Ferricyanide

Ferricyanide
IUPAC name

iron(3+) hexacyanide
Systematic name

hexacyanidoferrate(III)
Other names

ferric hexacyanide; hexacyanidoferrate(3-); hexacyanoferrate(III)
Identifiers
PubChem 439210
Jmol-3D images Image 1
 Y (verify) (what is: Y/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Ferricyanide is the anion [Fe(CN)6]3−.  It is also called hexacyanoferrate(III) and in rare, but systematic nomenclature, hexacyanidoferrate(III). The most common salt of this anion is potassium ferricyanide, a red crystalline material that is used as an oxidant in organic chemistry.[1]

Contents

Properties

[Fe(CN)6]3− consists of a Fe3+ center bound in octahedral geometry to six cyanide ligands. The complex has Oh symmetry. The iron is low spin and easily reduced to the related ferrocyanide ion [Fe(CN)6]4−, which is a ferrous (Fe2+) derivative. This redox couple is reversible and entails no making or breaking of Fe-C bonds:

[Fe(CN)6]3− + e− → [Fe(CN)6]4−

This redox couple is a standard in electrochemistry.

Compared to normal cyanides like potassium cyanide, ferricyanides are much less toxic because of the tight hold of the CN- to the Fe3+. They do react with mineral acids, however, to release highly toxic hydrogen cyanide gas.

Uses

Treatment of ferricyanide with ferrous salts affords the brilliant, long-lasting pigment Prussian blue, the traditional color of blueprints.

References

  1. ^ E. Gail, S. Gos, Rupprecht Kulzer, J. L ö rsch, A. Rubo, M. Sauer "Cyano Compounds, Inorganic in Ullmann's Encyclopedia of Industrial Chemistry, 2007, Wiley-VCH, Weinheim. doi:10.1002/14356007.a08 159.pub2

See also