Oxonium 5-aminouracil-6-sulfonate hydrate

In the title compound, oxonium 5-amino-2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-sulfonate hydrate, H3O(+)-C4H4N3O5S(-)-H2O, the sulfonate group is in the anionic form and charge balance is provided by an oxonium cation, H3O(+). Screw-related molecules overlap significantly and are hydrogen bonded to form a zigzag chain of the uracil skeleton along the direction of the c screw axis. The partially stacked bases and their glide-related equivalents run parallel to the a axis to form hydrophobic zones separated by hydrophilic zones built up by a network of hydrogen bonds.