The title compound, (CH6N3)[Zn2(C7H3NO5)2(C7H4NO5)- (H2O)]2H2O, has an anionic binuclear complex of ZnII balanced with a guanidinium cation. There are two uncoordinated water molecules in the structure. The asymmetric unit of the compound has two different coordination types (the coordination of Zn1 is distorted trigonal-bipyramidal, while that of Zn2 is distorted octahedral) of ZnII in the crystal structure that are bridged to each other via one hypydc2 group (hypydcH2 is 4-hydroxypyridine-2,6-dicarboxylic acid). A variety of intermolecular O—H O, N—H O and C— H O hydrogen bonds involving water molecules, cations and anions, and also a weak – interaction [3.798 (1) A ° ], are responsible for extending the structure into a three-dimensional network.
