Buy article online - an online subscription or single-article purchase is required to access this article.
Download citation
Download citation
link to html
The title compound, C8H8Br4, displays crystallographic inversion symmetry. The packing involves inter­penetrating corrugated layers built up via Br...Br and Br...π contacts.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805018374/bt6681sup1.cif
Contains datablocks 2, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536805018374/bt66812sup2.hkl
Contains datablock 2

CCDC reference: 277209

Key indicators

  • Single-crystal X-ray study
  • T = 173 K
  • Mean [sigma](C-C) = 0.011 Å
  • R factor = 0.041
  • wR factor = 0.105
  • Data-to-parameter ratio = 16.1

checkCIF/PLATON results

No syntax errors found



Alert level A ABSTM02_ALERT_3_A Crystal and compound unsuitable for non-numerical corrections. Product of mu and tmid > 3.0 Value of mu given = 14.961 tmid = 0.300 PLAT060_ALERT_3_A Ratio Tmax/Tmin (Exp-to-Rep) (too) Large ....... 5.22 PLAT065_ALERT_3_A Crystal Requires Numerical Correction mu*tmid .. 4.49
Alert level B PLAT029_ALERT_3_B _diffrn_measured_fraction_theta_full Low ....... 0.96
Alert level C PLAT062_ALERT_4_C Rescale T(min) & T(max) by ..................... 0.11 PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given ....... ? PLAT341_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ... 11 PLAT431_ALERT_2_C Short Inter HL..A Contact Br2 .. Br2 .. 3.50 Ang.
3 ALERT level A = In general: serious problem 1 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 5 ALERT type 3 Indicator that the structure quality may be low 2 ALERT type 4 Improvement, methodology, query or suggestion

Computing details top

Data collection: XSCANS (Fait, 1991); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP5 (Siemens, 1994); software used to prepare material for publication: SHELXL97.

1,4-Bis(dibromomethylidene)cyclohexane top
Crystal data top
C8H8Br4F(000) = 392
Mr = 423.78Dx = 2.626 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 6.6033 (10) ÅCell parameters from 62 reflections
b = 12.3957 (18) Åθ = 3.5–12.5°
c = 6.7152 (10) ŵ = 14.96 mm1
β = 102.783 (12)°T = 173 K
V = 536.03 (14) Å3Tablet, colourless
Z = 20.4 × 0.3 × 0.15 mm
Data collection top
Siemens P4
diffractometer
738 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.076
Graphite monochromatorθmax = 25.0°, θmin = 3.3°
ω scansh = 77
Absorption correction: ψ scan
(XEMP; Siemens, 1994)
k = 014
Tmin = 0.30, Tmax = 0.95l = 07
973 measured reflections3 standard reflections every 247 reflections
901 independent reflections intensity decay: none
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.042H-atom parameters constrained
wR(F2) = 0.105 w = 1/[σ2(Fo2) + (0.064P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.13(Δ/σ)max < 0.001
901 reflectionsΔρmax = 0.96 e Å3
56 parametersΔρmin = 0.71 e Å3
5 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.043 (4)
Special details top

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.

Short contacts:

3.4956 (0.0015) Br2 - Br2_$2 3.9051 (0.0012) Br1 - Br2_$3 3.3955 (0.0072) C1 - Br1_$4 3.4054 (0.0076) C2 - Br1_$4

151.96 (0.24) C1 - Br2 - Br2_$2 143.87 (0.21) C1 - Br1 - Br2_$3 60.39 (0.22) Br1 - Br2_$3 - C1_$3

Operators for generating equivalent atoms: $2 - x, -y + 1, -z + 1 $3 x + 1/2, -y + 1/2, z + 1/2 $4 x - 1/2, -y + 1/2, z - 1/2

=============================================================================

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

2.9634 (0.0109) x + 9.0710 (0.0156) y + 2.6922 (0.0115) z = 5.4894 (0.0025)

