title: catena-Poly[[[diaqua-diformatonickel(II)]-μ-1,4-bis-(1H-benzimidazol-1-yl)benzene] dihydrate].
abstract: 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) octa-hedral coordination geometry. The bzb mol-ecule acts as a bridging ligand to connect the metal atoms into a chain propagating in [1[Formula: see text][Formula: 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.
authors.affiliation: Department of Applied Chemistry, Yuncheng University, Yuncheng, Shanxi 044000,  People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Sun
authors.forename: Xiaochuan
authors.initials: X
authors.lastname: Chai
authors.forename: Chenzhong
authors.initials: C
authors.lastname: Yao