2-Ureido-1,3-thia-zol-3-ium dihydrogen phosphate.

The title compound, C4H6N3OS+·H2PO4−, (I), was obtained as a result of hydrolysis of [(1,3-thia­zol-2-yl­amino)­carbon­yl]­phospho­ramidic acid, (II), in water. X-ray analysis has shown that the N—P bond in (II) breaks, leading to the formation of the substituted carbamide (I). This compound exists as an inter­nal salt. The unit cell consists of a urea cation and an anion of H2PO4−. Protonation of the N atom of the heterocyclic ring was confirmed by the location of the H atom in a difference Fourier map. The mol­ecules of substituted urea are connected by O⋯O hydrogen bonds into unlimited planes. In turn, those planes are connected to each other via N—H⋯O hydrogen bonds with mol­ecules of phospho­ric acid, forming a three-dimensional polymer.