Potassium sulfite is the inorganic compound with the formula K2SO3. It is the salt of potassium cation and sulfite anion. It is a white solid that is highly soluble in water. Potassium sulfite is used for preserving food and beverages.[2]

Production and reactions

Main article: Sulfite § Reactions
See also: Wellman–Lord process

Potassium sulfite is produced by the thermal decomposition of potassium metabisulfite at 190 °C:[3]

K2S2O5 → K2SO3 + SO2

Structure

The structure of solid K2SO3, as assessed by X-ray crystallography. The S-O distances are 1.515 Å, and the O-S-O angles are 105.2°[1]

References

  1. ^ a b Andersen, Leif; Strömberg, Dan; Nevala, H.; Pohjola, S.; Niinistö, Lauri; Volden, Hans V.; Weidlein, Johann; Zingaro, Ralph A. (1986). "The Structure of Potassium Sulfite". Acta Chemica Scandinavica. 40a: 479–480. doi:10.3891/acta.chem.scand.40a-0479.
  2. ^ "Potassium sulfite (225)". Codex Alimentarius. Food and Agriculture Organization of the United Nations.
  3. ^ Johnstone, H. F. (1946). "Sulfites and Pyrosulfites of the Alkali Metals". Inorganic Syntheses. Vol. 2. pp. 162–167. doi:10.1002/9780470132333.ch49. ISBN 9780470132333.