Dithionous acid

Dithionous acid
Names
	IUPAC name Dithionous acid
	Other names Hydrosulfurous acid; Hyposulfurous acid
Identifiers
CAS Number	15959-26-9 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:29253 ;
ChemSpider	22898 ;
PubChem CID	24490;
CompTox Dashboard (EPA)	DTXSID70274771 ;
	InChI InChI=1S/H2O4S2/c1-5(2)6(3)4/h(H,1,2)(H,3,4) Key: GRWZHXKQBITJKP-UHFFFAOYSA-N ; InChI=1/H2O4S2/c1-5(2)6(3)4/h(H,1,2)(H,3,4) Key: GRWZHXKQBITJKP-UHFFFAOYAX;
	SMILES O=S(O)S(=O)O;
Properties
Chemical formula	H2S2O4
Molar mass	130.144 g/mol
Acidity (pKa)	0.35, 2.45
Conjugate base	Dithionite
Related compounds
Related compounds	Oxalic acid; Sodium dithionite; Potassium dithionite
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Dithionous acid is a sulfur oxoacid with the chemical formula H₂S₂O₄. It has not been observed experimentally.^[2] It is the conjugate base of the dithionite dianion, S₂O₄^2-. Dithionite is a well-known reducing agent.

^ Catherine E. Housecroft; Alan G. Sharpe (2008). "Chapter 16: The group 16 elements". Inorganic Chemistry, 3rd Edition. Pearson. p. 520. ISBN 978-0-13-175553-6.
^ Drozdova, Yana; Steudel, Ralf; Hertwig, Roland H.; Koch, Wolfram; Steiger, Thomas (1998). "Structures and Energies of Various Isomers of Dithionous Acid, H2S2O4, and of Its Anion HS2O4- 1". The Journal of Physical Chemistry A. 102 (6): 990–996. Bibcode:1998JPCA..102..990D. doi:10.1021/jp972658d.

[InorgChem-1] Catherine E. Housecroft; Alan G. Sharpe (2008). "Chapter 16: The group 16 elements". Inorganic Chemistry, 3rd Edition. Pearson. p. 520. ISBN 978-0-13-175553-6.

[drozdova-2] Drozdova, Yana; Steudel, Ralf; Hertwig, Roland H.; Koch, Wolfram; Steiger, Thomas (1998). "Structures and Energies of Various Isomers of Dithionous Acid, H2S2O4, and of Its Anion HS2O4- 1". The Journal of Physical Chemistry A. 102 (6): 990–996. Bibcode:1998JPCA..102..990D. doi:10.1021/jp972658d.

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