3-(1H-Imidazol-1-yl)propanaminium 2-carb­oxy-4,6-di­nitro­phenolate

In the title salt, C(6)H(12)N(3) (+)·C(7)H(3)N(2)O(7) (−), the imidazole ring is planar, with a maximum deviation of 0.0013 (14) Å for the N attached to the propanaminium group. In the anion, a single intra­molecular O—H⋯O hydrogen bond is observed. The mean planes of the nitro groups in the anion are twisted from the benzene ring mean plane making dihedral angles of 24.7 (9) and 3.9 (6)°. In the crystal, the ammonium H atoms form N—H⋯N and N—H⋯O hydrogen bonds, resulting in an infinite chain along [111]. In addition to the classical hydrogen bonds, weak C—H⋯O and π–π [centroid–centroid distance = 3.7124 (9) Å] inter­actions are also observed, which lead to the formation a three-dimensional supramolecular structure that links the chains into layers along the bc plane.