Guanidinium chlorochromate

In the title compound, guanidinium chloridotrioxidochromate(VI), (CH6N3)[CrClO3], both the cation and anion are generated by crystallographic mirror symmetry, with one O and one N atom and the Cr, Cl and C atoms lying on the mirror plane. The bond lengths in the guanidinium cation are intermediate between normal C—N and C=N bond lengths, indicating significant delocalization in this species. In the crystal structure, intermolecular N—H⋯Cl interactions generate R 2 1(6) ring motifs. These ring motifs are further interconnected by intermolecular N—H⋯O hydrogen bonds into infinite chains along [010].

In the title compound, guanidinium chloridotrioxidochromate(VI), (CH 6 N 3 )[CrClO 3 ], both the cation and anion are generated by crystallographic mirror symmetry, with one O and one N atom and the Cr, Cl and C atoms lying on the mirror plane. The bond lengths in the guanidinium cation are intermediate between normal C-N and C N bond lengths, indicating significant delocalization in this species. In the crystal structure, intermolecular N-HÁ Á ÁCl interactions generate R 2 1 (6) ring motifs. These ring motifs are further interconnected by intermolecular N-HÁ Á ÁO hydrogen bonds into infinite chains along [010].
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009). HKF and JHG thank Universiti Sains Malaysia (USM) for the Research University Golden Goose grant (No. 1001/ PFIZIK/811012). JHG also thanks USM for the award of a USM fellowship. SG thanks the CSIR, Government of India, for a research grant and AK is grateful to the CSIR for a fellowship.
The bond lengths and angles are comparable to closely related guanidinium (Al-Dajani et al., 2009) and chlorochromate (Lorenzo Luis et al., 1996) structures.

Experimental
The new oxidizing reagent, guanidinium chlorochromate (GCC) was prepared by treatment of equivalent amounts of guanidinium hydrochloride and chromium trioxide in water at 273 K by stirring with a glass rod with instantaneous formation of yellow blocks of (I).

Refinement
All the H atoms were located from difference Fourier map and allowed to refine freely [Range of N-H = 0.805 (14) -0.818 (14) Å]. Fig. 1

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1)K.
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 > 2sigma(F 2 ) is used only for calculating R-factors(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 )