title: Poly[[tetra-aqua-bis[μ(3)-1-ethyl-6-fluoro-4-oxo-7-(piperazinium-1-yl)-1H-quinoline-3-carboxyl-ato]dinickel(II)] hydroxide nitrate].
abstract: In the title compound, [Ni(2)(C(16)H(18)FN(3)O(3))(2)(H(2)O)(4)](OH)(NO(3)), the cationic [Ni(2)(C(16)H(18)FN(3)O(3))(2)(H(2)O)(4)](2+) building units are linked through Ni-O(carboxyl-ate) and Ni-N(amino) bridges into a layer structure. The two independent nickel atoms lie on inversion centres: one adopts an NiO(6) octa-hedral geometry, the other a trans-NiN(2)O(4) octahedral arrangement. The charge-balancing hydroxide and nitrate ions are of half site occupancy each. A network of O-H⋯O and N-H⋯O hydrogen bonds helps to establish the packing.
authors.forename: Wen-Dong
authors.initials: WD
authors.lastname: Song
authors.forename: Yi-Ling
authors.initials: YL
authors.lastname: Wan
authors.forename: Peng-Zhi
authors.initials: PZ
authors.lastname: Hong
authors.forename: Seik Weng
authors.initials: SW
authors.lastname: Ng