2-Amino-5-chloro­pyrimidin-1-ium hydrogen maleate

In the title salt, C(4)H(5)ClN(3) (+)·C(4)H(3)O(4) (−), the 2-amino-5-chloro­pyrimidinium cation is protonated at one of its pyrimidine N atoms. In the roughly planar (r.m.s. deviation = 0.026 Å) hydrogen malate anion, an intra­molecular O—H⋯O hydrogen bond generates an S(7) ring. 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, forming an R (2) (2)(8) ring motif. The ion pairs are connected via further N—H⋯O hydrogen bonds and a short C—H⋯O inter­action, forming layers lying parallel to the bc plane.