Potassium iodate

Potassium iodate
IUPAC name Potassium iodate
Other names Iodic acid, potassium salt
Identifiers
CAS number	7758-05-6 Y
PubChem	24448
ChemSpider	22856 Y
UNII	I139E44NHL Y
Jmol-3D images	{{#if:[K+].[O-]I(=O)=O|Image 1
SMILES [K+].[O-]I(=O)=O
InChI InChI=1S/HIO3.K/c2-1(3)4;/h(H,2,3,4);/q;+1/p-1 Y Key: JLKDVMWYMMLWTI-UHFFFAOYSA-M Y InChI=1/HIO3.K/c2-1(3)4;/h(H,2,3,4);/q;+1/p-1 Key: JLKDVMWYMMLWTI-REWHXWOFAL
Properties
Molecular formula	KIO3
Molar mass	214.001 g/mol
Appearance	white crystalline powder
Odor	odorless
Density	3.89 g/cm3
Melting point	560 °C decomp.
Solubility in water	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
Hazards
EU Index	Oxidant [O]
R-phrases	R9, R22, R36, R37, R38
S-phrases	S35
NFPA 704	0 2 1
Flash point	Non-flammable
Related compounds
Other anions	Potassium chlorate Potassium bromate
Other cations	Sodium iodate
Related compounds	Potassium iodide Potassium periodate
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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

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:^[4]

KI + KClO₃ → KIO₃ + KCl

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

Applications

Potassium iodate is sometimes used for iodination of table salt to prevent iodine deficiency. Because iodide can be oxidized by molecular oxygen to iodine 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

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.^[5] 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.^[6] The UK, Singapore, United Arab Emirates, and the US states Idaho and Utah are known 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.^[7][8] 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.^[9][10]

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.^[1][2] The Irish government now upon realizing their error suggests that the tablets be disposed of with municipal waste.^[3]

References