Crystal structure of 4-amino-5-fluoro-2-oxo-2,3-di­hydro­pyrimidin-1-ium 3-hy­droxy­pyridine-2-carboxyl­ate

The asymmetric unit of the title salt, C(4)H(5)FN(3)O(+)·C(6)H(4)NO(3) (−), contains one 4-amino-5-fluoro-2-oxo-2,3-di­hydro­pyrimidin-1-ium (5-fluoro­cytosinium, 5FC) cation and a 3-hy­droxy­picolinate (3HAP) anion. The 4-amino-5-fluoro-2-oxo-2,3-di­hydro­pyrimidine mol­ecule is protonated at one of the pyrimidine N atoms. The typical intra­molecular N—H⋯F and O—H⋯O S(5) and S(6) hydrogen-bond ring motifs are observed in the cations and anions. The protonated N atom and 2-amine group of the 5FC cation inter­act with the 3HPA anion through a pair of nearly parallel N—H⋯O hydrogen bonds, forming a robust R (2) (2)(8) ring motif. The ions are further linked by N—H⋯N, O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, generating R (2) (2)(7), R (3) (3)(12) and R (6) (5)(18) ring motifs, respectively, leading to supra­molecular wave-like sheets parallel to (010). The crystal structure is further stabilized by C—H⋯π inter­actions, generating a three-dimensional architecture.