1-Isopropylideneamino-1H-tetrazol-5-amine

The molecule of the title compound, C4H8N6, assumes an approximately planar structure, the methyl C atoms and the C atom to which they are bonded being out of the mean tetrazole ring plane by 0.108 and 0.139, and 0.144 Å, respectively. π–π stacking between parallel tetrazole rings [centroid–centroid distance = 3.4663 (11) Å] is observed in the crystal structure. Intermolecular N—H⋯N hydrogen bonding further helps to stabilize the crystal structure.

The molecule of the title compound, C 4 H 8 N 6 , assumes an approximately planar structure, the methyl C atoms and the C atom to which they are bonded being out of the mean tetrazole ring plane by 0.108 and 0.139, and 0.144 Å , respectively.stacking between parallel tetrazole rings [centroid-centroid distance = 3.4663 (11) Å ] is observed in the crystal structure. Intermolecular N-HÁ Á ÁN hydrogen bonding further helps to stabilize the crystal structure.

Experimental
Data collection: CrystalClear (Rigaku, 2008); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999). Comment 1,5-diaminotetrazole and its derivatives have received an increasing interest as a class of nitrogen-rich energetic materials during the last years.These compounds exhibit prospective application in generation of gases, propellants and other combustible and thermally decomposing systems (Galvez-Ruiz et al., 2005;Joo,et al. 2008). The title compound had been prepared by Gaponnik & Karavai, but its crystal structure hadn't been reported, therefore, the structure of the title compound has been determined in our present work.

Structure Reports Online
The crystal structure of the title compound is presented in Fig. 1, The bond distances and bond angles in the title compound are similar to the corresponding distances and angles reported by Lyakhov et al. (2005). The molecule is almost planar with only C2, C3 and C4 being out of the mean plane of the tetrazole ring by 0.108, 0.144 and 0.139 Å, respectively.
In the crystal structure the molecules are linked to each other via N-H···N hydrogen bonding (Table 1), forming a three dimensional network structure). The offset face-to-face π-π contact between the tetrazole rings, related by an inversion center, further helps to stabilize the crystal structure; centroid-centroid distance being 3.4663 (11) Å.

Experimental
The title compound was prepared according to the literature method (Gaponnik & Karavai, 1984). The purity of the compound was checked by determining its melting point, m.p. 445-446 K. Crystals suitable for X-ray structure determination were obtained by slow evaporation of an acetone solution at room temperature.

Refinement
Amino H atoms were located in a difference Fourier maps and were refined isotropically. Other H-atoms were placed in calculated positions with C-H = 0.98 Å, and refined in riding mode with U iso = 1.2U eq (C). Fig. 1. The molecular structure of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.  Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Figures
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )