Potassium iodate

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Potassium iodate
Jodičnan draselný.JPG
IUPAC name
Potassium iodate
Other names
Iodic acid, potassium salt
3D model (JSmol)
ECHA InfoCard 100.028.938
EC Number 231-831-9
E number E917 (glazing agents, ...)
RTECS number NN1350000
Molar mass 214.001 g/mol
Appearance white crystalline powder
Odor odorless
Density 3.89 g/cm3
Melting point 560 °C (1,040 °F; 833 K) (decomposes)
4.74 g/100 mL (0 °C)
9.16 g/100 mL (25 °C)
32.3 g/100 mL (100 °C)
Solubility soluble in KI solution
insoluble in alcohol, liquid ammonia, nitric acid
−63.1·10−6 cm3/mol
R-phrases (outdated) R9, R22, R36, R37, R38
S-phrases (outdated) S35
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g., phosphorus Special hazard OX: Oxidizer. E.g., potassium perchlorateNFPA 704 four-colored diamond
Flash point Non-flammable
Related compounds
Other anions
Potassium chlorate
Potassium bromate
Other cations
Sodium iodate
Related compounds
Potassium iodide
Potassium periodate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Potassium iodate (KIO3) is a chemical compound. It is ionic, made up of K+ ions and IO3 ions in a 1:1 ratio.

Chemical properties[edit]

Potassium iodate is an oxidizing agent and as such it can cause fires if in contact with combustible materials or reducing agents. It can be prepared by reacting a potassium-containing base such as potassium hydroxide with iodic acid, for example:

HIO3 + KOH → KIO3 + H2O

It can also be prepared by adding iodine to a hot, concentrated solution of potassium hydroxide.

3 I2 + 6 KOH → KIO3 + 5 KI + 3 H2O

Or by fusing potassium iodide with potassium chlorate, bromate or perchlorate, the melt is extracted with water and potassium iodate is isolated from the solution by crystallization:[1]

KI + KClO3 → KIO3 + KCl

Conditions/substances to avoid include: heat, shock, friction, combustible materials, reducing materials, aluminium, organic compounds, carbon, hydrogen peroxide and sulfides.


Potassium iodate is sometimes used for iodination of table salt to prevent iodine deficiency. Because iodide can be oxidized to iodine by molecular oxygen under wet conditions, US companies add thiosulfates or other antioxidants to the potassium iodide. In other countries, potassium iodate is used as a source for dietary iodine. It is also an ingredient in some baby formula milk.

Like potassium bromate, potassium iodate is occasionally used as a maturing agent in baking.

Radiation protection[edit]

Potassium iodate may be used to protect against accumulation of radioactive iodine in the thyroid by saturating the body with a stable source of iodine prior to exposure.[2] Approved by the World Health Organization for radiation protection, potassium iodate (KIO3) is an alternative to potassium iodide (KI), which has poor shelf life in hot and humid climates.[3] The UK, Singapore, United Arab Emirates, and the U.S. states Idaho and Utah are known[by whom?] to stock potassium iodate in tablet form.[citation needed] The government of Ireland also, following the September 11 attacks, issued potassium iodate tablets to all households.[4][5] It is not approved by the U.S. Food and Drug Administration (FDA) for use as a thyroid blocker, and the FDA has taken action against US websites that promote this use.[6][7]

An unopened box of potassium iodate tablets, distributed to every household in Ireland in case of a terror attack on reprocessing plants such as Sellafield and nuclear power stations such as Wylfa in the United Kingdom. A scenario that upon later expert Irish examination in 2007, was found to not have justified their distribution.[8][5] The Irish government now upon realizing their error suggests that the tablets be disposed of with municipal waste.[5]
Recommended Dosage for Radiological Emergencies involving radioactive iodine[9]
Age KI in mg KIO3 in mg
Over 12 years old 130 170
3 – 12 years old 65 85
1 – 36 months old 32 42
< 1 month old 16 21