organic compounds
1,3-Difluorobenzene
aInstitut für Anorganische Chemie der Universität, 45117 Essen, Germany, and bIndian Institute of Science, Bangalore 560 012, India
*Correspondence e-mail: roland.boese@uni-due.de, gautam_desiraju@yahoo.com
The weak electrostatic and dispersive forces between C(δ+)—F(δ−) and H(δ+)—C(δ−) are at the borderline of the hydrogen-bond phenomenon and are poorly directional and further deformed in the presence of other dominant interactions, e.g. C—H⋯π. The title compound, C6H4F2, Z′ = 2, forms one-dimensional tapes along two homodromic C—H⋯F hydrogen bonds. The one-dimensional tapes are connected into corrugated two-dimensional sheets by further bi- or trifrucated C—H⋯F hydrogen bonds. Packing in the third dimension is controlled by C—H⋯π interactions.
Related literature
For C—H⋯F interactions, see: Althoff et al. (2006); Bats et al. (2000); Choudhury et al. (2004); D'Oria & Novoa (2008); Dunitz & Taylor (1997); Howard et al. (1996); Müller et al. (2007); O'Hagan (2008); Reichenbacher et al. (2005); Weiss et al. (1997). For the crystal structures of polyfluorinated benzenes, see: Thalladi et al. (1998). For crystallization techniques, see: Boese & Nussbaumer (1994).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2008); cell SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: Mercury (Macrae et al., 2008) and GIMP (The GIMP team, 2008); software used to prepare material for publication: publCIF (Westrip, 2009).
Supporting information
https://doi.org/10.1107/S1600536809038987/ci2886sup1.cif
contains datablocks I, glonal. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536809038987/ci2886Isup2.hkl
Single crystals of 1,3-difluorobenzene were grown from commerical samples by zone melting in a quartz capillary at 163 K according to the procedure outlined by Boese & Nussbaumer (1994).
H atoms were positioned geoemtrically (C-H = 0.95 or 0.96 Å) and refined using a riding model, with their isotropic displacement parameters set equal to 1.2 times Ueq of the corresponding carbon atom.
Despite the high δ±-Fδ- and the Hδ±-Cδ- 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 some of us had reported the crystal structures of several polyfluorinated benzenes in this connection (Thalladi et al., 1998). As a continuation of this work, we report here the of 1,3-difluorobenzene. The comparison crystal structures of 1,2- and 1,4-difluorobenzene and 1,3,5-trifluorobenzene have been reported in this earlier work.
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 CFor C—H···F interactions, see: Althoff et al. (2006); Bats et al. (2000); Choudhury et al. (2004); D'Oria & Novoa (2008); Dunitz & Taylor (1997); Howard et al. (1996); Müller et al. (2007); O'Hagan (2008); Reichenbacher et al. (2005); Weiss et al. (1997). For the crystal structures of polyfluorinated benzenes, see: Thalladi et al. (1998). For crystallization techniques, see: Boese & Nussbaumer (1994). Cg1 and Cg2 are the centroids of the C1–C6 and C11–C16 rings, respectively.
