Tris(N,N-dimethylanilinium) tri-μ-bromido-bis[tribromidoantimonate(III)]

In the title compound, (C8H12N)3[Sb2Br9], two of the three unique N,N-dimethyanilinium cations exhibit flip–flop disorder with an occupancy ratio of 0.58 (1):0.42 (1). N—H⋯Br hydrogen bonds link the organic cations and bioctahedral face-sharing anions into a three-dimensional network.

In the title compound, (C 8

Experimental
Crystals of (C 8 H 12 N) 3 [Sb 2 Br 9 ] were obtained by dissolving antimony (III) oxide Sb 2 O 3 and N,N-dimethylanilinium bromide C 8 H 12 NBr (molar ratio 3:1) in 50 ml of a solution of HBr (24%). After a slow solvent evaporation prismatic yellow crystals suitable for X-ray analysis were obtained. They were washed with diethyl ether and dried over P 2 O 5 .

Refinement
The positions of the two disordered N,N-dimethylanilinium cations were initially refined with different occupancy ratios, but the refinement converged extremely slowly when using anisotropic atomic displacement parameters. Since the refined occupancy factors for the two cations were nearly equal upon refining with isotropic atomic displacement parameters it was decided to use a single occupancy factor for the final anisotropic refinement. SADI and EADP supplementary materials sup-2 Acta Cryst. (2013). E69, m353 restraints were used. All H atoms were geometrically positioned and treated as riding on their parent atoms, with C-H = 0.93 Å for the phenyl, 0.96 Å for the methyl and N-H = 0.91 Å with U iso (H) = 1.2 U eq (C-phenyl, N) or 1.5 U eq (Cmethyl).

Figure 1
The asymmetric part of the unit cell of (C 8 H 12 N) 3 Sb 2 Br 9 crystal at 296 (2) K with the atom labeling scheme.  The crystal packing of (C 8 H 12 N) 3 Sb 2 Br 9 showing the hydrogen bonding network as blue dashed lines.

Tris(N,N-dimethylanilinium) tri-µ-bromido-bis[tribromidoantimonate(III)]
Crystal data (C 8   Special details Experimental. Absorption correction: empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. CrysAlis RED (Oxford Diffraction 2009) Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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.