5-Carboxy-2-isopropyl-1H-imidazol-3-ium-4-carboxylate monohydrate

In the title compound, C8H10N2O4·H2O, the imidazole N atom is protonated and one of the carboxylate groups is deprotoned, forming a zwitterion. An intramolecular O—H...O hydrogen bond occurs. The crystal structure is stabilized by intermolecular N—H...O and O—H...O hydrogen bonds. In addition, intermolecular N—H...O and O—H...O hydrogen bonds link the molecules into two-dimensional networks parallel to (10overline{2}).