Chain and ring motifs in bis(creatininium) sulfate

The title compound, 2C4H8N3O+·SO42−, crystallizes with two creatininium cations and one sulfate anion in the asymmetric unit. Cations and anions dimerize through N—H⋯O hydrogen bonds forming R22(8) ring motifs. Furthermore, these rings are connected via N—H⋯O hydrogen bonds, leading to C22(6) and C22(8) chain motifs. These inter­actions lead to a parallel set of hydrogen-bonded lamellar aggregations propagating along the c axis of the unit cell. Another cation is situated above these sheets, leading to a grid-like structure.