Crystal structures of the three closely related compounds: bis­[(1H-tetra­zol-5-yl)meth­yl]nitramide, tri­amino­guanidinium 5-({[(1H-tetra­zol-5-yl)meth­yl](nitro)­amino}­meth­yl)tetra­zol-1-ide, and di­ammonium bis­[(tetra­zol-1-id-5-yl)meth­yl]nitramide monohydrate

In the mol-ecule of neutral bis-[(1H-tetra-zol-5-yl)meth-yl]nitramide, (I), C4H6N10O2, there are two intra-molecular N-H⋯O hydrogen bonds. In the crystal, N-H⋯N hydrogen bonds link mol-ecules, forming a two-dimensional network parallel to (-201) and weak C-H⋯O, C-H⋯N hydrogen bonds, and inter-molecular π-π stacking completes the three-dimensional network. The anion in the molecular salt, tri-amino-guanidinium 5-({[(1H-tetra-zol-5-yl)meth-yl](nitro)-amino}-meth-yl)tetra-zol-1-ide, (II), CH9N6+·C4H5N10O2-, displays intra-molecular π-π stacking and in the crystal, N-H⋯N and N-H⋯O hydrogen bonds link the components of the structure, forming a three-dimensional network. In the crystal of di-ammonium bis-[(tetra-zol-1-id-5-yl)meth-yl]nitramide monohydrate, (III), 2NH4+·C4H4N10O22-·H2O, O-H⋯N, N-H⋯N, and N-H⋯O hydrogen bonds link the components of the structure into a three-dimensional network. In addition, there is inter-molecular π-π stacking. In all three structures, the central N atom of the nitramide is mainly sp2-hybridized. Bond lengths indicate delocalization of charges on the tetra-zole rings for all three compounds. Compound (II) was found to be a non-merohedral twin and was solved and refined in the major component.