Hexaiodobenzene

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Hexaiodobenzene
Hexaiodobenzene.svg
Names
Preferred IUPAC name
Hexaiodobenzene
Other names
Periodobenzene
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.009.246 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/C6I6/c7-1-2(8)4(10)6(12)5(11)3(1)9
    Key: QNMKKFHJKJJOMZ-UHFFFAOYSA-N
  • InChI=1/C6I6/c7-1-2(8)4(10)6(12)5(11)3(1)9
    Key: QNMKKFHJKJJOMZ-UHFFFAOYAO
  • C1(=C(C(=C(C(=C1I)I)I)I)I)I
Properties
C6I6
Molar mass 833.493 g·mol−1
Appearanceorange crystals [1]
Density 4.60 g/cm3
Melting point 430 °C (806 °F; 703 K) [1]
insoluble
Structure [2]
monoclinic
P21/c, No. 14
a = 8.87 Å, b = 4.29 Å, c = 16.28 Å
α = 90°, β = 93°, γ = 90°
Related compounds
Related compounds
 Hexafluorobenzene
Hexachlorobenzene
Hexabromobenzene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Hexaiodobenzene is an aryl iodide and a six-substituted iodobenzene with the formula C6I6. Structurally, it is a derivative of benzene, in which all hydrogen atoms are replaced by iodine atoms. It forms orange crystals [1] that are poorly soluble in all solvents. It adopts the expected structure with a central C6 ring. [3]

Contents

Preparation

The compound was first prepared by iodination of benzoic acid in the presence of hot fuming sulfuric acid. [4] Another method of synthesis is the reaction between benzene with periodic acid and potassium iodide in sulfuric acid at 100 °C. This method instead produces 1,2,4,5-tetraiodobenzene if done at room temperature. [5]

Properties

Physical properties

Hexaiodobenzene forms orange needles that are practically insoluble in water, but sparingly soluble in N-methyl-2-pyrrolidone and dimethyl sulfoxide. It melts at 430 °C, but also already begins to show some decomposition at 370 °C, forming I2. [1]

Crystallographic properties

The crystals are monoclinic and pseudohexagonal, with centrosymmetric C6I6 units. The carbon atoms lie in a plane with C–C distances about 141 pm, while the nearby iodine atoms show very small displacements (about 4 pm) above and below the ring. The shortest intermolecular distance, 376 pm, is notably short compared to twice the Van der Waals radius, which is 430 pm. [2] The structure is retained at high pressures up to 9.7 GPa. [6]

References

  1. 1 2 3 4 Mattern, Daniell Lewis (1983). "Periodination of benzene with periodate/Iodide". The Journal of Organic Chemistry. 48 (24): 4772–4773. doi:10.1021/jo00172a063.
  2. 1 2 Steer, Rosemary J.; Watkins, S. F.; Woodward, P. (1970). "Crystal and molecular structure of hexaiodobenzene" . Journal of the Chemical Society C: Organic (2): 403. doi:10.1039/j39700000403. ISSN   0022-4952.
  3. ↑ Ghosh, Sandip; Reddy, C. Malla; Desiraju, Gautam R. "Hexaiodobenzene: a redetermination at 100 K", Acta Crystallographica, Section E: Structure Reports Online, 2007, 63(2), o910–o911 ( doi : 10.1107/S1600536807002279).
  4. ↑ Erwin Rupp "Ueber die perhalogenirten Phtalsäuren und das Hexajodbenzol", Chem. Ber., 1896, Volume 29, pp. 1625–1634 ( doi : 10.1002/cber.18960290293).
  5. ↑ Mattern, Daniell Lewis (1983). "Periodination of benzene with periodate/iodide" . The Journal of Organic Chemistry. 48 (24): 4772–4773. doi:10.1021/jo00172a063. ISSN   0022-3263.
  6. ↑ Nakayama, Atsuko; Fujihisa, Hiroshi; Aoki, Katsutoshi; Carlón, Raquel Pérez (2000-10-01). "Structural study of hexaiodobenzene up to 9.7 GPa" . Physical Review B. 62 (13): 8759–8765. doi:10.1103/PhysRevB.62.8759. ISSN   0163-1829.
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