Potassium periodate
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| Names | |
|---|---|
| IUPAC name
Potassium periodate
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| Other names
potassium metaperiodate
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.029.269 |
| EC Number |
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PubChem CID
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| UNII | |
| UN number | 3085 |
CompTox Dashboard (EPA)
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| Properties[2] | |
| KIO4 | |
| Molar mass | 229.999 g·mol−1 |
| Appearance | colorless tetrahedral crystals |
| Density | 3.618 g/cm3 |
| Melting point | 582 °C (1,080 °F; 855 K) |
| Boiling point | explodes |
| 0.51 g/100g | |
Solubility product (Ksp)
|
3.71×10−4 |
| Band gap | 2.433 eV[1] |
Refractive index (nD)
|
1.63[1] |
| Structure[1] | |
| tetragonal | |
| I41/a | |
| 4/m | |
a = 7.669 Å, b = 7.669 Å, c = 7.669 Å α = 135.102°, β = 135.102°, γ = 65.371°
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Lattice volume (V)
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221.443 Å3 |
Formula units (Z)
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2 |
| Thermochemistry[2] | |
Std molar
entropy (S⦵298) |
175.7 J⋅mol−1·K-1 |
Std enthalpy of
formation (ΔfH⦵298) |
−467.2 kJ⋅mol−1 |
Gibbs free energy (ΔfG⦵)
|
−361.4 kJ⋅mol−1 |
| Hazards | |
| GHS labelling:[3] | |
   
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| Danger | |
| H271, H314, H372, H400 | |
| P210, P220, P221, P260, P264, P270, P273, P280, P283, P301+P330+P331, P303+P361+P353, P304+P340+P310, P305+P351+P338+P310, P306+P360, P314, P363, P370+P378, P371+P380+P375, P391, P405, P501 | |
| NFPA 704 (fire diamond) | |
| Related compounds | |
Other anions
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Other cations
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Sodium periodate |
Related compounds
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Periodic acid |
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 periodate is an inorganic salt with the molecular formula KIO4. It is composed of a potassium cation and a periodate anion and may also be regarded as the potassium salt of periodic acid. Note that the pronunciation is per-iodate, not period-ate.
Unlike other common periodates, such as sodium periodate and periodic acid, it is only available in the meta-periodate form; the corresponding potassium ortho-periodate (K5IO6) has never been reported.
Preparation
[edit]Potassium periodate can be prepared by the oxidation of an aqueous solution of potassium iodate by chlorine and potassium hydroxide.[5]
- KIO3 + Cl2 + 2 KOH → KIO4 + 2 KCl + H2O
It can also be generated by the electrochemical oxidation of potassium iodate, however the low solubility of KIO3 makes this approach of limited use.
Chemical properties
[edit]Potassium periodate decomposes at 582 °C (1,080 °F) to form potassium iodate and oxygen.
The low solubility of KIO4 makes it useful for the determination of potassium[citation needed] and cerium.[6]
On heating (especially with manganese(IV) oxide as catalyst), it decomposes to form potassium iodate, releasing oxygen gas.[citation needed]
References
[edit]- ^ a b c "Potassium iodate(VII) - KIO4". legacy.materialsproject.org. Materials Project. doi:10.17188/1199594. 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, 5–33, 5–178. ISBN 9781498754293.
- ^ Sigma-Aldrich Co., Potassium periodate.
- ^ "SDS - Potassium periodate". www.fishersci.com. ThermoFisher Scientific. 19 December 2025. Retrieved 14 May 2026.
- ^ Schmeisser, M. Brauer, Georg (ed.). Handbook of preparative inorganic chemistry. Volume 1. Translated by Riley, Reed F. (2nd ed.). New York, N.Y.: Academic Press. p. 325. ISBN 978-0121266011.
- ^ Venugopalan, M.; George, K. J. (1956). "Determination of cerium by potassium periodate". Die Naturwissenschaften. 43 (15): 348–349. doi:10.1007/BF00755157.