Anhydro-iodic acid

Anhydro-iodic acid
IUPAC name	iodic acid — diiodine pentaoxide (1/1)
Identifiers
InChI	InChI=1/I2O5.HIO3/c3-1(4)7-2(5)6;2-1(3)4/h;(H,2,3,4)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Anhydro-iodic acid, HI₃O₈, is an adduct of iodic acid and iodine pentoxide, i.e. HIO₃·I₂O₅. It is formed by the partial dehydration of iodic acid at about 100 °C, or by absorption of water by iodine pentoxide.{#tag:ref|Commercial "I₂O₅" is said to be essentially anhydro-iodic acid.|group=Note}} It can be dehydrated to I₂O₅ by heating in dry air to about 200 °C.

Notes and references

Further reading

• Feikema, Y. D.; Vos, Aafje The crystal structures of two oxy-acids of iodine. II. An X-ray diffraction study of anhydro-iodic acid, HI₃O₈. Acta Crystallogr. 1966, 20 (6), 769–77. DOI: 10.1107/S0365110X6600183X.
• Ståhl, Kenny; Svensson, Christer; Szafranski, Marek A Combined Neutron Powder and X-Ray Single Crystal Diffraction Study of Anhydro-Iodic Acid, DIO₃·I₂O₅, at 293 K. J. Solid State Chem. 1993, 102 (2), 408–13. DOI: 10.1006/jssc.1993.1052.