Received 2 September 2009
In the title compound, [Ni(C12H6N2O4)(H2O)4]·2H2O, obtained from a basic solution of 2,2'-bipyridine-5,5'-dicarboxylate and nickel(II) chloride in water, the central Ni(II) cation (site symmetry 2) is coordinated by two N atoms from the 2,2'-bipyridine-5,5'-dicarboxylate ligand and four aqua O atoms. The N-Ni-N angle is 78.64 (8)°. Weak but significant - stacking interactions exist between the pyridine rings with a centroid-centroid distance of 3.652 (8) Å. In addition, four O atoms of the two carboxyl groups form hydrogen bonds with both coordinated and uncoordinated water molecules, forming an infinite three-dimensional network.
Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: NG2636 ).
The author thanks the financial support of Natural Foundation of Heilongjiang Province.
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