3-Cyanoanilinium iodide monohydrate

In the crystal structure of the title compound, C7H7N2 +·I−·H2O, [C7H7N2 +]n chains extending along the a-axis direction are linked via N—H⋯N hydrogen bonds. The cations are further connected to the anions by N—H⋯I, N—H⋯O and O—H⋯I hydrogen bonds, leading to the formation of a sheet parallel to the ac plane. π–π interactions [centroid–centroid distance = 3.8378 (7) Å] link the sheets into a three-dimensional network.

In the crystal structure of the title compound, C 7 H 7 N 2 + ÁI À Á-H 2 O, [C 7 H 7 N 2 + ] n chains extending along the a-axis direction are linked via N-HÁ Á ÁN hydrogen bonds. The cations are further connected to the anions by N-HÁ Á ÁI, N-HÁ Á ÁO and O-HÁ Á ÁI hydrogen bonds, leading to the formation of a sheet parallel to the ac plane.interactions [centroid-centroid distance = 3.8378 (7) Å ] link the sheets into a threedimensional network.

Comment
Salts of amides attracted much attention as phase transition dielectric materials for applications in micro-electronics and memory storage (Fu et al. 2007;Fu et al. 2009). With the purpose of obtaining phase transition crystals of 3-aminobenzonitrile salts, its interaction with various acids has been studied and we have elaborated a series of new materials with this organic molecule. In this paper, we describe the crystal structure of the title compound, 3-cyanoanilinium iodine monohydrate.

Experimental
The commercial available 3-aminobenzonitrile (3 mmol, 324 mg) was dissolved in water/HI (50:1 v/v) solution. The solvent was slowly evaporated in air affording colourless block-shaped crystals of the title compound suitable for X-ray analysis.
While permittivity measurements show that there is no phase transition within the temperature range (from 100 K to 400 K), the permittivity is 6.8 at 1 MHz at room temperature.

Refinement
All H atoms attached to C atoms were fixed geometrically and treated as riding with C-H = 0.93 Å, with U iso (H) = 1.2Ueq(C).  Fig. 1. A view of the title compound with the atomic numbering scheme. Displacement ellipsoids were drawn at the 30% probability level.

Special details
Geometry. All e.s. 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 N1