1,5-Diaminotetrazolium chloride

The title compound, CH5N6 +·Cl−, crystallized with two indepedent 1,5-diaminotetrazolium cations and two independent chloride anions in the asymmetric unit. In the crystal, there are a number of N—H⋯Cl hydrogen-bonding interactions, which generate a three-dimensional network.

The title compound, CH 5 N 6 + ÁCl À , crystallized with two indepedent 1,5-diaminotetrazolium cations and two independent chloride anions in the asymmetric unit. In the crystal, there are a number of N-HÁ Á ÁCl hydrogen-bonding interactions, which generate a three-dimensional network.

Comment
The synthesis and study of nitrogen-rich energetic salts and highly energetic materials for possible military as well as civil applications has attracted considerable interest in recent years, especially the salts with tetrazole-containing compounds (Galvez-Ruiz et al., 2005;Denffer et al., 2008). The nitrogen content of 5-amniotetrazole and 1,5-diaminotetrazole, which are primary sources for preparing energetic salts, is 82.3% and 84%, respectively. Denffer et al. (2008) reported the synthesis of 5-aminotetrazolium hydrochloride and determinated its crystal structure. Our rearch group has recently reported on the synthesis of the title compound (He et al.., 2009a,b), and herein we report on its crystal structure.
The molecular structure of the title molecule is presented in Fig. 1. It crystallizes with two independent 1,5-Diaminotetrazolium cations and two independent chloride anions per asymmetric unit. The bond distances and angles are as expected for a molecule of this kind, and are similar to the corresponding distances and angles reported by (He et al., 2009a,b). The cations, excluding the N6 and N11 hydrogen atoms, are planar (maximum deviation 0.020 (2) Å).
In the crystal there are a number of N-H···Cl hydrogen bonds which result in the foamation of a three-dimensional network (Table 1).
1,5-diaminotetrazole (2.0043 g, 20.04 mmol) suspended in 40 mL of methanol, was reacted with 10 mL concentrated HCl. The reaction mixture was refluxed for 2 h and then the solvent was evaporated until precipitation occured. The concentrated solution was then placed in the refrigerator, and the white 1,5-diaminotetrazolium hydrochloride was obtained. The precipitate was filtered off and washed with water. The crude product was recrystallized from methanol (Yield: 2.4189 g, 88.6%).
Crystals suitable for X-ray structure determination were obtained by slow evaporation of a solution in methanol at rt.

Refinement
In the final cycles of refinement, in the absence of significant anomalous scattering effects, Friedel pairs were merged and Δf " set to zero. All the H-atoms were located in difference Fourier maps and were freely refined: N-H = 0.79 (4) -0.96 (4) Å.
supplementary materials sup-2 Figures   Fig. 1. The molecular structure of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.