Iodine pentoxide

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Iodine pentoxide
IUPAC name diiodine heptoxide
Other names iodine(V) oxide; iodic anhydride
Identifiers
CAS number [12029-98-0]
Properties
Molecular formula I2O5
Molar mass 333.81 g/mol
Appearance white crystalline solid[1]
Density 4.980 g cm−3[1]
Melting point

? °C

Boiling point

? °C

Hazards
Main hazards oxidizer
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Iodine pentoxide is the chemical compound with the formula I2O5. This iodine oxide is the anhydride of iodic acid. It is produced by dehydrating iodic acid at 200 °C in a stream of dry air[1]:

2HIO3 → I2O5 + H2O

[edit] Structure

I2O5 is bent with an I-O-I angle of 139.2°, but the molecule has no mirror plane so its symmetry is not C2v. The terminal I-O distances are around 1.80 Å and the bridging I-O distances are around 1.95 Å[2].

[edit] Reactions

Iodine pentoxide easily oxidises carbon monoxide to carbon dioxide at room temperature:

5CO + I2O5 → I2 + 5CO2

This reaction can be used to analyse the concentration of CO in a gaseous sample.

I2O5 forms iodyl salts, [IO2+], with SO3 and S2O6F2, but iodosyl salts, [IO+], with concentrated sulfuric acid.

[edit] References

  1. ^ a b c Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements, 2nd Edition, Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.  pp. 851-852
  2. ^ K. Selte and A. Kjekshus (1970). "Iodine oxides: part III, The crystal structure of I2O5". Acta Chemica Scandinavica 24: 1912–1914. 
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