Crystal structure of a second triclinic polymorph of 2-methyl­pyridinium picrate

The title mol­ecular salt, C(6)H(8)N(+)·C(6)H(2)N(3)O(7) (−) (systematic name: 2-methyl­pyridinium 2,4,6-tri­nitro­phenolate), crystallizes with two cations and two anions in the asymmetric unit. In the crystal, the cations are linked to the anions via bifurcated N—H⋯(O,O) hydrogen bonds, generating R (1) (2)(6) graph-set motifs. Numerous C—H⋯O hydrogen bonds are observed between these cation–anion pairs, which result in a three-dimensional network. In addition, weak aromatic π–π stacking between the 2-methyl­pyridinium rings [inter-centroid distance = 3.8334 (19) Å] and very weak stacking [inter-centroid distance = 4.0281 (16) Å] between inversion-related pairs of picrate anions is observed. The title salt is a second triclinic polymorph of the structure (also with Z′ = 2) reported earlier [Anita et al. (2006). Acta Cryst. C62, o567–o570; Chan et al. (2014 ▸). CrystEngComm, 16, 4508–4538]. In the title compound, the cations and anions display a chequerboard arrangement when viewed down [100], whereas in the first polymorph, (010) layers of alternating cations and anions are apparent in a [100] view. It is inter­esting that the unit-cell lengths are almost identical for the two polymorphs, although the inter-axial angles are quite different.