Crystal structure of dicyclohexylammonium nitrate(V)

In the title molecular salt, C12H24N+·NO3 −, the cyclohexyl rings adopt chair conformations with the exocyclic C—N bonds in equatorial orientations. In the crystal, a bifurcated N—H⋯(O,O) hydrogen bond links the cation to the anion; the ion pairs are linked via C—H⋯O hydrogen bonds, forming layers in the ac plane.

In the crystal, the N1-H2N···O2 i hydrogen bonds combine ion pairs into infinite chains parallel to the c axis. The chains are additionally stabilized by C12-H12···O3 iii contacts and further packed in a parallel fashion by means of C62 -H62A···O1 ii and C11-H11···O1 ii (symmetry codes as in Table 1) interactions giving rise to layers in the ac plane ( Fig.   2).

S2. Synthesis and crystallization
Dicyclohexylamine (1 mmol, 201 ml) was added to methanol (4 ml) under vigorous stirring. The clear solution was combined with nitric(V) acid (1 M, 1 ml) and stirred for 20 min. The resulting solution was left to crystallize at room temperature. After one week, large block-shaped colourless single crystals of the title salt suitable for X-ray diffraction analysis were obtained.

S3. Refinement
The N-bound H atoms were located in a difference Fourier map and freely refined. The C-bound H atoms were positioned geometrically and refined using a riding model; C-H = 0.99 Å with U iso (H) = 1.2U eq (C).

Figure 1
The asymmetric unit of the title molecular salt, showing the atom-numbering scheme and the symmetry-independent hydrogen bonds (orange and light-blue dashed lines; see Table 1). Displacement ellipsoids are drawn at the 50% probability level.

Figure 2
A view along the b axis of the crystal packing of the title molecular salt, showing the hydrogen-bonded chains assembled into a layer in the ac plane. Hydrogen bonds are drawn as yellow and light-blue dashed lines (see Table 1). H atoms on C atoms of the cyclohexane rings not involved in hydrogen bonds have been omitted for clarity. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.21 e Å −3 Δρ min = −0.19 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 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.