Chemistry:Hexaiodobenzene
| |
| Names | |
|---|---|
| Preferred IUPAC name
Hexaiodobenzene | |
| Other names
Periodobenzene
| |
| Identifiers | |
3D model (JSmol)
|
|
| ChemSpider | |
PubChem CID
|
|
| UNII | |
| |
| |
| Properties | |
| C6I6 | |
| Molar mass | 833.493 g·mol−1 |
| Appearance | orange 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°
| |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Hexaiodobenzene is a chemical compound 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]
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
- ↑ 1.0 1.1 1.2 1.3 Daniell Lewis Mattern: Periodination of Benzene with Periodate/Iodide, J. Org. Chem., 1983, 48 (24), pp. 4772–4773 (doi:10.1021/jo00172a063; PDF).
- ↑ 2.0 2.1 Steer, Rosemary J.; Watkins, S. F.; Woodward, P. (1970). "Crystal and molecular structure of hexaiodobenzene" (in en). Journal of the Chemical Society C: Organic (2): 403. doi:10.1039/j39700000403. ISSN 0022-4952. http://xlink.rsc.org/?DOI=j39700000403.
- ↑ 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).
- ↑ Erwin Rupp "Ueber die perhalogenirten Phtalsäuren und das Hexajodbenzol", Chem. Ber., 1896, Volume 29, pp. 1625–1634 (doi:10.1002/cber.18960290293).
- ↑ Mattern, Daniell Lewis (1983). "Periodination of benzene with periodate/iodide" (in en). The Journal of Organic Chemistry 48 (24): 4772–4773. doi:10.1021/jo00172a063. ISSN 0022-3263. https://pubs.acs.org/doi/abs/10.1021/jo00172a063.
- ↑ Nakayama, Atsuko; Fujihisa, Hiroshi; Aoki, Katsutoshi; Carlón, Raquel Pérez (2000-10-01). "Structural study of hexaiodobenzene up to 9.7 GPa" (in en). Physical Review B 62 (13): 8759–8765. doi:10.1103/PhysRevB.62.8759. ISSN 0163-1829. https://link.aps.org/doi/10.1103/PhysRevB.62.8759.
 |