Data collection: APEX2 (Bruker, 2008); cell
SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008) and GIMP (The GIMP team, 2008); software used to prepare material for publication: publCIF (Westrip, 2009).Fig. 1. Crystal structure of 1,3-difluorobenzene: (a) two-dimensional network of C—H···F—C interactions viewed along the c axis, (b) with independent molecules coloured blue and green, (c) Herringbone arrangement of molecules viewed along the a axis and (d) coloured as before. | |
Fig. 2. Displacement ellipsoid plot of 1,3-difluorobenzene. |
C6H4F2 | F(000) = 928 |
Mr = 114.09 | Dx = 1.445 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 2977 reflections |
a = 24.6618 (13) Å | θ = 2.9–28.2° |
b = 12.2849 (5) Å | µ = 0.13 mm−1 |
c = 7.2336 (4) Å | T = 153 K |
β = 106.842 (3)° | Cylindric, colourless |
V = 2097.55 (18) Å3 | 0.30 × 0.30 × 0.30 mm |
Z = 16 |
Bruker SMART APEXII area-detector diffractometer | 2099 independent reflections |
Radiation source: fine-focus sealed tube | 1578 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.020 |
Detector resolution: 512 pixels mm-1 | θmax = 28.3°, θmin = 1.9° |
Data collection strategy APEX 2/COSMO with chi +/– 10° scans | h = −27→29 |
Absorption correction: multi-scan (SADABS; Bruker, 2004) | k = −16→16 |
Tmin = 0.876, Tmax = 0.961 | l = −9→8 |
7831 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.032 | H-atom parameters not refined |
wR(F2) = 0.100 | w = 1/[s2(Fo2) + (0.0494P)2 + 0.6228P] where P = (Fo2 + 2Fc2)/3 |
S = 1.01 | (Δ/σ)max = 0.001 |
2099 reflections | Δρmax = 0.19 e Å−3 |
146 parameters | Δρmin = −0.13 e Å−3 |
0 restraints | Extinction correction: SHELXTL (Bruker, 2008), Fc*=kFc[1+0.001xFc2λ3sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0034 (7) |
C6H4F2 | V = 2097.55 (18) Å3 |
Mr = 114.09 | Z = 16 |
Monoclinic, C2/c | Mo Kα radiation |
a = 24.6618 (13) Å | µ = 0.13 mm−1 |
b = 12.2849 (5) Å | T = 153 K |
c = 7.2336 (4) Å | 0.30 × 0.30 × 0.30 mm |
β = 106.842 (3)° |
Bruker SMART APEXII area-detector diffractometer | 2099 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2004) | 1578 reflections with I > 2σ(I) |
Tmin = 0.876, Tmax = 0.961 | Rint = 0.020 |
7831 measured reflections |
R[F2 > 2σ(F2)] = 0.032 | 0 restraints |
wR(F2) = 0.100 | H-atom parameters not refined |
S = 1.01 | Δρmax = 0.19 e Å−3 |
2099 reflections | Δρmin = −0.13 e Å−3 |
146 parameters |
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 F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
F1 | 0.20034 (3) | 0.21738 (6) | 0.63089 (12) | 0.0520 (3) | |
F2 | 0.01617 (3) | 0.35397 (7) | 0.49907 (14) | 0.0587 (3) | |
C1 | 0.16251 (5) | 0.29864 (9) | 0.56491 (16) | 0.0349 (3) | |
C2 | 0.10797 (6) | 0.28273 (9) | 0.56876 (17) | 0.0372 (3) | |
H2 | 0.0966 | 0.2170 | 0.6188 | 0.045* | |
C3 | 0.07043 (6) | 0.36645 (10) | 0.49742 (18) | 0.0370 (3) | |
C4 | 0.08585 (6) | 0.46202 (9) | 0.42616 (17) | 0.0378 (3) | |
H4 | 0.0586 | 0.5187 | 0.3775 | 0.045* | |
C5 | 0.14156 (6) | 0.47408 (9) | 0.42727 (16) | 0.0370 (3) | |
