Guanidinium 3-carboxy-2,3-dihydroxypropanoate monohydrate

In the title hydrated salt, CH6N3+center dot C4H5O6-center dot H2O, the deprotonated carboxyl group is disordered over two positions with a site-occupancy ratio of 0.945 (3):0.055 (3). The bond lengths in the guanidinium cation are intermediate between normal C-N and C=N bond lengths, indicating significant delocalization in this species. In the crystal structure, anions and water molecules are linked into sheets parallel to the ab plane by intermolecular O-H center dot center dot center dot O hydrogen bonds. The linking of the anions and water molecules with the cations by intermolecular N-H center dot center dot center dot O hydrogen bonds creates a three-dimensional network.