2O)(6)]Cl-2-center dot 2C(12)H(24)O(6)center dot 2H(2)O, is reported. The asymmetric unit contains half of the Ni(OH2)(6) moiety with a formula of C12H32ClNi0.50O10 at 105 K and triclinic (P (1) over bar) symmetry. The [Ni(OH2)(6)](2+) cation has close to ideal octahedral geometry with O-Ni-O bond angles that are within 3. of idealized values. The supramolecular structure includes hydrogen bonding between the water ligands, 18-crown-6 molecules, Cl anions, and co-crystallized water solvent. Two crown ether molecules flank the [Ni(OH2)(6)](2+) molecule at the axial positions in a sandwich-like structure. The relatively symmetric hydrogen-bonding network is enabled by small Cl counter-ions and likely influences the more idealized octahedral geometry of [Ni(OH2)(6)](2+).