Potassium pyrosulfate: Difference between revisions
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| K = 2 | O = 7 | S = 2 |
| K = 2 | O = 7 | S = 2 |
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| Density= 2. |
| Density= 2.25g/cm<sup>3</sup> |
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| MeltingPtC= 325 |
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Revision as of 23:46, 25 February 2009
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| Names | |
|---|---|
| Other names
Potassium pyrosulphate; potassium disulfate
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| Identifiers | |
3D model (JSmol)
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| ECHA InfoCard | 100.029.288 |
PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |
| K2O7S2 | |
| Molar mass | 254.31 g·mol−1 |
| Density | 2.25g/cm3 |
| Melting point | 325 °C (617 °F; 598 K) |
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 pyrosulfate (potassium disulfate) is a chemical compound, K2S2O7. It contains the pyrosulfate anion S2O72− which has a dichromate like structure and can be visualised as two corner sharing SO4 tetrahedra, with a bridging oxygen atom.[1] A semi-structural formula for pyrosulfate ion is O3SOSO32−. In this compound sulfur has an oxidation state of +6.
Potassium pyrosulfate is most commonly found as a preservative in consumer foods. The European Union approved food additive E-code for potassium disulfate is E224. As a food additive or preservative K2S2O7 is also known as Potassium metabisulphite. [2]
Potassium pyrosulfate is used in analytical chemistry; samples are fused with potassium pyrosulfate,(or a mixture of potassium pyrosulfate and potassium fluoride, KF) to ensure complete dissolution prior to a quantitative analysis.[3][4]
It is also used as a catalyst in conjunction with vanadium(V) oxide, for example.[5]
See also
References
- ^ The crystal structure determination and refinements of K2S2O7, KNaS2O7 and Na2S2O7 from X-ray powder and single crystal diffraction data Ståhl K , Balic-Zunic T, da Silva F, Eriksen K M , Berg R W Fehrmann R Journal of Solid State Chemistry 178, 1697-1704, (2005) doi:10.1016/j.jssc.2005.03.022
- ^ E-numbers database, Wageningen University food safety information -site, Food Technology Department http://www.food-info.net/uk/e/e224.htm
- ^ Determination of quartz (free silica) in refractory clays Trostbl L.J., Wynne D.J. Journal of the American Ceramic Society 23 1 18, (1940) doi:10.1111/j.1151-2916.1940.tb14187.x
- ^ Determination of gross alpha, plutonium, neptunium, and/or uranium by gross alpha counting on barium sulphate C. W. Sill Analytical Chemistry, (1980) 52, 1452
- ^ Sulfur trioxide production BurkhardtD.B. US patent no. 3362786 issued Jan 1968,