Poly[diaquatris(μ6-4,6-dioxo-1,4,5,6-tetrahydro-1,3,5-triazine-2-carboxylato)tripotassium]

The asymmetric unit of the title compound, [K3(C4H2N3O4)3(H2O)2]n, contains two potassium cations (one in general position, one located on a twofold rotation axis), one and a half oxonate anions (the other half generated by twofold symmetry) and one water molecule. As a result of the twofold symmetry, one H atom of the symmetric anion is statistically occupied. Both potassium cations are surrounded by eight oxygen atoms in the form of distorted polyhedra. Adjacent cations are interconnected by oxygen bridges, generating layers parallel to (100). The aromatic ring system of the oxonate anions link these layers into a network structure. The crystal packing is stabilized by N—H...O, O—H...O and O—H...N hydrogen bonds, three of which are bifurcated. In addition, intermolecular π–π stacking interactions exist between neighboring aromatic rings with a centroid–centroid distance of 3.241 (2) Å.