Ferricyanide

Anion in which a Fe3+ ion is complexed by 6 CN− ions
Ferricyanide
Names
IUPAC name
iron(3+) hexacyanide
Systematic IUPAC name
hexacyanidoferrate(III)
Other names
ferric hexacyanide; hexacyanidoferrate(3−); hexacyanoferrate(III)
Identifiers
CAS Number
  • 13408-62-3 checkY
3D model (JSmol)
  • Interactive image
ChEBI
  • CHEBI:5020
ChemSpider
  • 388349 checkY
KEGG
  • C00324
PubChem CID
  • 439210
CompTox Dashboard (EPA)
  • DTXSID70894190 Edit this at Wikidata
InChI
  • InChI=1S/6CN.Fe/c6*1-2;/q6*-1;+3
    Key: YAGKRVSRTSUGEY-UHFFFAOYSA-N
  • N#C[Fe-3](C#N)(C#N)(C#N)(C#N)C#N
Properties
Chemical formula
 [Fe(CN)6]3−
Related compounds
Other cations
 Hexacyanonickelate(III)
Related compounds
 Ferrocyanide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
Chemical compound

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]

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 main group cyanides like potassium cyanide, ferricyanides are much less toxic because of the strong bond between the cyanide ion (CN−) and the Fe3+. They do react with mineral acids, however, to release highly toxic hydrogen cyanide gas.

Uses

Treatment of ferricyanide with iron(II) salts affords the brilliant, long-lasting pigment Prussian blue, the traditional color of blueprints.

See also

References

  1. ^ Gail, E.; Gos, S.; Kulzer, R.; Lorösch, J.; Rubo, A.; Sauer, M.; Kellens, R.; Reddy, J.; Steier, N. "Cyano Compounds, Inorganic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a08_159.pub3. ISBN 978-3527306732.
  • v
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Salts and covalent derivatives of the cyanide ion
HCN He
LiCN Be(CN)2 B(CN)3 C(CN)4
C2(CN)2 		NH4CN
ONCN
O2NCN
N3CN 		OCN−
-NCO
O(CN)2 		FCN Ne
NaCN Mg(CN)2 Al(CN)3 Si(CN)4
(CH3)3SiCN 		P(CN)3 SCN−
-NCS
(SCN)2
S(CN)2 		ClCN Ar
KCN Ca(CN)2 Sc(CN)3 Ti V Cr(CN)63− Mn Fe(CN)2
Fe(CN)64−
Fe(CN)63− 		Co(CN)2
Co(CN)3−
5 		Ni(CN)2
Ni(CN)42−
Ni(CN)44− 		CuCN Zn(CN)2 Ga(CN)3 Ge(CN)2
Ge(CN)4 		As(CN)3
(CH3)2AsCN
(C6H5)2AsCN 		SeCN−
(SeCN)2
Se(CN)2 		BrCN Kr
RbCN Sr(CN)2 Y(CN)3 Zr Nb Mo(CN)84− Tc Ru Rh Pd(CN)2 AgCN Cd(CN)2 In(CN)3 Sn(CN)2 Sb(CN)3 Te(CN)2
Te(CN)4 		ICN Xe
CsCN Ba(CN)2 * Lu(CN)3 Hf Ta W(CN)84− Re Os Ir Pt(CN)42-
Pt(CN)64-
 AuCN
Au(CN)2- 		Hg2(CN)2
Hg(CN)2 		TlCN Pb(CN)2 Bi(CN)3 Po At Rn
Fr Ra ** Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
 
* La(CN)3 Ce(CN)3
Ce(CN)4 		Pr(CN)3 Nd Pm Sm(CN)3 Eu(CN)3 Gd(CN)3 Tb Dy(CN)3 Ho(CN)3 Er Tm Yb(CN)3
** Ac(CN)3 Th(CN)4 Pa UO2(CN)2 Np Pu Am Cm Bk Cf Es Fm Md No