catena-Poly[[[aqua(2,2′-bipyridine-N,N′)nickel(II)]-μ-3,5-dinitrosalicylato-κ3O,O′:O"] 0.2-hydrate]

In the title complex, {[Ni(C7H2N2O7)(C10H8N2)(H2O)] center dot 0.2H(2)O}(n), the Ni-II atom is coordinated by three O atoms from two symmetry-related 3,5-dinitrosalicylate ligands, two N atoms from one 2,2'-bipyridine and one water molecule, and its environment displays a distorted octahedral geometry. The short face-to-face distances between parallel 2,2'-bipyridine planes of neighbouring complexes and neighbouring one-dimensional chains indicate pi-pi stacking. The packing is further influenced by inter- and intramolecular hydrogen-bond interactions.