Diiodine hexaoxide

Diiodine hexaoxide
Names
Other names
iodine trioxide
Identifiers
3D model (JSmol)
  • InChI=1S/HIO4.IO2/c2-1(3,4)5;2-1-3/h(H,2,3,4,5);/q;+1/p-1
    Key: XOXXWUXXUGTNSE-UHFFFAOYSA-M
  • O=[I+]=O.O=[I-](=O)(=O)=O
Properties
I2O6
Molar mass 349.803 g·mol−1
Appearance yellow crust or crystals
Density 4.53 g/cm3[1]
Melting point 150 °C (302 °F; 423 K) (dec.)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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.

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. When heated above 150 °C, decomposition into diiodine pentoxide can be observed:

2 I2O6 → 2 I2O5 + O2

The compound is diamagnetic, which is attributed to the different oxidation numbers of the iodine atoms.[2] Structurally, the compound is iodyl periodate, an iodine(V,VII) oxide approximating 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]

See also

References

  1. ^ a b Kraft, Thorsten; Jansen, Martin (1995). "Synthesis and Crystal Structure of Diiodine(V/VII) Hexaoxide: An Intermediate between a Molecular and a Polymer Solid". Journal of the American Chemical Society. 117 (25): 6795–6796. doi:10.1021/ja00130a026.
  2. ^ a b c d Siebert, Hans; Weise, Manfred; Woerner, Ursula (1977). "Über das Jod(V, VII)-oxid J2O6". Zeitschrift für Anorganische und Allgemeine Chemie. 432: 136–140. doi:10.1002/zaac.19774320117.