Poly[[diaqua­nickel(II)]-μ2-4,4′-bipyridine-κ2 N:N′-μ-p-phenyl­enedioxy­diacetato-κ2 O:O′]

The title coordination polymer, [Ni(C(10)H(8)O(6))(C(10)H(8)N(2))(H(2)O)(2)](n), was obtained by the hydro-thermal reaction of nickel(II) sulfate, benzene-1,4-dioxy-diacetic acid (p-phenyl-enedioxy-diacetic acid) and 4,4'-bipyridine (4,4'-bpy) in alkaline aqueous solution. Each Ni(II) atom is coordinated by two O atoms from two benzene-1,4-dioxy-diacetate ligands, two N atoms from two 4,4'-bpy ligands and two water mol-ecules, and displays a distorted octa-hedral geometry. The Ni(II) atom and benzene-1,4-dioxy-diacetate and 4,4'-bpy moieties lie on inversion centres. The benzene-1,4-dioxy-diacetate ligands bridge the Ni(II) atoms to form infinite zigzag chains, which are further inter-connected by 4,4'-bpy ligands to form a grid-like layer parallel to the (01) plane. Moreover, there are O-H⋯O hydrogen-bonding inter-actions within the grid-like layer between the coordinated water mol-ecules and the carboxyl-ate O atoms.