1,2,3-Trifluorobenzene

In the title compound, C6H3F3, weak electrostatic and dispersive forces between C(δ+)—F(δ−) and H(δ+)—C(δ−) groups are at the borderline of the hydrogen-bond phenomenon and are poorly directional and further deformed in the presence of π–π stacking interactions. The molecule lies on a twofold rotation axis. In the crystal structure, one-dimensional tapes are formed via two antidromic C—H⋯F hydrogen bonds. These tapes are, in turn, connected into corrugated two-dimensional sheets by bifurcated C—H⋯F hydrogen bonds. Packing in the third dimension is furnished by π–π stacking interactions with a centroid–centroid distance of 3.6362 (14) Å.

In the title compound, C 6 H 3 F 3 , weak electrostatic and dispersive forces between C(+)-F(À) and H(+)-C(À) groups are at the borderline of the hydrogen-bond phenomenon and are poorly directional and further deformed in the presence ofstacking interactions. The molecule lies on a twofold rotation axis. In the crystal structure, one-dimensional tapes are formed via two antidromic C-HÁ Á ÁF hydrogen bonds. These tapes are, in turn, connected into corrugated two-dimensional sheets by bifurcated C-HÁ Á ÁF hydrogen bonds. Packing in the third dimension is furnished bystacking interactions with a centroid-centroid distance of 3.6362 (14) Å .
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LH2880).

Comment
Despite the high electronegativity difference between carbon and fluorine, the C-F bond acts as a poor hydrogen bond acceptor due to the hardness of the F-atom (Dunitz & Taylor, 1997;O'Hagan, 2008). The resultant weak C-H···F-C interactions (Howard et al., 1996;Reichenbacher et al., 2005) arise mainly due to electrostatic and dispersive forces between the C(δ+)-F(δ-) and the H(δ+)-C(δ-) fragments. These interactions, at the borderline of the hydrogen bond phenomenon, are also poorly directional and are deformed by other dominant interactions (Weiss, et al., 1997;D'Oria & Novoa, 2008;Müller et al., 2007). In the absence of other interactions these weak interactions can play a role in the overall crystal packing of the molecule (Bats et al. 2000;Choudhury et al. 2004;Althoff et al. 2006). In activated systems such as polyfluorobenzenes, C-H···F-C interactions may be of significance, and in connection there are some reports of the crystal structures of several polyfluorinated benzene compunds (Thalladi et al., 1998). As a continuation of this work, we report here the crystal structure 1,2,3-trifluorobenzene (1). The comparison crystal structures of 1,2-and 1,4-difluorobenzene and 1,3,5-trifluorobenzene have been reported in this earlier work.

Experimental
The crystals were prepared from commerical samples by zone melting in a quartz capillary at 235 K (1) according to the procedure outlined by (Boese & Nussbaumer, 1994).

Refinement
Treatment of hydrogen atoms: Riding model with the 1.2 fold isotropic displacement parameters of the equivalent U ij of the corresponding carbon atom. Fig. 1. Part of the crystal structure of 1 (a) 2D network of C-H···F-C interactions viewed along the c-axis (b) π-π stacking of molecules viewed along the c-axis.

Figures
sup-2 Fig. 2. The molecular structure of (1) with displacement ellipsoids drawn at the 50% probability level. The identically labelled atoms are related to each other by the symmetry operator (2x, y, -z+1/2).