Disulfurous acid

Disulfurous acid
Names
IUPAC name
disulfurous acid[1]
Other names
pyrosulfurous acid
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
  • InChI=1S/H2O5S2/c1-6(2)7(3,4)5/h(H,1,2)(H,3,4,5) checkY
    Key: WBZKQQHYRPRKNJ-UHFFFAOYSA-N checkY
  • InChI=1S/H2O5S2/c1-6(2)7(3,4)5/h(H,1,2)(H,3,4,5)
  • O=S(=O)(O)S(=O)O
Properties
H2S2O5
Molar mass 146.13 g·mol−1
Conjugate base Disulfite
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Disulfurous acid, metabisulfurous acid or pyrosulfurous acid is an oxoacid of sulfur with the formula H2S2O5. Its structure is HO−S(=O)2−S(=O)−OH. The salts of disulfurous acid are called disulfites or metabisulfites. Disulfurous acid is, like sulfurous acid (H2SO3), a phantom acid, which does not exist in the free state.[2] In contrast to disulfate (S2O2−7), disulfite has two directly connected sulfur atoms. The oxidation state of the sulfur atom bonded to three oxygen atoms is +5 and its valence is 6, while that of the other sulfur is +3 and 4 respectively.

Disulfurous acid 1H NMR spectrum.
  1. ^ International Union of Pure and Applied Chemistry (2005). Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005). Cambridge (UK): RSCIUPAC. ISBN 0-85404-438-8. p. 130. Electronic version.
  2. ^ Holleman, Wiberg (2001). Inorganic Chemistry. Academic Press. pp. 537–540. ISBN 9780123526519.