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| Names | |
|---|---|
| Preferred IUPAC name
Hexaiodobenzene | |
| Other names
Periodobenzene | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.009.246 
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PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| 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° | |
| 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).
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Hexaiodobenzene is an aryl iodide and a six-substituted iodobenzene with the formula C6I6. Structurally, it is a derivativeofbenzene, 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]
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 iodideinsulfuric acid at 100 °C. This method instead produces 1,2,4,5-tetraiodobenzene if done at room temperature.[5]
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]
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]
