Potassium iodate

Chembox new
Name = Potassium iodate
OtherNames = iodic acid, potassium salt
Section1 = Chembox Identifiers
CASNo = 7758-05-6
Section2 = Chembox Properties
Formula = KIO₃
MolarMass = 214.00 g/mol
Appearance = white crystalline powder
Density = 3.89 g/cm³, solid
Solubility = 32g/100ml (100°C)
MeltingPt = 560°C
partial decomposition
BoilingPt =
Section7 = Chembox Hazards
EUClass = not listed
Section8 = Chembox Related
OtherAnions = potassium iodide
potassium periodate
potassium bromate
potassium chlorate
OtherCations = sodium iodate
silver iodate

Potassium iodate (KIO₃) is a chemical compound. It is sometimes used in radiation treatment, as it can replace radioactive iodine from the thyroid.

Chemical properties

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

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

Use

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

Potassium iodate may be used to protect against accumulation of radioactive iodine in the thyroid by saturating the body with an alternative source of iodine. Only potassium iodide has been tested and approved for this use by FDA and hence potassium iodate is not approved in the U.S. for this purpose, although it is used in some other countries such as the Republic of Ireland (see illustration).

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

References