Poly[[diaqua­nickel(II)]-μ(2)-4,4′-bipyridine-κ(2) N:N′-μ-p-phenyl­enedioxy­diacetato-κ(2) 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 hydro­thermal reaction of nickel(II) sulfate, benzene-1,4-dioxy­diacetic acid (p-phenyl­enedioxy­diacetic 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-dioxy­diacetate ligands, two N atoms from two 4,4′-bpy ligands and two water mol­ecules, and displays a distorted octa­hedral geometry. The Ni(II) atom and benzene-1,4-dioxy­diacetate and 4,4′-bpy moieties lie on inversion centres. The benzene-1,4-dioxy­diacetate ligands bridge the Ni(II) atoms to form infinite zigzag chains, which are further inter­connected by 4,4′-bpy ligands to form a grid-like layer parallel to the (0[Image: see text]1) plane. Moreover, there are O—H⋯O hydrogen-bonding inter­actions within the grid-like layer between the coordinated water mol­ecules and the carboxyl­ate O atoms.