Experimental

R factor = 0.054; wR factor = 0.179; data-to-parameter ratio = 15.0. In the title compound, C5H7N2 +C6H2N3O7, there are two crystallographically independent cations and anions (A and B) in the asymmetric unit. In both picrate anions, one of the nitro groups lies in the plane of the benzene ring [r.m.s. deviations = 0.014 (2) and 0.014 (2) A ̊ for anionsA and B, respectively] and the other two are twisted away by 39.0 (2) and 18.8 (2) in A, and 18.2 (1) and 2.5 (2) in B. In the crystal, the cations and anions are linked by intermolecular N—H O and C—H O hydrogen bonds, forming a two-dimensional network. Related literature For general background to picrate complexes, see: In et al. (1997); Zaderenko et al. (1997)