title: catena-Poly[[[[3-(2-pyrid-yl)-1H-pyra-zole]nickel(II)]-μ-oxalato] sesquihydrate].
abstract: In the title compound, {[Ni(C(2)O(4))(C(8)H(7)N(3))]·1.5H(2)O}(n), both unique Ni(II) ions are chelated by an O,O'-bidentate oxalate ion and an N,N'-bidentate 3-(2-pyrid-yl)pyrazole mol-ecule. A second, symmetry-generated, oxalate ion completes a distorted cis-NiN(2)O(4) octa-hedral geometry for both metal centres. The bridging oxalate ions result in two distinct wave-like polymeric chains propagating in [100]. The packing is consolidated by N-H⋯O and O-H⋯O hydrogen bonds. The crystal studied was found to be an inversion twin.
authors.forename: Bin
authors.initials: B
authors.lastname: Jiang
authors.forename: Zhilu
authors.initials: Z
authors.lastname: Liu