2-Amino­pyridinium 2-meth­oxy­carbonyl-4,6-dinitro­phenolate

In the title mol­ecular salt, C(5)H(7)N(2) (+)·C(8)H(5)N(2)O(7) (−), the 2-amino­pyridinium cation is essentially planar, with a maximium deviation of 0.015 (1) Å, while the 2-meth­oxy­carbonyl-4,6-dinitro­phenolate anion is slightly twisted away from planarity, with a maximium deviation of 0.187 (1) Å. Deprotonation of the hy­droxy O atom was observed. The cation and anion are connected by four bifurcated N—H⋯(O,O) hydrogen bonds, forming a mol­ecular proton-transfer adduct. The dihedral angle between the pyridinium ring in the cation and the benzene ring in the anion is 3.65 (6)°. Every adduct connects to six neighboring adducts by N—H⋯O and C—H⋯O hydrogen bonds, yielding extended layers parallel to the bc plane. There is a weak π–π inter­action between the benzene rings of two neighboring anions; the inter­planar spacing and the centroid–centroid separation are 3.309 (1) and 3.69 (1) Å, respectively.