catena-Poly[[[diaqua-cobalt(II)]-μ-(3,5-dinitro-2-oxidobenzoato)-κO,O:O-[tetra-aqua-cobalt(II)]-μ-(3,5-dinitro-2-oxidobenzoato)-κO:O,O] dihydrate].

In polymeric title compound, {[Co(2)(C(7)H(2)N(2)O(7))(2)(H(2)O)(6)]·2H(2)O}(n), obtained from the reaction of 3,5-dinitro-salicylic acid with cobalt(II) acetate, both Co(II) atoms are located on inversion centres and exhibit a distorted octahedral coordination geometry. The coordin-ation sphere about one Co(II) atom comprises four O-atom donors from two bidentate chelate (O(phenolate) and O(carbox-yl)) and bridging dianionic ligands and two water mol-ecules [Co-O range = 2.0249 (11)-2.1386 (14) Å], while that about the second Co(II) atom has four water mol-ecules and two bridging carboxyl-ate O-donor atoms [Co-O range = 2.0690 (14)-2.1364 (11) Å]. The coordinated water mol-ecules as well as the water mol-ecules of solvation give O-H⋯O water-water and water-carboxyl hydrogen-bonding inter-actions in the three-dimensional framework structure.