Potassium pyrosulfate

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Potassium pyrosulfate
Potassium pyrosulfate.png
Names
IUPAC name
dipotassium (sulfonatooxy)sulfonate
Other names
Potassium pyrosulphate; potassium disulfate
Identifiers
7790-62-7 YesY
ChemSpider 56432 N
Jmol 3D model Interactive image
PubChem 62681
Properties
K2O7S2
Molar mass 254.31 g·mol−1
Density 2.28 g/cm3
Melting point 325 °C (617 °F; 598 K)
soluble
Hazards
R-phrases R36 R38
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
Infobox references

Potassium pyrosulfate, or potassium disulfate, is an inorganic compound with the chemical formula K2S2O7.

Production[edit]

Potassium pyrosulfate is obtained by the thermal decomposition of other salts, most directly from potassium bisulfate:[1]

2 KHSO4 → K2S2O7 + H2O

Temperatures above 600°C further decompose potassium pyrosulfate to potassium sulfate and sulfur trioxide however:[2]

K2S2O7 → K2SO4 + SO3

Other salts, such as potassium trisulfate,[3] can also decompose into potassium pyrosulfate.

Chemical Structure[edit]

Potassium pyrosulfate contains the pyrosulfate anion which has a dichromate like structure. The geometry can be visualized as a tetrahedron with two corners sharing the SO4 anion's configuration and a centrally bridged oxygen atom.[4] A semi-structural formula for the pyrosulfate anion is O3SOSO32−. The oxidation state of sulfur in this compound is +6.

Uses[edit]

Potassium pyrosulfate is used in analytical chemistry; samples are fused with potassium pyrosulfate, (or a mixture of potassium pyrosulfate and potassium fluoride) to ensure complete dissolution prior to a quantitative analysis.[5][6]

The compound is also used as a catalyst in conjunction with vanadium(V) oxide in the industrial production of sulfur trioxide.[7]

See also[edit]

References[edit]

  1. ^ Washington Wiley, Harvey (1895). Principles and Practice of Agricultural Analysis: Fertilizers. Easton, PA.: Chemical Publishing Co. p. 218. Retrieved 31 December 2015. 
  2. ^ Iredelle Dillard Hinds, John (1908). Inorganic Chemistry: With the Elements of Physical and Theoretical Chemistry. New York: John Wiley & Sons. p. 547. Retrieved 31 December 2015. 
  3. ^ Brauer, Georg (1963). Handbook of Preparative Inorganic Chemistry Vol. 2, 2nd Ed. Newyork: Academic Press. p. 1716. ISBN 9780323161299. 
  4. ^ 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. 
  5. ^ 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. 
  6. ^ 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. 
  7. ^ Burkhardt, Donald (1965). "Sulfur trioxide production, US3362786A". Google Patents. Retrieved 31 December 2015.