2,3,4-Tribromothiophene

In the title compound, C4HBr3S, there are two essentially planar molecules in the asymmetric unit. In the crystal structure, bifurcated C—H⋯Br hydrogen bonds link the molecules into chains. Weak Br⋯Br interactions [Br⋯Br = 3.634 (4)–3.691 (4) Å] then lead to undulating sheets in the bc plane.

In the title compound, C 4 HBr 3 S, there are two essentially planar molecules in the asymmetric unit. In the crystal structure, bifurcated C-HÁ Á ÁBr hydrogen bonds link the molecules into chains. Weak BrÁ Á ÁBr interactions [BrÁ Á ÁBr = 3.634 (4)-3.691 (4) Å ] then lead to undulating sheets in the bc plane.

Structure Reports Online
The asymmetric unit of the title compound, (I), C 8 H 2 Br 6 S 2 , consists of two discrete tribromothiophene molecules A & B ( Fig. 1). Each molecule is essentially planar with r.m.s. deviations from the mean planes through all non-hydrogen atoms of 0.0194 and 0.0286 Å for A and B respectively. The dihedral angle between the A and B ring planes is 0.9 (4)° but they are well separated with a centroid to centroid distance of 6.3 Å.

Refinement
The crystals were small and very weakly diffracting and little data were obtainable beyond θ = 23°. This clearly contributes to the relatively high R factor and poor precision of the data in this determination. The C-bound H atoms were placed geometrically (C-H = 0.95 Å) and refined as riding with U iso (H) = 1.2U eq (C). A number of high peaks were found in the final difference map in the vicinity of the Br atoms in both molecules. The deepest hole is 0.98Å from Br3B. Fig. 1. The asymmetric unit of (I), with 50% displacement ellipsoids for the non-hydrogen atoms.

Special details
Experimental. As the crystals were small and very weakly diffracting, data were collected using 55 sec exposures per frame.
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 > 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.