2,3-Difluoro-benzoic acid.

2,3-Difluoro-benzoic acid, C(7)H(4)F(2)O(2), forms dimers that are stabilized by hydrogen bonds. The dimers are stacked and the stacks are held together by weak C-H⋯F and C-H⋯O inter-actions.

Related literature

For related literature, see: Juhler & Mortensen (2002 ▶); Malone et al. (2006 ▶); Potrzebowski & Chruszcz (2007 ▶).

Experimental

Crystal data

C7H4F2O2

M = 158.10

Monoclinic,

a = 3.761 (1) Å

b = 6.520 (1) Å

c = 26.521 (2) Å

β = 92.27 (1)°

V = 649.8 (2) Å3

Z = 4

Mo Kα radiation

μ = 0.15 mm−1

T = 293 (2) K

0.15 × 0.15 × 0.02 mm

Data collection

Rigaku R-AXIS RAPID diffractometer

Absorption correction: multi-scan (Otwinowski et al., 2003 ▶) T min = 0.98, T max = 1.00 (expected range = 0.977–0.997)

25713 measured reflections

1881 independent reflections

1371 reflections with I > 2σ(I)

R int = 0.031

Refinement

R[F 2 > 2σ(F 2)] = 0.043

wR(F 2) = 0.133

S = 1.06

1881 reflections

116 parameters

All H-atom parameters refined

Δρmax = 0.28 e Å−3

Δρmin = −0.13 e Å−3

Data collection: HKL-2000 (Otwinowski & Minor, 1997 ▶); cell refinement: HKL-2000; data reduction: HKL-2000; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶) and HKL-3000SM (Minor et al., 2006 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶) and HKL-3000SM; molecular graphics: HKL-3000SM, Mercury (Macrae et al., 2006 ▶), ORTEPIII (Burnett & Johnson, 1996 ▶) and ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: HKL-3000SM.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808001232/om2199sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808001232/om2199Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C7H4F2O2	F000 = 320
Mr = 158.10	Dx = 1.616 Mg m−3
Monoclinic, P21/c	Mo Kα radiation λ = 0.71074 Å
Hall symbol: -P 2ybc	Cell parameters from 25713 reflections
a = 3.761 (1) Å	θ = 3.1–30.0º
b = 6.520 (1) Å	µ = 0.15 mm−1
c = 26.521 (2) Å	T = 293 (2) K
β = 92.27 (1)º	Plate, colorless
V = 649.8 (2) Å3	0.15 × 0.15 × 0.02 mm
Z = 4

Rigaku R-AXIS RAPID diffractometer	1881 independent reflections
Radiation source: fine-focus sealed tube	1371 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.031
Detector resolution: 10 pixels mm-1	θmax = 30.0º
T = 293(2) K	θmin = 3.1º
ω scans with χ offset	h = −5→5
Absorption correction: multi-scan(Otwinowski et al., 2003)	k = −9→9
Tmin = 0.98, Tmax = 1.00	l = −37→37
25713 measured reflections

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.044	All H-atom parameters refined
wR(F2) = 0.133	w = 1/[σ2(Fo2) + (0.0665P)2 + 0.0891P] where P = (Fo2 + 2Fc2)/3
S = 1.06	(Δ/σ)max < 0.001
1881 reflections	Δρmax = 0.29 e Å−3
116 parameters	Δρmin = −0.13 e Å−3
Primary atom site location: structure-invariant direct methods	Extinction correction: none

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
C1	0.3028 (3)	0.18896 (18)	0.09787 (4)	0.0453 (3)
C2	0.3710 (3)	0.2435 (2)	0.14793 (5)	0.0507 (3)
C3	0.2895 (4)	0.1088 (2)	0.18600 (5)	0.0580 (3)
C4	0.1428 (4)	−0.0797 (2)	0.17592 (6)	0.0607 (4)
C5	0.0737 (4)	−0.1357 (2)	0.12626 (6)	0.0587 (3)
C6	0.1521 (3)	−0.0033 (2)	0.08785 (5)	0.0517 (3)
C7	0.3892 (3)	0.32666 (19)	0.05550 (5)	0.0485 (3)
F1	0.5159 (3)	0.42443 (14)	0.16134 (3)	0.0748 (3)
F2	0.3611 (3)	0.16829 (19)	0.23412 (3)	0.0893 (4)
O1	0.5592 (3)	0.48801 (16)	0.06313 (4)	0.0673 (3)
O2	0.2818 (3)	0.26822 (19)	0.01143 (4)	0.0742 (4)
H2	0.330 (8)	0.372 (4)	−0.0169 (13)	0.158 (11)*
H4	0.090 (5)	−0.174 (3)	0.2020 (8)	0.087 (6)*
H5	−0.026 (5)	−0.264 (3)	0.1183 (7)	0.079 (5)*
H6	0.104 (4)	−0.037 (3)	0.0534 (6)	0.057 (4)*

