Bis[(diamino­methyl­idene)aza­nium] 5-(1-oxido-1H-1,2,3,4-tetra­zol-5-yl)-1H-1,2,3,4-tetra­zol-1-olate

The anion of the title salt, 2[C(NH₂)₃]⁺·C₂N₈O₂²⁻, lies on a center of inversion and its two five-membered rings are coplanar. The guanidinium cation forms N—H...O and N—H...N hydrogen bonds to the anion, generating an eight-membered ring. Other hydrogen bonds lead to the formation of a three-dimensional network.