1,1-Bis(bromomethyl)benzene

In the crystal structure of the title mol­ecule, C₈H₈Br₂, there is a single C—H...π(arene) inter­action.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.007 Å
• R factor = 0.050
• wR factor = 0.135
• Data-to-parameter ratio = 21.2

checkCIF/PLATON results

No syntax errors found



Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR) is > 1.10
            Tmin and Tmax reported:      0.151     0.406
            Tmin and Tmax expected:      0.129     0.406
            RR =      1.172
            Please check that your absorption correction is appropriate.
PLAT060_ALERT_3_C Ratio Tmax/Tmin (Exp-to-Rep) (too) Large .......       1.14
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         C7
PLAT341_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          7

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2000); software used to prepare material for publication: SHELXTL.

1,1-Dibromo-m-xylene

Crystal data

C8H8Br2	F(000) = 504
Mr = 263.96	Dx = 1.963 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 1879 reflections
a = 13.084 (2) Å	θ = 2.7–25.2°
b = 4.5374 (8) Å	µ = 9.00 mm^−1
c = 15.075 (3) Å	T = 298 K
β = 93.846 (3)°	Plate, colorless
V = 893.0 (3) Å^3	0.30 × 0.20 × 0.10 mm
Z = 4

Data collection

Bruker SMART CCD diffractometer	1933 independent reflections
Radiation source: fine-focus sealed tube	1221 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.059
φ and ω scans	θmax = 27.0°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −16→16
Tmin = 0.151, Tmax = 0.406	k = −5→5
6118 measured reflections	l = −15→19

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.135	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0726P)^2] where P = (Fo^2 + 2Fc^2)/3
1933 reflections	(Δ/σ)max = 0.001
91 parameters	Δρmax = 0.75 e Å^−3
0 restraints	Δρmin = −0.52 e Å^−3

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Br1	1.14084 (4)	0.13612 (12)	0.54062 (4)	0.0657 (3)
Br2	0.78109 (4)	−0.11695 (13)	0.88989 (4)	0.0714 (3)
C1	1.0528 (4)	0.2013 (10)	0.7084 (3)	0.0485 (12)
C2	0.9747 (3)	0.0101 (10)	0.7284 (3)	0.0472 (12)
H2	0.9224	−0.0293	0.6852	0.057*
C3	0.9724 (4)	−0.1217 (9)	0.8098 (4)	0.0495 (12)
C4	1.0508 (4)	−0.0605 (12)	0.8732 (4)	0.0632 (14)
H4	1.0511	−0.1488	0.9289	0.076*
C5	1.1285 (4)	0.1305 (12)	0.8546 (4)	0.0684 (16)
H5	1.1806	0.1726	0.8977	0.082*
C6	1.1286 (4)	0.2572 (13)	0.7726 (4)	0.0623 (14)
H6	1.1814	0.3846	0.7602	0.075*
C7	1.0501 (5)	0.3407 (12)	0.6194 (4)	0.0758 (18)
H7A	1.0712	0.5451	0.6257	0.091*
H7B	0.9805	0.3372	0.5929	0.091*
C8	0.8883 (4)	−0.3254 (12)	0.8302 (5)	0.0717 (17)
H8A	0.9157	−0.4834	0.8681	0.086*
H8B	0.8591	−0.4124	0.7754	0.086*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0676 (4)	0.0718 (4)	0.0609 (4)	0.0019 (3)	0.0273 (3)	0.0036 (3)
Br2	0.0634 (4)	0.0832 (5)	0.0705 (5)	−0.0103 (3)	0.0271 (3)	−0.0021 (3)
C1	0.058 (3)	0.038 (2)	0.053 (3)	0.010 (2)	0.022 (2)	−0.002 (2)
C2	0.046 (2)	0.044 (3)	0.052 (3)	0.009 (2)	0.010 (2)	−0.007 (3)
C3	0.057 (3)	0.041 (3)	0.053 (3)	0.005 (2)	0.018 (2)	−0.003 (2)
C4	0.071 (3)	0.066 (3)	0.055 (4)	0.016 (3)	0.014 (3)	0.006 (3)
C5	0.055 (3)	0.089 (4)	0.061 (4)	0.002 (3)	−0.001 (3)	−0.012 (3)
C6	0.051 (3)	0.055 (3)	0.083 (4)	−0.006 (2)	0.020 (3)	−0.010 (3)
C7	0.095 (4)	0.057 (3)	0.080 (5)	0.023 (3)	0.039 (4)	0.015 (3)
C8	0.082 (4)	0.054 (3)	0.083 (5)	−0.005 (3)	0.037 (3)	−0.009 (3)

Geometric parameters (Å, º)

Br1—C7	1.967 (5)	C4—C5	1.379 (7)
Br2—C8	1.961 (5)	C4—H4	0.9300
C1—C6	1.362 (7)	C5—C6	1.363 (8)
C1—C2	1.389 (6)	C5—H5	0.9300
C1—C7	1.482 (7)	C6—H6	0.9300
C2—C3	1.367 (7)	C7—H7A	0.9700
C2—H2	0.9300	C7—H7B	0.9700
C3—C4	1.383 (7)	C8—H8A	0.9700
C3—C8	1.485 (7)	C8—H8B	0.9700
C6—C1—C2	118.3 (5)	C1—C6—C5	121.4 (5)
C6—C1—C7	122.4 (5)	C1—C6—H6	119.3
C2—C1—C7	119.4 (5)	C5—C6—H6	119.3
C3—C2—C1	121.9 (5)	C1—C7—Br1	111.5 (3)
C3—C2—H2	119.0	C1—C7—H7A	109.3
C1—C2—H2	119.0	Br1—C7—H7A	109.3
C2—C3—C4	118.2 (5)	C1—C7—H7B	109.3
C2—C3—C8	121.3 (5)	Br1—C7—H7B	109.3
C4—C3—C8	120.5 (5)	H7A—C7—H7B	108.0
C5—C4—C3	120.5 (5)	C3—C8—Br2	111.0 (3)
C5—C4—H4	119.7	C3—C8—H8A	109.4
C3—C4—H4	119.7	Br2—C8—H8A	109.4
C6—C5—C4	119.7 (5)	C3—C8—H8B	109.4
C6—C5—H5	120.2	Br2—C8—H8B	109.4
C4—C5—H5	120.2	H8A—C8—H8B	108.0
C6—C1—C2—C3	−0.2 (7)	C2—C1—C6—C5	−0.1 (8)
C7—C1—C2—C3	−179.1 (4)	C7—C1—C6—C5	178.8 (5)
C1—C2—C3—C4	0.0 (6)	C4—C5—C6—C1	0.5 (8)
C1—C2—C3—C8	180.0 (4)	C6—C1—C7—Br1	81.3 (6)
C2—C3—C4—C5	0.5 (7)	C2—C1—C7—Br1	−99.9 (5)
C8—C3—C4—C5	−179.5 (5)	C2—C3—C8—Br2	−95.4 (5)
C3—C4—C5—C6	−0.7 (8)	C4—C3—C8—Br2	84.6 (5)