Date Published: May 01, 2010
Publisher: International Union of Crystallography
Author(s): Vladimir V. Bon, Anatolij V. Dudko, Alexandra N. Kozachkova, Vasily I. Pekhnyo, Natalia V. Tsaryk.
The title compound, [Ni(C2H8NO6P2)2(H2O)2]·9H2O, exhibits a slightly distorted octahedral coordination environment around the NiII atom. It contains two molecules of 1-aminoethylidenediphosphonic acid in the zwitterionic form, coordinated via O atoms from two phosphonate groups and creating two six-membered chelate rings. Two water molecules in cis positions complete the coordination environment of the NiII atom. The title compound contains nine partly disordered solvent water molecules, which create a three-dimensional network of strong O—H⋯O and N—H⋯O hydrogen bonds.
For general background to the use of organic diphosphonic acids, see: Matczak-Jon & Videnova-Adrabinska (2005 ▶). For applications of transition-metal bisphosphonates, see: Eberhardt et al. (2005 ▶). For related structures, see: Li et al. (2007 ▶); Dudko et al. (2009 ▶).