The dithionate (or metabisulfate)

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

, , is a

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

oxoanion An oxyanion, or oxoanion, is an ion with the generic formula (where A represents a chemical element and O represents an oxygen atom). Oxyanions are formed by a large majority of the chemical elements. The formulae of simple oxyanions are determine ...

derived from

dithionic acid Dithionic acid, H2S2O6, is a chemical compound known only in solution. pp. 715-716 Salts Dithionic acid is diprotic and salts called dithionates are known. No acid salts (i.e.: one proton lost) have been discovered. All dithionates are readi ...

, H₂S₂O₆. Its

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

is sometimes written in a semistructural format, as ₃SSO₃sup>2−. It is the first member of the polythionates. The sulfur atoms of the dithionate ion are in the +5

oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...

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 The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ...

s and strong reducing agents reduce them to sulfites and

dithionite The dithionite is the oxyanion with the formula 2O4sup>2−. It is commonly encountered as the salt sodium dithionite. For historical reasons, it is sometimes called hydrosulfite, but it contains no hydrogen and is not a sulfite. The diani ...

s. Aqueous solutions of dithionates are quite stable and can be boiled without decomposition. The γ-irradiation of crystalline dithionates produces radical ions. The unpaired electron in the radical can be detected with

electron paramagnetic resonance Electron paramagnetic resonance (EPR) or electron spin resonance (ESR) spectroscopy is a method for studying materials that have unpaired electrons. The basic concepts of EPR are analogous to those of nuclear magnetic resonance (NMR), but the spi ...

and barium dithionate has been proposed as the basis for a radiation

dosimeter A radiation dosimeter is a device that measures dose uptake of external ionizing radiation. It is worn by the person being monitored when used as a personal dosimeter, and is a record of the radiation dose received. Modern electronic personal d ...

. The dithionate ion can act as a bidentate

ligand In coordination chemistry, a ligand is an ion or molecule ( functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's elec ...

.''Structures of Some Copper (II) Complexes Containing Ion'' Ishii M. ''Bulletin of the Yamagata University'' 5, 1,(2001), 7 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 In chemistry an eclipsed conformation is a conformation in which two substituents X and Y on adjacent atoms A, B are in closest proximity, implying that the torsion angle X–A–B–Y is 0°. Such a conformation can exist in any open chain, ...

Compounds

Compounds containing the dithionate ion include: *

sodium dithionate Sodium dithionate Na2S2O6 is an important compound for inorganic chemistry. It is also known under names disodium dithionate, sodium hyposulfate, and sodium metabisulfate. The sulfur can be considered to be in its +5 oxidation state. It should ...

, Na₂S₂O₆ *

potassium dithionite Potassium dithionite or potassium hydrosulfite is a potassium salt of dithionous acid. The compound has UN number UN 1929. As a dithionite, it is closely related to sodium dithionite, which is a commonly used reducing agent and bleaching agent ...

, K₂S₂O₆ * barium dithionate, BaS₂O₆

References

External links

{{commons category-inline, Dithionate ion Sulfur oxyanions