Dithionate

{{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−)<ref>{{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}}</ref> |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 | pKa = 0.5<ref name=P82db>{{cite book|title=Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution|editor-first=D.&nbsp;D.|editor-last=Perrin|edition=2nd|series=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}}</ref> }} }}

The '''dithionate''' (or '''metabisulfate''') anion, {{chem|S|2|O|6|2−}}, is a sulfur oxoanion<ref>{{RedBookRef|page=130}}</ref> derived from dithionic acid, H₂S₂O₆. Its chemical formula is sometimes written in a semistructural format, as [O₃SSO₃]²⁻. It is the first member of the polythionates.

The sulfur atoms of the dithionate ion are in the +5 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 sulfates and strong reducing agents reduce them to sulfites and dithionites.<ref name = greenwood>{{Greenwood&Earnshaw}}</ref> Aqueous solutions of dithionates are quite stable and can be boiled without decomposition.<ref>{{Cotton&Wilkinson6th}}</ref>

The γ-irradiation of crystalline dithionates produces {{chem|SO|3|•−}} radical ions.<ref>''Radiation Chemistry of Dithionates'' G.S. Murthy, R.L. Eager, and K.J. McCallum Can. J. Chem. 49(22),(1971), 3733</ref> The unpaired electron in the {{chem|SO|3|•−}} radical can be detected with electron paramagnetic resonance and barium dithionate has been proposed as the basis for a radiation dosimeter.<ref>''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}}</ref>

The dithionate ion can act as a bidentate ligand.<ref>''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</ref>

The structure of the dithionate ion in the solid state is staggered in Na₂S₂O₆·2H₂O, whereas in the anhydrous potassium salt it is nearly eclipsed.<ref name = greenwood />

==Compounds== Compounds containing the dithionate ion include:

* sodium dithionate, Na₂S₂O₆ * potassium dithionate, K₂S₂O₆ * barium dithionate, BaS₂O₆

==References== {{Reflist}}

==External links== {{commons category-inline|Dithionate ion}}

Category:Dithionates Category:Sulfur oxyanions