catena-Poly[[[diaqua­diformatonickel(II)]-μ-1,4-bis­(1H-benzimidazol-1-yl)benzene] dihydrate]

In the title one-dimensional coordination polymer, {[Ni(CHO(2))(2)(C(20)H(14)N(4))(H(2)O)(2)]·2H(2)O}(n), the Ni(II) atom lies on a crystallographic inversion centre. It is coordinated by two formate O atoms, two water O atoms and two N atoms from two 1,4-bis­(1H-benzimidazol-1-yl)benzene (bzb) ligands, resulting in a distorted trans-NiN(2)O(4) octa­hedral coordination geometry. The bzb mol­ecule acts as a bridging ligand to connect the metal atoms into a chain propagating in [1[Image: see text] [Image: see text]]. The dihedral angle between the benzimidazole ring and the central benzene ring in the ligand is 38.16 (9)°. In the crystal, O—H⋯O hydrogen bonds crosslink the chains into (010) sheets.