Carbamo­yl(di­amino­methyl­idene)aza­nium 3-nitro-5-oxo-4,5-di­hydro-1H-1,2,4-triazol-4-ide

In the anion of the title salt, C2H7N4O(+)·C2HN4O3 (-), the negative charge resides formally on the N(3) atom of the triazole ring. In the crystal, the N(3) and exocyclic O atoms are hydrogen-bond acceptors with respect to the formally double-bond iminium and amido N atoms of the cation. The cation and anion are almost planar (r.m.s. deviations = 0.012 and 0.051 Å, respectively), but they are slightly bent with respect to each other [dihedral angle = 12.6 (1)°]. In the crystal, adjacent anions and cations are linked by extensive N-H⋯N and N-H⋯O hydrogen bonds, generating a ribbon running along the b-axis direction.