Guanidinium hexa­aqua­zinc(II) bis[tris­(3-carb­oxy­pyridine-2-carboxyl­ato)zincate]

In the title mol­ecular salt, (CH(6)N(3))(1.30)[Zn(H(2)O)(6)](0.35)[Zn(C(7)H(4)NO(4))(3)](2), the Zn(II) atom (site symmetry 3) in the anion is coordinated by three N,O-bidentate 3-carb­oxy­pyridine-2-carboxyl­ate monoanions to generate a fac-ZnN(3)O(3) octa­hedral coordination geometry. The guanidinium cation (the C atom has site symmetry 3) and the octa­hedral hexa­aqua­zinc(II) dication (the Zn(2+) cation has site symmetry -3) are occupationally disordered in a 1.30:0.35 ratio. In the crystal, the components are linked by O—H⋯O and N—H⋯O hydrogen bonds to generate infinite (001) sheets. Weak aromatic π–π stacking [centroid–centroid distance = 3.797 (8) Å] is also observed in the crystal.