2-Amino-5-methyl-pyridinium 2-carb-oxy-benzoate

In the title salt, C(6)H(9)N(2) (+)·C(8)H(5)O(4) (-), the hydrogen phthalate anion is essentially planar, with a maximum deviation of 0.011 (2) Å. In the crystal structure, the protonated N atom of the pyridine ring and the 2-amino group of the cation are hydrogen bonded to the carboxyl-ate O atoms of the anion via a pair of N-H⋯O hydrogen bonds, forming an R(2) (2)(8) ring motif. In the hydrogen phthalate anion, there is a very strong, almost symmetric, intra-molecular O-H⋯O hydrogen bond, generating an S(7) motif [O⋯O = 2.382 (3) Å]. Furthermore, these two molecular motif rings are connected by a bifurcated N-H⋯(O,O) hydrogen-bonded motif R(1) (2)(4), forming a supra-molecular ribbon along the b axis. The crystal structure is further stabilized by π-π inter-actions between the cations and anions [centroid-centroid distance = 3.6999 (10) Å].