* 0.0249 (0.0034) Br1 * -0.0322 (0.0035) Br2 * 0.0040 (0.0061) C1 * 0.0181 (0.0070) C2 * 0.0283 (0.0044) C3 * -0.0430 (0.0043) C4_$1

Rms deviation of fitted atoms = 0.0279

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 (Å2) top
xyzUiso*/Ueq
Br10.59085 (13)0.27787 (7)0.46164 (13)0.0310 (3)
Br20.18311 (11)0.41201 (7)0.43723 (12)0.0272 (3)
C10.4057 (11)0.3809 (6)0.3106 (11)0.0200 (16)
C20.4294 (11)0.4255 (6)0.1393 (12)0.0207 (16)
C30.2849 (11)0.5080 (7)0.0242 (11)0.0247 (16)
H3A0.18840.53200.10910.030*
H3B0.20120.47470.10130.030*
C40.3993 (11)0.6060 (7)0.0343 (12)0.0269 (17)
H4A0.29900.65310.12630.032*
H4B0.45950.64790.09030.032*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0337 (5)0.0274 (5)0.0331 (5)0.0081 (4)0.0100 (4)0.0113 (4)
Br20.0293 (5)0.0273 (5)0.0287 (5)0.0018 (3)0.0146 (3)0.0020 (3)
C10.021 (3)0.018 (4)0.021 (4)0.000 (3)0.006 (3)0.003 (3)
C20.017 (3)0.020 (4)0.024 (4)0.002 (3)0.002 (3)0.001 (3)
C30.021 (3)0.027 (4)0.026 (4)0.006 (3)0.006 (3)0.004 (3)
C40.026 (4)0.025 (4)0.030 (4)0.009 (3)0.009 (3)0.004 (4)
Geometric parameters (Å, º) top
Br1—C11.899 (7)C3—C41.527 (11)
Br2—C11.894 (7)C3—H3A0.9900
C1—C21.316 (11)C3—H3B0.9900
C2—C31.492 (11)C4—H4A0.9900
C2—C4i1.510 (10)C4—H4B0.9900
C2—C1—Br2124.1 (6)C2—C3—H3B109.1
C2—C1—Br1124.2 (6)C4—C3—H3B109.1
Br2—C1—Br1111.7 (4)H3A—C3—H3B107.8
C1—C2—C3123.7 (7)C2i—C4—C3112.3 (7)
C1—C2—C4i123.0 (7)C2i—C4—H4A109.2
C3—C2—C4i113.2 (6)C3—C4—H4A109.2
C2—C3—C4112.5 (6)C2i—C4—H4B109.2
C2—C3—H3A109.1C3—C4—H4B109.2
C4—C3—H3A109.1H4A—C4—H4B107.9
Br2—C1—C2—C31.0 (12)C1—C2—C3—C4131.4 (8)
Br1—C1—C2—C3178.8 (6)C4i—C2—C3—C451.4 (10)
Br2—C1—C2—C4i175.9 (6)C2—C3—C4—C2i50.9 (10)
Br1—C1—C2—C4i4.3 (11)C3—C4—C2—C3i51.3 (10)
Symmetry code: (i) x+1, y+1, z.
 

Subscribe to Acta Crystallographica Section E: Crystallographic Communications

The full text of this article is available to subscribers to the journal.

If you have already registered and are using a computer listed in your registration details, please email support@iucr.org for assistance.

Buy online

You may purchase this article in PDF and/or HTML formats. For purchasers in the European Community who do not have a VAT number, VAT will be added at the local rate. Payments to the IUCr are handled by WorldPay, who will accept payment by credit card in several currencies. To purchase the article, please complete the form below (fields marked * are required), and then click on `Continue'.
E-mail address* 
Repeat e-mail address* 
(for error checking) 

Format*   PDF (US $40)
   HTML (US $40)
   PDF+HTML (US $50)
In order for VAT to be shown for your country javascript needs to be enabled.

VAT number 
(non-UK EC countries only) 
Country* 
 

Terms and conditions of use
Contact us

Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds