Potassium iodate
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| Names | |
|---|---|
| IUPAC name
Potassium iodate
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| Other names
Iodic acid, potassium salt
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| DrugBank | |
| ECHA InfoCard | 100.028.938 |
| EC Number |
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| E number | E917 (glazing agents, ...) |
PubChem CID
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| RTECS number |
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| UNII | |
| UN number | 1479 |
CompTox Dashboard (EPA)
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| Properties[2] | |
| 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 | -1[1] |
| −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°
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Lattice volume (V)
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359.12 Å3 |
Formula units (Z)
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4 |
| Thermochemistry[2] | |
Heat capacity (C)
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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⦵)
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−418.4 kJ⋅mol−1 |
| Hazards | |
| GHS labelling:[4] | |
  
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| 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) | |
Threshold limit value (TLV)
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0.01 mg/m3 (as Iodine)[4] (TWA) |
| Related compounds | |
Other anions
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Other cations
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Sodium iodate |
Related compounds
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Potassium iodate (KIO3) is an ionic inorganic compound. It is a white salt that is soluble in water.[5]
Preparation and properties
[edit]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
[edit]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
[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.[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
[edit]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
[edit]- ^ a b "SDS - Potassium iodate". www.fishersci.com. ThermoFisher Scientific. 18 December 2025. p. 3. Retrieved 14 May 2026.
- ^ a b 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.
- ^ 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.
- ^ a b Sigma-Aldrich Co., Potassium iodate.
- ^ a b c d e f 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.
- ^ Patnaik, Pradyot (2003). Handbook of inorganic chemicals. New York, NY: McGraw-Hill. ISBN 0-07-049439-8.
- ^ Andrews, Launcelot W. (July 1903). "Titrations with potassium iodide". Journal of the American Chemical Society. 25 (7). Easton, PA: 756. doi:10.1021/ja02009a012.
- ^ 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.
- ^ 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.
- ^ James, Maia (2023-04-04). "Best Baby Formula Guide". Gimme the Good Stuff. Retrieved 2023-09-22.
- ^ Carson, Lin (ed.). "Potassium iodate". BAKERpedia. Portland, OR. Retrieved 22 September 2023.
- ^ 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.
- ^ 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.
- ^ "Decision to Discontinue the Future Distribution of Iodine Tablets". Archived from the original on 2013-10-18. Retrieved 2013-05-22.
- ^ "Potassium iodide vs potassium iodate. Which one works?".
- ^ W. Charles Becoat (29 May 2003). "Potassium Iodate Warning Letter" (PDF). Food and Drug Administration.
- ^ a b c 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.