Phenyl­hydrazinium (6-carb­oxy­pyridine-2-carboxyl­ato)(pyridine-2,6-dicarboxyl­ato)cobaltate(II)–pyridine-2,6-dicarb­oxy­lic acid–water (1/1/3)

The asymmetric unit of the title compound, (C(6)H(9)N(2))[Co(C(7)H(3)NO(4))(C(7)H(4)NO(4))]·C(7)H(5)NO(4)·3H(2)O, contains one (6-carb­oxy­pyridine-2-carboxyl­ato)(pyridine-2,6-dicarboxyl­ato)cobaltate(II) anion, one phenyl­hydrazinium cation, one pyridine-2,6-dicarb­oxy­lic acid mol­ecule and three uncoordin­ated water mol­ecules, part of which are disordered. The Co(II) ion is coordinated by a pyridine-2,6-dicarboxyl­ate ion and a 6-carb­oxy­pyridine-2-carboxyl­ate ligand almost perpendicular to each other [the angle between the least-squares planes is 87.38 (4)°] and is surrounded by two O atoms and two N atoms in the equatorial plane and two O atoms in axial positions, resulting in a distorted octa­hedral coordination geometry. There is an extensive three-dimensional network of O—H⋯O and N—H⋯O hydrogen bonds, which link the components.