Sodium Dithionite

Structurepotential (Eo' -0.66 V vs NHE at pH 7). Potassium
Raman spectroscopy and single-crystal X-rayferricyanide is usually used as an oxidizing chemical in
diffraction studies of sodium dithionite in the solidsuch experiments (Eo' ~ 436 mV at pH 7). In
state reveals that it exists in different forms. In oneaddition, sodium dithionite is often used in soil
anhydrous form, the dithionite ion has C2 geometry,chemistry experiments to determine the amount of
almost eclipsed with a 16 O-S-S-O torsional angle. Iniron that is not incorporated in primary silicate
the dihydrated form (Na2S2O4.2H2O), the dithioniteminerals. Hence, iron extracted by sodium dithionite is
anion has a shorter S-S bond length and a gauche 56also referred to as "free iron." The strong affinity of
O-S-S-O torsional angle.the dithionite ion for bi- and trivalent metal cations
Applications(M2+, M3+) allows it to enhance the solubility of iron,
Industryand therefore dithionite is a useful chelating agent.
This compound is a water-soluble salt, and can beWhen you heat the reaction, rainbow colors emerge
used as a reducing agent in aqueous solutions. It isdue to the high transition states of energy.
used as such in some industrial dying processes,Geosciences
where an otherwise water-insoluble dye can beSodium dithionite has been used in chemical Enhanced
reduced into a water-soluble alkali metal salt. TheOil Recovery to stabilize polyacrylamide polymers
reduction properties of sodium dithionite also eliminateagainst radical degradation in the presence of iron. It
excess dye, residual oxide, and unintended pigments,has also been used in environmental applications to
thereby improving overall colour quality. Reaction withpropagate a low Eh front in the subsurface in order
formaldehyde produces Rongalite, which is used as ato reduce pollutants such as chromium.
bleach, in, for instance, paper pulp, cotton, wool,See also
Leather, Chrome Tanning agent and kaolin clay.Dithionite
Na2S2O4 + 2 CH2O 2 HOCH2SO2 + 2 Na+References
Sodium dithionite can also be used for water^ Pratt, L. A. (1924). "The Manufacture of Sodium
treatment, gas purification, cleaning, and stripping. ItHyposulfite". Industrial & Engineering Chemistry
can also be used in industrial processes as a16: 676677. doi:10.1021/ie50175a006.  edit
sulfonating agent or a sodium ion source. In addition^ Weinrach, J. B. (1992). "A structural study of
to the textile industry, this compound is used insodium dithionite and its ephemeral dihydrate: A new
industries concerned with leather, foods, polymers,conformation for the dithionite ion". Journal of
photography, and many others. Its wide use isCrystallographic and Spectroscopic Research 22:
attributable to its low toxicity LD 50 at 5 g/kg, and291301. doi:10.1007/BF01199531.  edit
hence its wide range of applications.^ Herman Harry Szmant (1989). Organic building
Biological sciencesblocks of the chemical industry. John Wiley and Sons.
Sodium dithionite is often used in physiologyp. 113. ISBN 0471855456. 
experiments as a means of lowering solutions' redox^ S.G. Mayhew. Eur. J. Biochem.