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The structure of the dithionate anion
A ball-and-stick model of the dithionate anion

The dithionate anion, S2O62−, is a sulfur oxoanion derived from dithionic acid, H2S2O6. Its chemical formula is sometimes written in a semistructural format, as [O3SSO3]2−.

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[1]. Aqueous solutions of dithionates are quite stable and can be boiled without decomposition [2].
The γ irradiation of crystalline dithionates produces SO3 radical ions[3]. The unpaired electron in the SO3 radical can be detected with electron paramagnetic resonance and barium dithionate has been proposed as the basis for a radiation dosimeter[4] The dithionate ion can act as a bidentate ligand [5].
The structure of the dithionate ion in the solid state is staggered in Na2S2O6.2H2O whereas in the anyhydrous potassium salt it is nearly eclipsed[1].


Compounds containing the dithionate ion include:


  1. 1.0 1.1 Template:Greenwood&Earnshaw
  2. Template:Cotton&Wilkinson6th
  3. Radiation Chemistry of Dithionates G.S. Murthy, R.L. Eager, and K.J. McCallum Can. J. Chem. 49(22),(1971), 3733
  4. 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
  5. Structures of Some Copper (II) Complexes Containing S2O62− Ion Ishii M. Bulletin of the Yamagata University 5, 1,(2001), 7

External links

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