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Hexaiodobenzene

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Hexaiodobenzene
Names
Preferred IUPAC name Hexaiodobenzene
Other names Periodobenzene
Identifiers
CAS Number
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.009.246 Edit this at Wikidata
PubChem CID
UNII
CompTox Dashboard (EPA)
InChI
  • InChI=1S/C6I6/c7-1-2(8)4(10)6(12)5(11)3(1)9Key: QNMKKFHJKJJOMZ-UHFFFAOYSA-N
  • InChI=1/C6I6/c7-1-2(8)4(10)6(12)5(11)3(1)9Key: QNMKKFHJKJJOMZ-UHFFFAOYAO
SMILES
  • C1(=C(C(=C(C(=C1I)I)I)I)I)I
Properties
Chemical formula C6I6
Molar mass 833.493 g·mol
Appearance orange crystals
Density 4.60 g/cm
Melting point 430 °C (806 °F; 703 K)
Solubility in water insoluble
Structure
Crystal structure monoclinic
Space group P21/c, No. 14
Lattice constant a = 8.87 Å, b = 4.29 Å, c = 16.28 Åα = 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 , 100 kPa). Infobox references
Chemical compound

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 that are poorly soluble in all solvents. It adopts the expected structure with a central C6 ring.

Preparation

The compound was first prepared by iodination of benzoic acid in the presence of hot fuming sulfuric acid. 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.

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.

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. The structure is retained at high pressures up to 9.7 GPa.

References

  1. ^ Mattern, Daniell Lewis (1983). "Periodination of benzene with periodate/Iodide". The Journal of Organic Chemistry. 48 (24): 4772–4773. doi:10.1021/jo00172a063.
  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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