Potassium iodate
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
  • 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
Properties
KIO3
Molar mass 214.001 g/mol
Appearance white crystalline powder
Odor odorless
Density 3.89 g/cm3
Melting point 560 °C (1,040 °F; 833 K) (decomposes)
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
−63.1·10−6 cm3/mol
Hazards
GHS labelling:
GHS03: Oxidizing GHS05: Corrosive GHS07: Exclamation mark
H272, H302, H318
P210, P280, P301+P312+P330, P305+P351+P338+P310
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond
2
0
2
OX
Flash point Non-flammable
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 checkY☒N ?)
Infobox references

Potassium iodate (KIO3) is an ionic chemical compound consisting of K+ ions and IO3− ions in a 1:1 ratio.

Preparation and 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:[1]

HIO3 + KOH → KIO3 + H2O

It can also be prepared by adding iodine to a hot, concentrated solution of potassium hydroxide:[1]

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:[2]

KI + KClO3 → KIO3 + KCl

The analogous reaction with potassium hypochlorite is also possible:[3]

KI + 3KOCl → 3KCl + KIO3

Conditions/substances to avoid include: heat, shock, friction,[4] combustible materials,[1] reducing materials, aluminium,[4] organic compounds,[1] carbon, hydrogen peroxide and sulfides.[4]

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.[5] Potassium iodate is also an ingredient in some baby formula.[6]

Like potassium bromate, potassium iodate is occasionally used as a maturing agent in baking.[7]

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.

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.[8] 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.[9] The UK, 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.[10]

Recommended Dosage for Radiological Emergencies involving radioactive iodine[11]
Age KI in mg KIO3 in mg
Over 12 years old 130 170
3 – 12 years old 65 85
1 – 36 months old 32 42
< 1 month old 16 21

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.[12][13]

References

  1. 1 2 3 4 Lyday, Phyllis A.; Kaiho Tatsuo (26 November 2015). "Iodine and Iodine Compounds". In Ley, Claudia (ed.). Ullmann's Encyclopedia of Industrial Chemistry (7th ed.). Weinheim: Wiley-VCH. p. 9. doi:10.1002/14356007.a14_381.pub2. ISBN 9783527306732.
  2. ↑ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  3. ↑ Andrews, Launcelot W. (July 1903). "Titrations with potassium iodide". Journal of the American Chemical Society. Easton, PA: US Postal Service. 25 (7): 756. doi:10.1021/ja02009a012 – via HathiTrust.
  4. 1 2 3 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.
  5. ↑ 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.
  6. ↑ James, Maia (2023-04-04). "Best Baby Formula Guide". Gimme the Good Stuff. Retrieved 2023-09-22.
  7. ↑ Carson, Lin (ed.). "Potassium iodate". BAKERpedia. Portland, OR. Retrieved 22 September 2023.
  8. ↑ Astbury, John; Horsley, Stephen; Gent, Nick (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): 2008–10, doi:10.1093/pubmed/21.4.412, PMID 11469363, archived from the original on 2008-09-05
  9. ↑ 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
  10. ↑ "Decision to Discontinue the Future Distribution of Iodine Tablets". Archived from the original on 2013-10-18. Retrieved 2013-05-22.
  11. ↑ Guidelines for Iodine Prophylaxis following Nuclear Accidents (PDF), Geneva: World Health Organization, 1999
  12. ↑ "Potassium iodide vs potassium iodate. Which one works?".
  13. ↑ W. Charles Becoat (29 May 2003). "Potassium Iodate Warning Letter" (PDF). Food and Drug Administration.
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