Английская Википедия:Dithionic acid

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Dithionic acid, H₂S₂O₆, is a chemical compound known only in solution.

Salts

Шаблон:Main Dithionic acid is diprotic and salts called dithionates are known. No acid salts (i.e.: one proton lost) have been discovered. All dithionates are readily soluble in water. They are mild oxidizing and mild reducing agents. The shape of the dithionate ion is like ethane, but two SO₃ groups adopt an almost eclipsed conformation. The S—S bond length is about 2.15 Å; the S—O bonds are rather short with a bond length of 1.43 Å.

Synthesis

Dithionates can be made by oxidizing a sulfite (from the +4 to the +5 oxidation state), but on a larger scale they are made by oxidizing a cooled aqueous solution of sulfur dioxide with manganese dioxide:

2 MnO₂ + 3 SO₂ → MnS₂O₆ + MnSO₄

The manganese dithionate solution formed can then be converted to dithionate salts of other metals by metathesis reactions:

Ba²⁺(Шаблон:Abbr) + MnS₂O₆(Шаблон:Abbr) + MnSO₄(Шаблон:Abbr) → BaSO₄(Шаблон:Abbr)↓ + BaS₂O₆·2H₂O(Шаблон:Abbr)

Concentrated solutions of dithionic acid can subsequently be obtained treating a barium dithionate solution with sulfuric acid:

BaS₂O₆(Шаблон:Abbr) + H₂SO₄(Шаблон:Abbr) → H₂S₂O₆(Шаблон:Abbr) + BaSO₄(Шаблон:Abbr)↓

See also

• Hypophosphoric acid, the phosphorus equivalent.

References

Шаблон:Reflist www.chemindustry.com/chemicals/1022920.html - CASNo reference