2,6-Di­amino-4-chloro­pyrimidinium 4-carb­oxy­butano­ate

In the title mol­ecular salt, C(4)H(6)ClN(4) (+)·C(5)H(7)O(4) (−), the cation is essentially planar, with a maximum deviation of 0.037 (1) Å for all non-H atoms. The anions are self-assembled through O—H⋯O hydrogen bonds, forming a supra­molecular zigzag chain with graph-set notation C(8). In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxyl­ate O atoms of the anion via a pair of N—H⋯O hydrogen bonds with an R (2) (2)(8) ring motif. This motif further self-organizes through N—H⋯O and O—H⋯O hydrogen bonds, generating an array of six hydrogen bonds, the rings having graph-set notation R (3) (2)(8), R (2) (2)(8), R (4) (2)(8), R (2) (2)(8) and R (3) (2)(8). In addition, another type of R (2) (2)(8) motif is formed by inversion-related pyrimidinium cations via N—H⋯N hydrogen bonds, forming a two-dimensional network parallel to (101).