1,3,5-Triiodo­benzene

Mol­ecules of the title compound, C₆H₃I₃, form stacks along the [100] direction. Neighbouring stacks are connected by weak inter­molecular C—H...I inter­actions.

Key indicators

• Single-crystal X-ray study
• T = 161 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.022
• wR factor = 0.049
• Data-to-parameter ratio = 36.9

checkCIF/PLATON results

No syntax errors found



Alert level C
STRVA01_ALERT_4_C           Flack test results are ambiguous.
           From the CIF: _refine_ls_abs_structure_Flack    0.390
           From the CIF: _refine_ls_abs_structure_Flack_su    0.040
PLAT033_ALERT_2_C Flack Parameter Value Deviates from Zero .......       0.39

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           32.40
           From the CIF: _reflns_number_total               3064
           Count of symmetry unique reflns         1895
           Completeness (_total/calc)            161.69%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1169
           Fraction of Friedel pairs measured     0.617
           Are heavy atom types Z>Si present        yes

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   1 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
   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: SMART (Siemens, 1995); cell refinement: SAINT (Siemens, 1995); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1996); software used to prepare material for publication: SHELXL97.

1,3,5-triiodobenzene

Crystal data

C6H3I3	F(000) = 792
Mr = 455.78	Dx = 3.387 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 249 reflections
a = 4.3287 (6) Å	θ = 3–23°
b = 14.224 (2) Å	µ = 10.41 mm^−1
c = 14.515 (2) Å	T = 161 K
V = 893.7 (2) Å^3	Rod, colourless
Z = 4	0.46 × 0.08 × 0.07 mm

Data collection

Siemens SMART 1K CCD area-detector diffractometer	3064 independent reflections
Radiation source: normal-focus sealed tube	2925 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.051
ω scans	θmax = 32.4°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 2000)	h = −6→6
Tmin = 0.176, Tmax = 0.483	k = −20→20
15783 measured reflections	l = −21→21

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.022	w = 1/[σ^2(Fo^2) + (0.02P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.049	(Δ/σ)max = 0.004
S = 1.07	Δρmax = 1.07 e Å^−3
3064 reflections	Δρmin = −0.58 e Å^−3
83 parameters	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.00248 (18)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), with 1223 Freidel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.39 (4)

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	0.24440 (5)	0.313277 (14)	0.404866 (14)	0.01943 (6)
I2	0.86272 (5)	0.530357 (14)	0.100282 (18)	0.02348 (6)
I3	0.93744 (5)	0.109258 (14)	0.107045 (16)	0.02226 (6)
C1	0.4977 (7)	0.3159 (2)	0.2814 (2)	0.0166 (6)
C2	0.5671 (8)	0.4023 (2)	0.2415 (2)	0.0183 (6)
H2	0.4919	0.4593	0.2672	0.022*
C3	0.7502 (8)	0.4024 (2)	0.1628 (2)	0.0180 (6)
C4	0.8563 (8)	0.3198 (2)	0.1230 (2)	0.0172 (6)
H4	0.9789	0.3211	0.0688	0.021*
C5	0.7788 (7)	0.2350 (2)	0.1647 (2)	0.0170 (6)
C6	0.5981 (8)	0.2319 (2)	0.2443 (2)	0.0174 (6)
H6	0.5458	0.1736	0.2723	0.021*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.02070 (10)	0.02406 (11)	0.01351 (10)	−0.00120 (8)	0.00139 (8)	−0.00118 (8)
I2	0.02692 (12)	0.01679 (10)	0.02673 (12)	−0.00289 (8)	0.00367 (9)	0.00462 (9)
I3	0.02590 (11)	0.01815 (10)	0.02274 (11)	0.00257 (8)	0.00218 (9)	−0.00398 (8)
C1	0.0145 (14)	0.0244 (16)	0.0109 (12)	−0.0016 (12)	−0.0006 (11)	0.0014 (12)
C2	0.0198 (15)	0.0161 (15)	0.0191 (15)	−0.0021 (12)	−0.0003 (12)	−0.0009 (11)
C3	0.0198 (14)	0.0155 (14)	0.0186 (15)	0.0007 (13)	−0.0005 (13)	0.0017 (11)
C4	0.0193 (14)	0.0175 (15)	0.0148 (14)	0.0005 (12)	0.0021 (11)	0.0008 (11)
C5	0.0163 (14)	0.0171 (14)	0.0175 (14)	0.0008 (12)	−0.0010 (11)	−0.0016 (11)
C6	0.0191 (15)	0.0160 (14)	0.0170 (15)	−0.0020 (11)	−0.0009 (12)	−0.0004 (11)

Geometric parameters (Å, º)

I1—C1	2.101 (3)	C2—H2	0.9500
I2—C3	2.091 (3)	C3—C4	1.388 (4)
I3—C5	2.090 (3)	C4—C5	1.390 (4)
C1—C6	1.381 (5)	C4—H4	0.9500
C1—C2	1.391 (4)	C5—C6	1.397 (5)
C2—C3	1.391 (5)	C6—H6	0.9500
C6—C1—C2	122.3 (3)	C3—C4—C5	118.3 (3)
C6—C1—I1	118.8 (2)	C3—C4—H4	120.8
C2—C1—I1	118.9 (2)	C5—C4—H4	120.8
C3—C2—C1	117.8 (3)	C4—C5—C6	121.5 (3)
C3—C2—H2	121.1	C4—C5—I3	119.3 (2)
C1—C2—H2	121.1	C6—C5—I3	119.2 (2)
C4—C3—C2	122.0 (3)	C1—C6—C5	118.2 (3)
C4—C3—I2	118.7 (2)	C1—C6—H6	120.9
C2—C3—I2	119.4 (2)	C5—C6—H6	120.9
C6—C1—C2—C3	−1.5 (5)	C3—C4—C5—C6	0.2 (5)
I1—C1—C2—C3	176.3 (2)	C3—C4—C5—I3	−179.6 (3)
C1—C2—C3—C4	1.5 (5)	C2—C1—C6—C5	0.8 (5)
C1—C2—C3—I2	−179.8 (3)	I1—C1—C6—C5	−177.0 (2)
C2—C3—C4—C5	−0.9 (5)	C4—C5—C6—C1	−0.1 (5)
I2—C3—C4—C5	−179.6 (2)	I3—C5—C6—C1	179.6 (2)