Article · Wikipedia archive · Last revised Jun 27, 2026

Potassium iodate

Potassium iodate is an ionic inorganic compound. It is a white salt that is soluble in water.

Last revised
Jun 27, 2026
Read time
≈ 5 min
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1,054 w
Citations
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Source
Wikipedia ↗
Potassium iodate
source ↗
source ↗
Names
IUPAC name
Potassium iodate
Other names
Iodic acid, potassium salt
Identifiers
3D model (JSmol)
ChemSpider
DrugBank
ECHA InfoCard 100.028.938
EC Number
  • 231-831-9
E number E917 (glazing agents, ...)
RTECS number
  • NN1350000
UNII
UN number 1479
  • InChI=1S/HIO3.K/c2-1(3)4;/h(H,2,3,4);/q;+1/p-1 checkY
    Key: JLKDVMWYMMLWTI-UHFFFAOYSA-M checkY
  • InChI=1/HIO3.K/c2-1(3)4;/h(H,2,3,4);/q;+1/p-1
    Key: JLKDVMWYMMLWTI-REWHXWOFAL
  • [K+].[O-]I(=O)=O
Properties2
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)
9.16 g/100 mL
Solubility Soluble in potassium iodide solution
log P -11
−63.1×10−6 cm3/mol
Structure (Phase III (room temp.))3
Triclinic
P1
a = 7.744 Å, b = 7.718 Å, c = 7.733 Å
α = 108.986°, β = 109.449°, γ = 109.209°
359.12 Å3
4
Thermochemistry2
106.5 J⋅mol−1·K-1
151.5 J⋅mol−1·K-1
−501.4 kJ⋅mol−1
−418.4 kJ⋅mol−1
Hazards
GHS labelling:4
GHS03: OxidizingGHS08: Health hazardGHS07: Exclamation mark
Danger
H272, H302, H319, H361
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)
1
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazard OX: Oxidizer. E.g. potassium perchlorate
source ↗
2
0
0
OX
0.01 mg/m3 (as Iodine)4 (TWA)
Related compounds
Other anions
Other cations
 Sodium iodate
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

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

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

An unopened box of potassium iodate tablets distributed in the early 2000s to Irish households in case of a terror attack on British nuclear facilities. source ↗

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.

Following the September 11 attacks, the government of Ireland issued potassium iodate tablets to all households for a similar 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.1516

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 include: heat, shock, friction,17 combustible materials,5 reducing materials, aluminium,17 organic compounds,5 carbon, hydrogen peroxide and sulfides.17

References

References

  1. "SDS - Potassium iodate". www.fishersci.com. ThermoFisher Scientific. 18 December 2025. p. 3. Retrieved 14 May 2026.
  2. Haynes, William M., ed. (2016). CRC Handbook of Chemistry and Physics (97th ed.). Boca Raton, Florida: CRC Press. pp. 4–80, 4–130, 5–32. ISBN 9781498754293.
  3. Lucas, B. W. (15 December 1984). "Structure (neutron) of room-temperature phase III potassium iodate, KIO3". Acta Crystallographica Section C Crystal Structure Communications. 40 (12): 1989–1992. doi:10.1107/S0108270184010350.
  4. Sigma-Aldrich Co., Potassium iodate.
  5. Lyday, Phyllis A.; Kaiho Tatsuo (26 November 2015). "Iodine and Iodine Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. p. 9. doi:10.1002/14356007.a14_381.pub2. ISBN 978-3-527-30673-2.
  6. Patnaik, Pradyot (2003). Handbook of inorganic chemicals. New York, NY: McGraw-Hill. ISBN 0-07-049439-8.
  7. Andrews, Launcelot W. (July 1903). "Titrations with potassium iodide". Journal of the American Chemical Society. 25 (7). Easton, PA: 756. doi:10.1021/ja02009a012.
  8. Arroyave, Guillermo; Pineda, Oscar; Scrimshaw, Nevin S. (1956) [May 1955]. "The stability of potassium iodate in crude table salt". Bulletin of the World Health Organization. 14 (1): 183–185. PMC 2538103. PMID 13329845.
  9. Diosady, Levente L.; Mannar, M.G. Venkatesh; Krishnaswamy, Kiruba (2019). "Improving the lives of millions through new double fortification of salt technology". Maternal & Child Nutrition. 15 (Suppl 3) e12773. doi:10.1111/mcn.12773. PMC 6594086. PMID 31148400.
  10. James, Maia (2023-04-04). "Best Baby Formula Guide". Gimme the Good Stuff. Retrieved 2023-09-22.
  11. Carson, Lin (ed.). "Potassium iodate". BAKERpedia. Portland, OR. Retrieved 22 September 2023.
  12. Astbury, J; Horsley, S; Gent, N (1 December 1999). "Evaluation of a scheme for the pre-distribution of stable iodine (potassium iodate) to the civilian population residing within the immediate countermeasures zone of a nuclear submarine construction facility". Journal of Public Health. 21 (4): 412–414. doi:10.1093/pubmed/21.4.412. PMID 11469363.
  13. Pahuja, D.N.; Rajan, M.G.; Borkar, A.V.; Samuel, A.M. (Nov 2008). "Potassium iodate and its comparison to potassium iodide as a blocker of 131I uptake by the thyroid in rats". Health Physics. 65 (5): 545–9. doi:10.1097/00004032-199311000-00014. PMID 8225995.
  14. "Decision to Discontinue the Future Distribution of Iodine Tablets". Archived from the original on 2013-10-18. Retrieved 2013-05-22.
  15. "Potassium iodide vs potassium iodate. Which one works?".
  16. W. Charles Becoat (29 May 2003). "Potassium Iodate Warning Letter" (PDF). Food and Drug Administration.
  17. Regulatory Affairs (23 March 2023). "Safety Data Sheet" (Potassium iodate MSDS) (5 ed.). Fair Lawn, NJ: Thermo Fisher Scientific. Archived from the original on 22 September 2023. Retrieved 22 September 2023.