H5 | 0.1531 | 0.5394 | 0.3793 | 0.044* | |
C6 | 0.18102 (6) | 0.39238 (9) | 0.49720 (17) | 0.0355 (3) | |
H6 | 0.2199 | 0.4008 | 0.4989 | 0.043* | |
F11 | 0.23615 (3) | 0.09707 (6) | 0.01979 (13) | 0.0571 (3) | |
F12 | 0.05258 (4) | −0.03682 (6) | −0.08892 (13) | 0.0625 (3) | |
C11 | 0.18189 (6) | 0.11273 (10) | 0.01807 (17) | 0.0365 (3) | |
C12 | 0.14440 (6) | 0.02770 (9) | −0.03976 (17) | 0.0382 (3) | |
H12 | 0.1558 | −0.0409 | −0.0800 | 0.046* | |
C13 | 0.08994 (6) | 0.04613 (9) | −0.03803 (18) | 0.0385 (3) | |
C14 | 0.07131 (6) | 0.14411 (9) | 0.01511 (18) | 0.0380 (3) | |
H14 | 0.0325 | 0.1545 | 0.0122 | 0.046* | |
C15 | 0.11075 (6) | 0.22716 (9) | 0.07194 (17) | 0.0383 (3) | |
H15 | 0.0992 | 0.2961 | 0.1105 | 0.046* | |
C16 | 0.16634 (6) | 0.21260 (9) | 0.07456 (18) | 0.0392 (3) | |
H16 | 0.1934 | 0.2705 | 0.1133 | 0.047* |
U11 | U22 | U33 | U12 | U13 | U23 | |
F1 | 0.0441 (6) | 0.0416 (4) | 0.0679 (5) | 0.0105 (3) | 0.0124 (4) | 0.0059 (3) |
F2 | 0.0295 (6) | 0.0668 (5) | 0.0841 (6) | −0.0076 (4) | 0.0234 (5) | −0.0023 (4) |
C1 | 0.0343 (9) | 0.0338 (5) | 0.0352 (6) | 0.0013 (5) | 0.0078 (6) | −0.0017 (4) |
C2 | 0.0397 (9) | 0.0341 (6) | 0.0401 (6) | −0.0071 (5) | 0.0153 (6) | −0.0012 (4) |
C3 | 0.0257 (9) | 0.0455 (6) | 0.0411 (6) | −0.0062 (5) | 0.0118 (6) | −0.0064 (5) |
C4 | 0.0346 (9) | 0.0382 (6) | 0.0379 (6) | 0.0027 (5) | 0.0064 (6) | 0.0002 (5) |
C5 | 0.0405 (9) | 0.0351 (6) | 0.0362 (6) | −0.0046 (5) | 0.0123 (6) | 0.0017 (4) |
C6 | 0.0267 (9) | 0.0421 (6) | 0.0395 (6) | −0.0053 (5) | 0.0122 (6) | −0.0038 (5) |
F11 | 0.0289 (6) | 0.0654 (5) | 0.0794 (6) | 0.0116 (4) | 0.0195 (5) | 0.0076 (4) |
F12 | 0.0502 (6) | 0.0499 (5) | 0.0894 (6) | −0.0173 (4) | 0.0235 (5) | −0.0145 (4) |
C11 | 0.0242 (9) | 0.0468 (6) | 0.0392 (6) | 0.0077 (5) | 0.0100 (6) | 0.0073 (5) |
C12 | 0.0425 (9) | 0.0346 (6) | 0.0402 (6) | 0.0064 (5) | 0.0161 (6) | 0.0016 (5) |
C13 | 0.0370 (9) | 0.0375 (6) | 0.0416 (6) | −0.0045 (5) | 0.0122 (6) | −0.0014 (5) |
C14 | 0.0283 (9) | 0.0452 (6) | 0.0433 (7) | 0.0049 (5) | 0.0149 (6) | 0.0019 (5) |
C15 | 0.0403 (9) | 0.0357 (6) | 0.0409 (6) | 0.0049 (5) | 0.0150 (6) | −0.0018 (4) |
C16 | 0.0355 (9) | 0.0381 (6) | 0.0423 (7) | −0.0041 (5) | 0.0086 (6) | −0.0017 (5) |
F1—C1 | 1.3553 (13) | F11—C11 | 1.3486 (14) |
F2—C3 | 1.3506 (15) | F12—C13 | 1.3515 (14) |
C1—C2 | 1.3673 (18) | C11—C12 | 1.3773 (17) |
C1—C6 | 1.3797 (15) | C11—C16 | 1.3820 (16) |
C2—C3 | 1.3800 (17) | C12—C13 | 1.3656 (18) |
C2—H2 | 0.96 | C12—H12 | 0.96 |
C3—C4 | 1.3793 (16) | C13—C14 | 1.3821 (16) |
C4—C5 | 1.3794 (18) | C14—C15 | 1.3872 (17) |
C4—H4 | 0.96 | C14—H14 | 0.96 |
C5—C6 | 1.3874 (17) | C15—C16 | 1.3772 (18) |
C5—H5 | 0.95 | C15—H15 | 0.96 |
C6—H6 | 0.96 | C16—H16 | 0.96 |
F1—C1—C2 | 117.92 (10) | F11—C11—C12 | 118.14 (11) |
F1—C1—C6 | 118.36 (11) | F11—C11—C16 | 118.92 (11) |
C2—C1—C6 | 123.71 (11) | C12—C11—C16 | 122.94 (12) |
C1—C2—C3 | 116.30 (10) | C13—C12—C11 | 116.54 (11) |
C1—C2—H2 | 121.7 | C13—C12—H12 | 121.6 |
C3—C2—H2 | 122.0 | C11—C12—H12 | 121.8 |
