Trideca­aqua­dinitratohexasodium(I) bis­[(trans-cyclo­hexane-1,2-diyldi­nitrilo­tetraacetato)­nickelate(II)]

In the title compound, [Na₆(NO₃)₂(H₂O)₁₃][Ni(C₁₄H₁₈N₂O₈)]₂, the edta-like tetraanionic unit uses two N and four O atoms to chelate to the Ni atom so that the [Ni(C₁₄H₁₈N₂O₈)]^2- portion of the structure has the Ni atom in a cis-N₂O₄Ni octahedral geometry. The [Na₆(NO₃)₂H₂O)₁₃]⁴⁺ portion exists as a chain consisting of edge-sharing NaO₆ octahedra; there are four independent Na atoms in the asymmetric unit. The vertices are derived from the O atoms of water mol­ecules, the O atom of the nitrate group as well as the O atoms of the [Ni(C₁₄H₁₈N₂O₈)]^2- unit. The layer structure is consolidated by hydrogen bonds into a three-dimensional network. Two of the Na atoms and three of the water O atoms lie on special positions of site symmetry 2.