5-(4-Chlorophenyl)-1H-tetrazole

The two independent molecules of the title compound, C7H5ClN4, both lie on a twofold rotation axis that passes through the centroids of the five- and six-membered rings and the attached Cl C atom. One molecule is nearly planar [dihedral angle between rings = 0.22 (6)°], whereas the other is significantly twisted [dihedral angle = 17.38 (6)°]. In the crystal, adjacent molecules are linked by N—H⋯N hydrogen bonds into a chain structure.

The two independent molecules of the title compound, C 7 H 5 ClN 4 , both lie on a twofold rotation axis that passes through the centroids of the five-and six-membered rings and the attached Cl C atom. One molecule is nearly planar [dihedral angle between rings = 0.22 (6) ], whereas the other is significantly twisted [dihedral angle = 17.38 (6) ]. In the crystal, adjacent molecules are linked by N-HÁ Á ÁN hydrogen bonds into a chain structure.
In the asymmetric unit of the title compound, C 7 H 5 ClN 4 , contains two half molecules of 5-(4-Chlorophenyl)-1H-tetrazole. In these two molecules, the centres of bezene and tetrazole rings locate on the symmetry plane, with the dihedral angle of 0.22 (6)° and 17.38 (6)°, respectively.
A one-dimensional chain structure is built up by N-H···N hydrogen bonds between the imino groups of the title compound.
Then, it was cooled to room temperature and poured into cold water and acidified to pH = 2 with concentrated hydrochloric acid. The suspension was filtrated, and the residue was washed with water and ethanol for several times, and then dried (11.1 g, 61.8 %). Crystals suitable for X-ray analysis were obtained by recrystallization in the EtOH solution.

Refinement
Due to the title compound molecules located on the symmetry planes, the H atoms bound to N atoms were disordered into two positions with the occupancies of 0.5, respectively. H atoms bound to N atoms were located in a difference Fourier map and refined freely. H atoms bound to C atoms were placed in calculated positions and treated as riding on their parent atoms, with C-H = 0.93 Å (aromatic) and U iso (H) = 1.2U eq (C). Fig. 1

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
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.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )