Bis(oxonium) tetrakis(o-toluidinium) cyclohexaphosphate

In the title compound, 4C7H10N+·2H3O+·P6O18 6−, the complete cyclohexaphosphate anion is generated by crystallographic inversion symmetry. In the crystal, the H3O+ ions and the [P6O18]6− anions are linked by O—H⋯O hydrogen bonds, generating infinite layers lying parallel to the ab plane at z = 1/2. These layers are interconnected by the organic cations, which establish N—H⋯O hydrogen bonds with the [P6O18]6− anions.

In the title compound, 4C 7 H 10 N + Á2H 3 O + ÁP 6 O 18 6À , the complete cyclohexaphosphate anion is generated by crystallographic inversion symmetry. In the crystal, the H 3 O + ions and the [P 6 O 18 ] 6À anions are linked by O-HÁ Á ÁO hydrogen bonds, generating infinite layers lying parallel to the ab plane at z = 1 2 . These layers are interconnected by the organic cations, which establish N-HÁ Á ÁO hydrogen bonds with the [P 6 O 18 ] 6À anions.
Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1996); program(s) used to solve structure: SHELXS86 (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 Many cyclohexaphosphates of organic cations and inorganic cations (mono, bi and trivalent) have been synthesized and structurally characterized. But the association of the oxonium cation to this kind of material is very rare. On the other hand, there is only one cyclohexaphosphate of mixed cation (organic-oxonium) (Amri, et al., 2008). In this work, we report the preparation and the structural investigation of a new organic oxonium cyclohexaphospohate, (o-CH 3 C 6 H 4 NH 3 ) 4 (H 3 O) 2 P 6 O 18 , The title compound is built up from P 6 O 18 6anion, four organic o-toluidinium and two oxonium cations (Fig. 1). The half of the anion, two organic and one oxonium cations constitute the asymmetric unit of (I It is worth noting that the H 3 O + ions exhibit a pyramidal geometry. These layers formed by P 6 O 18 groups and oxonium ions cross the unit cell parallel to the (a, b) plane at z = 1/2 (  In order to avoid the hydrolysis of the ring anion the above reaction is performed at room temperature. The so-obtained solution is then slowly evaporated until1 the formation of pink prisms of (I). The title compound is stable for months under normal conditions of temperature and relative humidity.
Figures Fig. 1. The molecular structure of (I) with displacement ellipsoids drawn at the 30% probability level. H atoms are represented as small spheres of arbitrary radii. Symmetry code: i: -x, -y, -z.

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 )
x y z U iso */U eq P1 0.19977 (