2,4,6-Tri­chloroiodo­benzene

The crystal structure of 2,4,6-tri­chloro­iodo­benzene, C₆H₂Cl₃I, a precursor of polychlorinated bi­phenyls (PCBs), is described.

Key indicators

• Single-crystal X-ray study
• T = 90 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.021
• wR factor = 0.052
• Data-to-parameter ratio = 20.8

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          1
              C6 H2 Cl3 I

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 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
   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
   2 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: COLLECT (Nonius, 1998); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO-SMN (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL/PC (Sheldrick, 1994); software used to prepare material for publication: SHELX97-2 (Sheldrick, 1997) and local programs.

2,4,6-Trichloro-1-iodobenzene

Crystal data

C6H2Cl3I	F(000) = 568
Mr = 307.33	Dx = 2.472 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 3.9970 (1) Å	Cell parameters from 1946 reflections
b = 21.5840 (4) Å	θ = 1.0–27.5°
c = 9.7510 (2) Å	µ = 4.76 mm^−1
β = 100.994 (1)°	T = 90 K
V = 825.79 (3) Å^3	Block, colourless
Z = 4	0.15 × 0.10 × 0.10 mm

Data collection

Nonius KappaCCD diffractometer	1891 independent reflections
Radiation source: fine-focus sealed tube	1689 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.019
Detector resolution: 18 pixels mm^-1	θmax = 27.5°, θmin = 1.9°
ω scans at fixed χ = 55°	h = −5→5
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997)	k = −27→27
Tmin = 0.514, Tmax = 0.621	l = −12→12
3722 measured reflections

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)] = 0.021	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.052	H-atom parameters constrained
S = 1.10	w = 1/[σ^2(Fo^2) + (0.0246P)^2 + 0.3565P] where P = (Fo^2 + 2Fc^2)/3
1891 reflections	(Δ/σ)max = 0.001
91 parameters	Δρmax = 0.88 e Å^−3
0 restraints	Δρmin = −0.84 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
I1	0.86618 (4)	0.144598 (8)	0.012742 (16)	0.01723 (8)
Cl1	0.70450 (17)	0.00855 (3)	−0.15938 (7)	0.02172 (15)
Cl2	−0.08073 (17)	0.10503 (3)	−0.61485 (6)	0.02019 (15)
Cl3	0.46807 (17)	0.25731 (3)	−0.19849 (6)	0.02093 (15)
C1	0.5709 (6)	0.13230 (12)	−0.1860 (3)	0.0146 (5)
C2	0.5200 (6)	0.07368 (12)	−0.2463 (3)	0.0152 (5)
C3	0.3201 (6)	0.06479 (12)	−0.3776 (3)	0.0167 (5)
H3	0.2882	0.0245	−0.4171	0.020*
C4	0.1679 (6)	0.11593 (12)	−0.4500 (3)	0.0153 (5)
C5	0.2122 (6)	0.17501 (12)	−0.3950 (3)	0.0152 (5)
H5	0.1070	0.2096	−0.4460	0.018*
C6	0.4145 (6)	0.18255 (12)	−0.2634 (3)	0.0147 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.01488 (11)	0.02496 (12)	0.01033 (11)	−0.00102 (6)	−0.00139 (7)	−0.00023 (6)
Cl1	0.0267 (4)	0.0185 (3)	0.0174 (3)	0.0049 (3)	−0.0022 (3)	0.0043 (2)
Cl2	0.0266 (4)	0.0204 (3)	0.0107 (3)	−0.0007 (3)	−0.0035 (2)	−0.0005 (2)
Cl3	0.0293 (4)	0.0157 (3)	0.0158 (3)	−0.0012 (3)	−0.0005 (3)	−0.0029 (2)
C1	0.0126 (12)	0.0224 (13)	0.0084 (12)	−0.0012 (10)	0.0013 (9)	−0.0007 (10)
C2	0.0146 (12)	0.0173 (13)	0.0138 (12)	0.0021 (10)	0.0032 (9)	0.0049 (10)
C3	0.0211 (13)	0.0146 (12)	0.0148 (12)	−0.0014 (10)	0.0043 (10)	−0.0005 (10)
C4	0.0164 (13)	0.0204 (13)	0.0082 (12)	−0.0029 (10)	0.0002 (9)	−0.0013 (10)
C5	0.0169 (13)	0.0172 (13)	0.0113 (12)	0.0012 (10)	0.0020 (10)	0.0031 (10)
C6	0.0164 (13)	0.0159 (13)	0.0124 (12)	−0.0026 (10)	0.0039 (10)	−0.0025 (10)

Geometric parameters (Å, º)

I1—C1	2.085 (3)	C2—C3	1.387 (4)
Cl1—C2	1.732 (3)	C3—C4	1.387 (4)
Cl2—C4	1.737 (2)	C3—H3	0.9500
Cl3—C6	1.732 (3)	C4—C5	1.381 (4)
C1—C2	1.394 (4)	C5—C6	1.390 (3)
C1—C6	1.399 (4)	C5—H5	0.9500
C2—C1—C6	117.5 (2)	C5—C4—C3	121.7 (2)
C2—C1—I1	121.27 (18)	C5—C4—Cl2	119.5 (2)
C6—C1—I1	121.22 (18)	C3—C4—Cl2	118.8 (2)
C3—C2—C1	121.8 (2)	C4—C5—C6	118.4 (2)
C3—C2—Cl1	117.1 (2)	C4—C5—H5	120.8
C1—C2—Cl1	121.06 (19)	C6—C5—H5	120.8
C2—C3—C4	118.6 (2)	C5—C6—C1	121.9 (2)
C2—C3—H3	120.7	C5—C6—Cl3	117.1 (2)
C4—C3—H3	120.7	C1—C6—Cl3	120.92 (19)
C6—C1—C2—C3	−0.5 (4)	C3—C4—C5—C6	−0.2 (4)
I1—C1—C2—C3	179.05 (19)	Cl2—C4—C5—C6	−179.49 (19)
C6—C1—C2—Cl1	179.65 (18)	C4—C5—C6—C1	−0.3 (4)
I1—C1—C2—Cl1	−0.8 (3)	C4—C5—C6—Cl3	179.36 (18)
C1—C2—C3—C4	0.0 (4)	C2—C1—C6—C5	0.7 (4)
Cl1—C2—C3—C4	179.85 (19)	I1—C1—C6—C5	−178.90 (19)
C2—C3—C4—C5	0.4 (4)	C2—C1—C6—Cl3	−178.98 (19)
C2—C3—C4—Cl2	179.64 (19)	I1—C1—C6—Cl3	1.4 (3)