F2—C3—C2 | 118.12 (10) | F12—C13—C12 | 117.85 (10) |
F2—C3—C4 | 118.76 (12) | F12—C13—C14 | 118.50 (11) |
C2—C3—C4 | 123.12 (12) | C12—C13—C14 | 123.65 (11) |
C3—C4—C5 | 118.11 (11) | C13—C14—C15 | 117.50 (12) |
C3—C4—H4 | 121.0 | C13—C14—H14 | 121.3 |
C5—C4—H4 | 120.9 | C15—C14—H14 | 121.2 |
C4—C5—C6 | 121.10 (11) | C16—C15—C14 | 121.22 (11) |
C4—C5—H5 | 119.5 | C16—C15—H15 | 119.3 |
C6—C5—H5 | 119.4 | C14—C15—H15 | 119.5 |
C1—C6—C5 | 117.64 (12) | C15—C16—C11 | 118.14 (11) |
C1—C6—H6 | 121.2 | C15—C16—H16 | 120.8 |
C5—C6—H6 | 121.2 | C11—C16—H16 | 121.0 |
D—H···A | D—H | H···A | D···A | D—H···A |
C2—H2···F12i | 0.96 | 2.72 | 3.3750 (14) | 126 |
C4—H4···F2ii | 0.96 | 2.76 | 3.5386 (16) | 139 |
C5—H5···F11iii | 0.95 | 2.71 | 3.2948 (16) | 121 |
C6—H6···F11iii | 0.96 | 2.66 | 3.2644 (15) | 121 |
C6—H6···F1iv | 0.96 | 2.82 | 3.5789 (17) | 137 |
C12—H12···F1v | 0.96 | 2.70 | 3.3919 (14) | 130 |
C14—H14···F2vi | 0.96 | 2.72 | 3.3442 (16) | 123 |
C14—H14···F12vii | 0.96 | 2.73 | 3.5075 (18) | 138 |
C15—H15···F2vi | 0.96 | 2.81 | 3.3995 (17) | 120 |
C16—H16···F11viii | 0.96 | 2.75 | 3.5591 (16) | 142 |
C2—H2···Cg2ix | 0.96 | 2.96 | 3.6653 (13) | 131 |
C12—H12···Cg2v | 0.96 | 2.99 | 3.6547 (13) | 127 |
C5—H5···Cg1x | 0.95 | 2.83 | 3.5153 (12) | 130 |
C15—H15···Cg1 | 0.96 | 2.87 | 3.5283 (13) | 127 |
Symmetry codes: (i) x, −y, z+1/2; (ii) −x, −y+1, −z+1; (iii) −x+1/2, y+1/2, −z+1/2; (iv) −x+1/2, −y+1/2, −z+1; (v) x, −y, z−1/2; (vi) −x, y, −z+1/2; (vii) −x, −y, −z; (viii) −x+1/2, −y+1/2, −z; (ix) x, y, z+1; (x) x, −y+1, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | C6H4F2 |
Mr | 114.09 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 153 |
a, b, c (Å) | 24.6618 (13), 12.2849 (5), 7.2336 (4) |
β (°) | 106.842 (3) |
V (Å3) | 2097.55 (18) |
Z | 16 |
Radiation type | Mo Kα |
µ (mm−1) | 0.13 |
Crystal size (mm) | 0.30 × 0.30 × 0.30 |
Data collection | |
Diffractometer | Bruker SMART APEXII area-detector |
Absorption correction | Multi-scan (SADABS; Bruker, 2004) |
Tmin, Tmax | 0.876, 0.961 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 7831, 2099, 1578 |
Rint | 0.020 |
(sin θ/λ)max (Å−1) | 0.667 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.032, 0.100, 1.01 |
No. of reflections | 2099 |
No. of parameters | 146 |
H-atom treatment | H-atom parameters not refined |
Δρmax, Δρmin (e Å−3) | 0.19, −0.13 |
Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXTL (Sheldrick, 2008), Mercury (Macrae et al., 2008) and GIMP (The GIMP team, 2008), publCIF (Westrip, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
C2—H2···F12i | 0.96 | 2.72 | 3.3750 (14) | 126 |
C4—H4···F2ii | 0.96 | 2.76 | 3.5386 (16) | 139 |
C5—H5···F11iii | 0.95 | 2.71 | 3.2948 (16) | 121 |
C6—H6···F11iii | 0.96 | 2.66 | 3.2644 (15) | 121 |
C6—H6···F1iv | 0.96 | 2.82 | 3.5789 (17) | 137 |
C12—H12···F1v | 0.96 | 2.70 | 3.3919 (14) | 130 |
C14—H14···F2vi | 0.96 | 2.72 | 3.3442 (16) | 123 |
C14—H14···F12vii | 0.96 | 2.73 | 3.5075 (18) | 138 |
C15—H15···F2vi | 0.96 | 2.81 | 3.3995 (17) | 120 |
