4-Methyl­anilinium 3-carb­oxy-2-hy­droxy­propano­ate

The title mol­ecular salt, C7H10N+·C4H5O5−, contains a 4-methyl­anilinium cation and a 3-carb­oxy-2-hy­droxy­propano­ate (hydrogen 2-hy­droxy­succinate) anion in the asymmetric unit. The cation is protonated at the amine N atom and the anion is deprotonated at one of the hy­droxy O atoms of the carb­oxy­lic acid groups. An O—H⋯O hydrogen bond in the anion generates an S(5) graph-set motif. An N—H⋯O hydrogen bond links the anion and cation in the asymmetric unit. In the crystal, N—H⋯O and O—H⋯O hydrogen bonds link adjacent anions and cations, forming a two-dimensional network parallel to the ac plane and enclosing R23(12), R23(14) and R32(10) ring motifs.