	U11	U22	U33	U12	U13	U23
C1	0.0441 (6)	0.0446 (6)	0.0472 (6)	0.0012 (5)	0.0014 (4)	−0.0005 (5)
C2	0.0550 (7)	0.0465 (6)	0.0503 (6)	0.0009 (5)	0.0003 (5)	−0.0037 (5)
C3	0.0635 (8)	0.0653 (8)	0.0451 (6)	0.0066 (6)	0.0024 (5)	0.0018 (6)
C4	0.0593 (7)	0.0625 (8)	0.0607 (8)	0.0018 (6)	0.0074 (6)	0.0151 (6)
C5	0.0565 (7)	0.0494 (7)	0.0699 (9)	−0.0047 (6)	0.0003 (6)	0.0058 (6)
C6	0.0524 (7)	0.0495 (7)	0.0529 (7)	−0.0036 (5)	−0.0017 (5)	−0.0021 (5)
C7	0.0503 (6)	0.0481 (6)	0.0471 (6)	−0.0027 (5)	0.0001 (5)	−0.0024 (5)
F1	0.1091 (7)	0.0572 (5)	0.0576 (5)	−0.0162 (5)	−0.0039 (5)	−0.0095 (4)
F2	0.1270 (9)	0.0956 (8)	0.0449 (5)	−0.0067 (7)	0.0015 (5)	−0.0011 (5)
O1	0.0901 (7)	0.0569 (6)	0.0544 (5)	−0.0240 (5)	−0.0021 (5)	0.0016 (4)
O2	0.1028 (9)	0.0728 (7)	0.0461 (5)	−0.0317 (6)	−0.0058 (5)	0.0013 (5)

C1—C2	1.3885 (17)	C4—H4	0.95 (2)
C1—C6	1.3968 (17)	C5—C6	1.376 (2)
C1—C7	1.4842 (17)	C5—H5	0.94 (2)
C2—F1	1.3415 (16)	C6—H6	0.950 (16)
C2—C3	1.3819 (19)	C7—O1	1.2435 (16)
C3—F2	1.3508 (16)	C7—O2	1.2796 (15)
C3—C4	1.369 (2)	O2—H2	1.03 (3)
C4—C5	1.381 (2)
C2—C1—C6	118.03 (12)	C5—C4—H4	119.0 (12)
C2—C1—C7	122.09 (11)	C6—C5—C4	120.17 (14)
C6—C1—C7	119.88 (11)	C6—C5—H5	119.2 (12)
F1—C2—C3	117.71 (12)	C4—C5—H5	120.6 (11)
F1—C2—C1	122.43 (12)	C5—C6—C1	121.28 (13)
C3—C2—C1	119.86 (12)	C5—C6—H6	122.0 (10)
F2—C3—C4	120.41 (13)	C1—C6—H6	116.8 (10)
F2—C3—C2	117.76 (14)	O1—C7—O2	122.84 (12)
C4—C3—C2	121.82 (13)	O1—C7—C1	121.00 (11)
C3—C4—C5	118.84 (13)	O2—C7—C1	116.15 (11)
C3—C4—H4	122.2 (12)	C7—O2—H2	114.3 (16)
C6—C1—C2—F1	179.84 (11)	C2—C3—C4—C5	−0.2 (2)
C7—C1—C2—F1	0.6 (2)	C3—C4—C5—C6	0.0 (2)
C6—C1—C2—C3	−0.03 (19)	C4—C5—C6—C1	0.2 (2)
C7—C1—C2—C3	−179.23 (12)	C2—C1—C6—C5	−0.17 (19)
F1—C2—C3—F2	0.0 (2)	C7—C1—C6—C5	179.05 (12)
C1—C2—C3—F2	179.88 (12)	C2—C1—C7—O1	7.3 (2)
F1—C2—C3—C4	−179.64 (13)	C6—C1—C7—O1	−171.85 (12)
C1—C2—C3—C4	0.2 (2)	C2—C1—C7—O2	−173.28 (12)
F2—C3—C4—C5	−179.87 (13)	C6—C1—C7—O2	7.53 (18)

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···O1i	0.94 (2)	2.65 (2)	3.509 (2)	153 (2)
O2—H2···O1ii	1.03 (3)	1.60 (3)	2.625 (2)	173 (3)
C6—H6···O2iii	0.95 (2)	2.67 (2)	3.498 (2)	146 (1)
C4—H4···F2iv	0.95 (2)	2.65 (2)	3.513 (2)	151 (2)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯O1i	0.94 (2)	2.65 (2)	3.509 (2)	153 (2)
O2—H2⋯O1ii	1.03 (3)	1.60 (3)	2.625 (2)	173 (3)
C6—H6⋯O2iii	0.95 (2)	2.67 (2)	3.498 (2)	146 (1)
C4—H4⋯F2iv	0.95 (2)	2.65 (2)	3.513 (2)	151 (2)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) .