# Dithionate
> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Dithionate
> Markdown URL: https://mediated.wiki/source/Dithionate.md
> Source: https://en.wikipedia.org/wiki/Dithionate
> Source revision: 1242529208
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)
{{Short description|Ion}}
{{Distinguish|dithionite}}
{{Chembox
| ImageFileL1 = Dithionate-2D-dimensions.png
| ImageFileL1_Ref = {{chemboximage|correct|??}}
| ImageSizeL1 = 121
| ImageNameL1 = Skeletal formula of dithionate with assorted dimensions
| ImageFileR1 = Dithionate-3D-balls.png
| ImageFileR1_Ref = {{chemboximage|correct|??}}
| ImageSizeR1 = 121
| ImageNameR1 = Ball and stick model of dithionate
| IUPACName = Dithionate
| SystematicName = Bis(trioxidosulfate)(''S''—''S'')(2−)[{{Cite web|title = Dithionate(2−) (CHEBI:29209)|url = https://www.ebi.ac.uk/chebi/searchId.do?chebiId=29209|work = Chemical Entities of Biological Interest (ChEBI)|location = UK|publisher = European Bioinformatics Institute}}]
|Section1={{Chembox Identifiers
| CASNo = 14781-81-8
| PubChem = 3082075
| ChemSpiderID = 2339557
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChEBI = 29209
| SMILES = [O-][S+2]([O-])([O-])-[S+2]([O-])([O-])[O-]
| StdInChI = 1S/H2O6S2/c1-7(2,3)8(4,5)6/h(H,1,2,3)(H,4,5,6)/p-2
| StdInChIKey = RMGVZKRVHHSUIM-UHFFFAOYSA-L
}}
|Section2={{Chembox Properties
| Formula = {{chem|S|2|O|6|2−}}
| MolarMass = 160.126 g mol−1
| ConjugateAcid = [Dithionic acid](/source/Dithionic_acid)
| pKa = 0.5[{{cite book|title=Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution|editor-first=D. D.|editor-last=Perrin|edition=2nd|series=[IUPAC](/source/IUPAC) Chemical Data|issue=29|publisher=Pergamon|location=Oxford|year=1982|publication-date=1984|orig-date=1969|lccn=82-16524|isbn=0-08-029214-3|at=Entry 63}}]
}}
}}
The '''dithionate''' (or '''metabisulfate''') [anion](/source/anion), {{chem|S|2|O|6|2−}}, is a [sulfur](/source/sulfur) [oxoanion](/source/oxyanion)[{{RedBookRef|page=130}}] derived from [dithionic acid](/source/dithionic_acid), H2S2O6. Its [chemical formula](/source/chemical_formula) is sometimes written in a semistructural format, as [O3SSO3]2−. It is the first member of the [polythionates](/source/polythionates).
The sulfur atoms of the dithionate ion are in the +5 [oxidation state](/source/oxidation_state) due to the presence of the S–S bond. Generally, dithionates form stable compounds that are not readily oxidised or reduced. Strong oxidants oxidise them to [sulfate](/source/sulfate)s and strong reducing agents reduce them to [sulfite](/source/sulfite)s and [dithionite](/source/dithionite)s.[{{Greenwood&Earnshaw}}] Aqueous solutions of dithionates are quite stable and can be boiled without decomposition.[{{Cotton&Wilkinson6th}}]
The [γ-irradiation](/source/Gamma_radiation) of crystalline dithionates produces {{chem|SO|3|•−}} [radical](/source/radical_(chemistry)) ions.[''Radiation Chemistry of Dithionates'' G.S. Murthy, R.L. Eager, and K.J. McCallum Can. J. Chem. 49(22),(1971), 3733] The unpaired electron in the {{chem|SO|3|•−}} radical can be detected with [electron paramagnetic resonance](/source/electron_paramagnetic_resonance) and barium dithionate has been proposed as the basis for a radiation [dosimeter](/source/dosimetry).[''Barium dithionate as an EPR dosemeter'' Baran M.P., Bugay O.A., Kolesnik S. P., Maksimenko V. M., Teslenko V. V., Petrenko T. L. Desrosiers M. F. ''Radiation Protection Dosimetry'' 2006 '''120''', 202; {{doi|10.1093/rpd/nci531}}]
The dithionate ion can act as a bidentate [ligand](/source/ligand).[''Structures of Some Copper (II) Complexes Containing {{chem|S|2|O|6|2−}} Ion'' Ishii M. ''Bulletin of the Yamagata University'' '''5''', 1,(2001), 7]
The structure of the dithionate ion in the solid state is [staggered](/source/staggered_conformation) in Na2S2O6·2H2O, whereas in the anhydrous potassium salt it is nearly [eclipsed](/source/eclipsed_conformation).