Diiodine hexaoxide
Chemical compound
From Wikipedia, the free encyclopedia
Diiodine hexaoxide, is a chemical compound of oxygen and iodine with the chemical formula I2O6. It belongs to the class of iodine oxides, and is a mixed oxide, consisting of iodine(V) and iodine(VII) oxidation states.
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| Names | |
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| Other names
iodine trioxide, diiodine(V,VII) oxide | |
| Identifiers | |
3D model (JSmol) |
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| Properties | |
| I2O6 | |
| Molar mass | 349.803 g·mol−1 |
| Appearance | yellow crust or crystals |
| Density | 4.53 g/cm3[1] |
| Melting point | 179 °C (354 °F; 452 K) (dec.) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Synthesis
Reaction of periodic acid with iodic acid in sulfuric acid:[2]
- HIO3 + H5IO6 → I2O6 + 3H2O
The thermal decomposition of meta-periodic acid in vacuum also leads to the formation of diiodine hexoxide.[2]
Chemical properties
Below 100 °C, diiodine hexaoxide can be stored stably in the absence of moisture. When dissolved in water, an exothermic reaction to form iodine and periodic acid takes place.[citation needed] When heated above 179 °C, decomposition into diiodine pentoxide can be observed, with the reaction going to completion at 197 °C:[3]
- 2 I2O6 → 2 I2O5 + O2
Structurally, the compound is a polymeric iodine(V,VII) oxide consisting of repeating I4O12, units[1] contradicting previous sources describing it as "iodyl periodate" (IO2+IO4-).[2] As a solid, the compound crystallizes in the space group P1 (space group no. 2) with the lattice constants a = 500.6 pm, b = 674.1 pm, c = 679.5 pm, α = 97.1°, β = 96.43°, γ = 105.36° with one formula unit per unit cell.[1]
Uses
Diiodine hexaoxide has been investigated for potential use as a neutralizer for chemical and biological agents in combination with aluminium powder.[3]