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The X-ray crystal structure of hexaiodobenzene, C6I6, is reported with greatly improved precision after redetermination at 100 K. The compound is isostructural with hexachlorobenzene and hexabromobenzene. The molecule lies on an inversion centre.
Supporting information
CCDC reference: 636156
Key indicators
- Single-crystal X-ray study
- T = 100 K
- Mean (C-C) = 0.007 Å
- R factor = 0.022
- wR factor = 0.052
- Data-to-parameter ratio = 20.8
checkCIF/PLATON results
No syntax errors found
Alert level C
PLAT040_ALERT_1_C No H-atoms in this Carbon Containing Compound .. ?
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
1 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
0 ALERT type 2 Indicator that the structure model may be wrong or deficient
0 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
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.
Crystal data top
C6I6 | F(000) = 708 |
Mr = 833.46 | Dx = 4.600 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 3336 reflections |
a = 8.8100 (12) Å | θ = 2.3–26.0° |
b = 4.2247 (6) Å | µ = 15.44 mm−1 |
c = 16.191 (2) Å | T = 100 K |
β = 93.235 (2)° | Needle, yellow |
V = 601.67 (14) Å3 | 0.56 × 0.15 × 0.13 mm |
Z = 2 | |
Data collection top
Bruker SMART CCD diffractometer | 1163 independent reflections |
Radiation source: fine-focus sealed tube | 1148 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.023 |
φ and ω scans | θmax = 26.0°, θmin = 2.5° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −10→10 |
Tmin = 0.057, Tmax = 0.134 | k = −5→4 |
3375 measured reflections | l = −19→19 |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.022 | w = 1/[σ2(Fo2) + (0.023P)2 + 1.6335P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.052 | (Δ/σ)max = 0.003 |
S = 1.24 | Δρmax = 1.05 e Å−3 |
1163 reflections | Δρmin = −1.27 e Å−3 |
56 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.00171 (15) |
Special details top
Experimental. Crystals of C6I6 were grown by sublimation |
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 (Å2) top | x | y | z | Uiso*/Ueq | |
I1 | 1.07710 (3) | 0.10151 (8) | 0.791666 (17) | 0.01159 (12) | |
I2 | 0.72574 (3) | 0.33793 (8) | 0.860987 (18) | 0.01262 (12) | |
I3 | 0.65380 (3) | 0.26673 (8) | 1.071180 (17) | 0.01245 (12) | |
C2 | 0.8914 (5) | 0.1404 (11) | 0.9454 (3) | 0.0095 (9) | |
C3 | 0.8622 (5) | 0.1050 (11) | 1.0291 (3) | 0.0090 (9) | |
C1 | 1.0280 (5) | 0.0364 (12) | 0.9162 (3) | 0.0103 (9) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
I1 | 0.01087 (18) | 0.0157 (2) | 0.00845 (18) | 0.00001 (12) | 0.00271 (12) | 0.00084 (11) |
I2 | 0.01108 (18) | 0.0162 (2) | 0.01062 (18) | 0.00383 (12) | 0.00110 (12) | 0.00204 (12) |
I3 | 0.00953 (18) | 0.0173 (2) | 0.01070 (18) | 0.00312 (11) | 0.00235 (13) | −0.00121 (12) |
C2 | 0.010 (2) | 0.009 (2) | 0.010 (2) | 0.0007 (18) | −0.0009 (17) | 0.0015 (18) |
C3 | 0.007 (2) | 0.007 (2) | 0.012 (2) | 0.0006 (18) | 0.0024 (17) | −0.0023 (18) |
C1 | 0.011 (2) | 0.011 (2) | 0.009 (2) | −0.0030 (19) | 0.0018 (17) | −0.0004 (18) |
Geometric parameters (Å, º) top
I1—C1 | 2.104 (5) | C2—C3 | 1.401 (7) |
I2—C2 | 2.114 (5) | C3—C1i | 1.408 (6) |
I3—C3 | 2.108 (5) | C1—C3i | 1.408 (6) |
C2—C1 | 1.389 (7) | | |
| | | |
C1—C2—C3 | 120.3 (4) | C1i—C3—I3 | 120.9 (3) |
C1—C2—I2 | 119.0 (3) | C2—C1—C3i | 119.9 (4) |
C3—C2—I2 | 120.6 (3) | C2—C1—I1 | 120.9 (3) |
C2—C3—C1i | 119.8 (4) | C3i—C1—I1 | 119.2 (3) |
C2—C3—I3 | 119.2 (3) | | |
Symmetry code: (i) −x+2, −y, −z+2. |
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