C16—H16···F11viii | 0.96 | 2.75 | 3.5591 (16) | 142 |
C2—H2···Cg2ix | 0.96 | 2.96 | 3.6653 (13) | 131 |
C12—H12···Cg2v | 0.96 | 2.99 | 3.6547 (13) | 127 |
C5—H5···Cg1x | 0.95 | 2.83 | 3.5153 (12) | 130 |
C15—H15···Cg1 | 0.96 | 2.87 | 3.5283 (13) | 127 |
Symmetry codes: (i) x, −y, z+1/2; (ii) −x, −y+1, −z+1; (iii) −x+1/2, y+1/2, −z+1/2; (iv) −x+1/2, −y+1/2, −z+1; (v) x, −y, z−1/2; (vi) −x, y, −z+1/2; (vii) −x, −y, −z; (viii) −x+1/2, −y+1/2, −z; (ix) x, y, z+1; (x) x, −y+1, z−1/2. |
Acknowledgements
MTK and RB thank the DFG FOR-618. GRD thanks the DST for the award of a J.C. Bose fellowship. TST thanks the UGC for an SRF.
References
Althoff, G., Ruiz, J., Rodriguez, V., Lopez, G., Perez, J. & Janiak, C. (2006). CrystEngComm, 8, 662–665. Web of Science CSD CrossRef CAS Google Scholar
Bats, J. W., Parsch, J. & Engels, J. W. (2000). Acta Cryst. C56, 201–205. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Boese, R. & Nussbaumer, M. (1994). In Situ Crystallisation Techniques. In Organic Crystal Chemistry, edited by D. W. Jones, pp. 20–37. Oxford University Press. Google Scholar
Bruker (2004). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Choudhury, A. R., Nagarajan, K. & Guru Row, T. N. (2004). Acta Cryst. C60, o644–o647. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
D'Oria, E. & Novoa, J. J. (2008). CrystEngComm, 10, 423–436. CAS Google Scholar
Dunitz, J. D. & Taylor, R. (1997). Chem. Eur. J. 3, 89–98. CrossRef CAS Web of Science Google Scholar
Howard, J. A. K., Hoy, V. J., O'Hagan, D. & Smith, G. T. (1996). Tetrahedron, 38, 12613–12622. CrossRef Web of Science Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Müller, K., Faeh, C. & Diederich, F. (2007). Science, 317, 1881–1886. Web of Science PubMed Google Scholar
O'Hagan, D. (2008). Chem. Soc. Rev. 37, 308–319. Web of Science CrossRef PubMed CAS Google Scholar
Reichenbacher, K., Suss, H. I. & Hulliger, J. (2005). J. Chem. Soc. Rev. 34, 22–30. Web of Science CrossRef Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Thalladi, V. R., Weiss, H. C., Bläser, D., Boese, R., Nangia, A. & Desiraju, G. R. (1998). J. Am. Chem. Soc. 120, 8702–8710. Web of Science CSD CrossRef CAS Google Scholar
The GIMP team (2008). The GNU Image Manipulation Program, http://www.gimp.org. Google Scholar
Weiss, H. C., Boese, R., Smith, H. L. & Haley, M. M. (1997). Chem. Commun. pp. 2403–2404. Web of Science CSD CrossRef Google Scholar
Westrip, S. P. (2009). publCIF. In preparation. Google Scholar
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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 Cδ±-Fδ- and the Hδ±-Cδ- 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 some of us had reported the crystal structures of several polyfluorinated benzenes in this connection (Thalladi et al., 1998). As a continuation of this work, we report here the crystal structure of 1,3-difluorobenzene. The comparison crystal structures of 1,2- and 1,4-difluorobenzene and 1,3,5-trifluorobenzene have been reported in this earlier work.