Potassium pyrosulfate

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Potassium pyrosulfate
Potassium pyrosulfate.png
CAS number 7790-62-7 YesY
PubChem 62681
Jmol-3D images Image 1
Molecular formula K2O7S2
Molar mass 254.32 g mol−1
Density 2.28 g/cm3
Melting point 325 °C (617 °F; 598 K)
Solubility in water soluble
R-phrases R36 R38
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

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 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.[2][3]

It is also used as a catalyst in conjunction with vanadium(V) oxide, for example.[4]

See also[edit]


  1. ^ Ståhl, K.; Balic-Zunic, T.; da Silva, F.; Eriksen, K. M.; Berg, R. W.; Fehrmann, R. (2005). "The crystal structure determination and refinements of K2S2O7, KNaS2O7 and Na2S2O7 from X-ray powder and single crystal diffraction data". Journal of Solid State Chemistry 178 (5): 1697–1704. Bibcode:2005JSSCh.178.1697S. doi:10.1016/j.jssc.2005.03.022. 
  2. ^ Trostbl, L. J.; Wynne, D. J. (1940). "Determination of quartz (free silica) in refractory clays". Journal of the American Ceramic Society 23 (1): 18–22. doi:10.1111/j.1151-2916.1940.tb14187.x. 
  3. ^ Sill, C. W. (1980). "Determination of gross alpha, plutonium, neptunium, and/or uranium by gross alpha counting on barium sulphate". Analytical Chemistry 52 (9): 1452–1459. doi:10.1021/ac50059a018. 
  4. ^ Sulfur trioxide production BurkhardtD.B. US patent no. 3362786 issued Jan 1968,