3-Carboxyquinolin-1-ium-2-carboxylate monohydrate

The title compound, C11H7NO4·H2O, contains a 3-carboxyquinolin-1-ium-2-carboxylate (qda) zwitterion and one water molecule. In the crystal, pairs of N—H...O hydrogen bonds link the molecules into inversion dimers, and these dimers are further connected by O—H...O hydrogen bonds into a three-dimensional supramolecular architecture. In addition, π–π interactions occur between pyridine and benzene rings from different qda ligands [centroid–centroid distance = 3.749 (1) ] and the dihedral angles of the –CO2H and –CO2 groups to the quinoline system are 8.47 (3) and 88.16 (6)°, respectively.