Potassium iodate

Names
IUPAC name Potassium iodate
Other names Iodic acid, potassium salt
Identifiers
CAS Number	7758-05-6 Y
3D model (JSmol)	Interactive image
ChemSpider	22856 Y
DrugBank	DB15923
ECHA InfoCard	100.028.938
EC Number	231-831-9
E number	E917 (glazing agents, ...)
PubChem CID	23665710
RTECS number	NN1350000
UNII	I139E44NHL Y
UN number	1479
CompTox Dashboard (EPA)	DTXSID5058480
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
SMILES [K+].[O-]I(=O)=O
Properties[1]
Chemical formula	KIO3
Molar mass	214.000 g·mol−1
Appearance	white monoclinic crystals
Density	3.89 g/cm3
Melting point	560 °C (1,040 °F; 833 K) (decomposes)
Solubility in water	9.16 g/100 mL
Solubility	Soluble in potassium iodide solution
log P	-1[2]
Magnetic susceptibility (χ)	−63.1×10−6 cm3/mol
Structure (Phase III (room temp.))[3]
Crystal structure	Triclinic
Space group	P1
Lattice constant	a = 7.744 Å, b = 7.718 Å, c = 7.733 Å α = 108.986°, β = 109.449°, γ = 109.209°
Lattice volume (V)	359.12 Å3
Formula units (Z)	4
Thermochemistry[1]
Heat capacity (C)	106.5 J⋅mol−1·K-1
Std molar entropy (S⦵298)	151.5 J⋅mol−1·K-1
Std enthalpy of formation (ΔfH⦵298)	−501.4 kJ⋅mol−1
Gibbs free energy (ΔfG⦵)	−418.4 kJ⋅mol−1
Hazards
GHS labelling:[4]
Pictograms
Signal word	Danger
Hazard statements	H272, H302, H319, H361
Precautionary statements	P201, P202, P210, P220, P264, P270, P280, P301+P312+P330, P305+P351+P338, P308+P313, P337+P313, P370+P378, P405, P501
NFPA 704 (fire diamond)	[2] 2 0 0 OX
Threshold limit value (TLV)	0.01 mg/m3 (as Iodine)[4] (TWA)
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). N verify (what is YN ?) Infobox references

Potassium iodate (KIO₃) is an ionic inorganic compound. It is a white salt that is soluble in water.^[5]

Preparation and properties

It can be prepared by reacting a potassium-containing base such as potassium hydroxide (KOH) with iodic acid (HIO₃), for example:^[5]

HIO₃ + KOH → KIO₃ + H₂O

It can also be prepared by adding iodine (I₂) to a hot, concentrated solution of potassium hydroxide:^[5]

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:^{[6][page needed]}

KI + KClO₃ → KIO₃ + KCl

The analogous reaction with potassium hypochlorite is also possible:^[7]

KI + 3 KOCl → 3 KCl + KIO₃

Applications

Potassium iodate is sometimes used for iodination of table salt to prevent iodine deficiency. In the US, iodized salt contains antioxidants, because atmospheric oxygen can oxidize wet iodide to iodine; other countries simply use potassium iodate instead.^[8] Salt mixed with ferrous fumarate and potassium iodate, "double fortified salt", are used to address both iron and iodine deficiencies.^[9] Potassium iodate is also used to provide iodine in some baby formulas.^[10]

Like potassium bromate, potassium iodate is occasionally used as a maturing agent in baking.^[11]

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.^[12]

Approved by the World Health Organization for radiation protection, KIO₃ is an alternative to potassium iodide, which has poor shelf life in hot and humid climates.^[13] The United Kingdom, Singapore, United Arab Emirates, and the U.S. states Idaho and Utah all maintain potassium iodate tablets towards this end.^{[citation needed]}

Following the September 11 attacks, the government of Ireland issued potassium iodate tablets to all households for a similar^{[clarification needed]} purpose.^[14]

Potassium iodate 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.^[15][16]

Safety

Potassium iodate is an oxidizing agent and as such it can form explosive mixtures when combined with organic compounds.^[5]

Conditions/substances to avoid^[when?] include: heat, shock, friction,^[17] combustible materials,^[5] reducing materials, aluminium,^[17] organic compounds,^[5] carbon, hydrogen peroxide and sulfides.^[17]

References