Potassium ferricyanide

Potassium ferricyanide

Chembox new
Name = Potassium ferricyanide
ImageFile = Potassium ferricyanide.jpg
ImageSize = 250px
ImageName = Potassium ferricyanide
ImageFile1 = Potassium-ferricyanide-sample.jpg
ImageSize1 = 250px
ImageName1 = Crystals of potassium ferricyanide
IUPACName = Potassium hexacyanoferrate(III)
OtherNames = Red prussiate
Prussian red
Potassium ferricyanide
Section1 = Chembox Identifiers
CASNo = 13746-66-2
RTECS = LJ8225000
Section2 = Chembox Properties
Formula = C6N6FeK3
MolarMass = 329.24 g/mol
Appearance = red solid
Density = 1.89 g/cm3, solid
Solubility = 33 g/100 mL ("cold water")
77.5 g/100 ("hot water") [Kwong, H.-L. "Potassium Ferricyanide" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.]
MeltingPt = (? K)
BoilingPt = "decomp."
Section3 = Chembox Structure
Coordination = octahedral
CrystalStruct = monoclinic,
Section7 = Chembox Hazards
MainHazards = toxic
RPhrases = 32
SPhrases = none
Section8 = Chembox Related
OtherAnions = Potassium ferrocyanide

Potassium ferricyanide is the chemical compound with the formula K3 [Fe(CN)6] . This bright red salt consists of the coordination compound [ferricyanide| [Fe(CN)6] 3−] . [Sharpe, A. G., The Chemistry of Cyano Complexes of the Transition Metals, Academic Press: London, 1976] It is soluble in water and its solution shows some green-yellow fluorescence.

3 K+

Preparation

Potassium ferricyanide is manufactured by passing chlorine through a solution of potassium ferrocyanide. Potassium ferricyanide separates from the solution::2K4 [Fe(CN)6] + Cl2 → 2K3 [Fe(CN)6] + 2KCl

Applications

In 19th century was used for reading palimpsests and old manuscripts [ [http://www.skypoint.com/~waltzmn/ShortDefs.html#Chemicals Chemicals at the Encyclopedia of Textual Criticism] ] . The compound has widespread use in blueprint drawing and in photography (Cyanotype process). Iron and copper toning involve the use of potassium ferricyanide. Potassium ferricyanide is used as an oxidizing agent to remove silver from negatives and positives, a process called dot etching. In color photography, potassium ferricyanide is used to reduce the size of color dots without reducing their number, as a kind of manual color correction. The compound is also used to temper iron and steel, in electroplating, dyeing wool, as a laboratory reagent, and as a mild oxidizing agent in organic chemistry.It is also used in photography with sodium thiosulfate (hypo) [ The Focal Encyclopedia of Photography By Leslie D. Stroebel, Richard D. Zakia [http://books.google.co.uk/books?id=CU7-2ZLGFpYC&pg=PA297&lpg=PA297&dq=farmers+reducer&source=web&ots=d8tOCFXuht&sig=lSQ3oo0vHek3tO_uefk9hWkNDsg&hl=en ] ] ] to reduce the density of a negative where the mixture is known as Farmer's reducer; this can help offset problems from overexposure. Variants of Farmer's reducer can also be used as the intermediate step in reversal photography to dissolve the silver image produced by the first development.

Potassium ferricyanide is also one of two compounds present in ferroxyl indicator solution (along with phenolphthalein) which turns blue (Prussian blue) in the presence of Fe2+ ions, and which can therefore be used to detect metal oxidation that will lead to rust. It is possible to calculate the number of moles of Fe2+ ions by using a colorimeter, because of the very intense color of Prussian blue Fe4 [Fe(CN)6] 3.

Potassium ferricyanide is often used in physiology experiments as a means of increasing a solution's redox potential (Eo' ~ 436 mV at pH 7). Sodium dithionite is usually used as a reducing chemical in such experiments (Eo' ~ −420 mV at pH 7).

Potassium ferricyanide is the main component of Murakami's etchant for cemented carbides.

Prussian blue

Prussian blue, the deep blue pigment in blue printing, is generated by the reaction of K3 [Fe(CN)6] with ferrous (Fe2+) ions. [Dunbar, K. R.; Heintz, R. A., "Chemistry of Transition Metal Cyanide Compounds: Modern Perspectives", Progress in Inorganic Chemistry, 1997, volume 45, 283-391.]

In histology, potassium ferricyanide is used to detect ferrous iron in biological tissue. In this reaction, potassium ferricyanide reacts with ferrous iron in acidic solution to produce an insoluble blue pigment, and both the stain and the pigment are commonly referred to as Turnbull's blue. To detect ferric (Fe3+) iron, potassium "ferrocyanide" is used instead; the stain and pigment produced are commonly known as Prussian blue. [Carson, Freida L. (1997). "Histotechnology: A Self-Instructional Text" (2nd ed.), pp. 209-211. Chicago: American Society of Clinical Pathologists. ISBN 0-89189-411-X.] It has been found that the compound formed in the Turnbull's blue reaction and the compound formed in the Prussian blue reaction are the same unique compound, Prussian blue. [Tafesse, F. (2003). [http://www.mdpi.org/ijms/papers/i4060362.pdf Comparative studies on Prussian blue or diaquatetraamine-cobalt(III) promoted hydrolysis of 4-nitrophenylphosphate in microemulsions] . "International Journal of Molecular Sciences", "4"(6): 362-370.] [Verdaguer, M., Galvez, N., Garde, R., & Desplanches, C. (2002). Electrons at work inPrussian blue analogues. "Electrochemical Society Interface", "11"(3): 28-32.]

References

External links

* [http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc11/icsc1132.htm International Chemical Safety Card 1132]
* [http://www.npi.gov.au/database/substance-info/profiles/29.html National Pollutant Inventory - Cyanide compounds fact sheet]


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  • Potassium ferricyanide — Ferricyanide Fer ri*cy a*nide (?; 104), n. [Ferri + cyanide.] (Chem.) One of a complex series of double cyanides of ferric iron and some other base. [1913 Webster] {Potassium ferricyanide} (Chem.), red prussiate of potash; a dark, red,… …   The Collaborative International Dictionary of English

  • potassium ferricyanide — kalio heksacianoferatas(III) statusas T sritis chemija formulė K₃[Fe(CN)₆] atitikmenys: angl. ferric potassium cyanide; potassium ferricyanide; potassium hexacyanoferrate; red potassium prussiate; red prussiate of potash rus. калия… …   Chemijos terminų aiškinamasis žodynas

  • potassium ferricyanide — noun : a red crystalline salt K3Fe(CN)6 made by oxidizing potassium ferrocyanide with chlorine and used chiefly as a photographic bleach and in coating blueprint paper called also red prussiate of potash * * * Chem. a bright red, crystalline,… …   Useful english dictionary

  • potassium ferricyanide — Chem. a bright red, crystalline, water soluble, poisonous solid, K3Fe(CN)6, used chiefly in the manufacture of pigments, as Prussian blue, and of paper, esp. blueprint paper. Also called red prussiate of potash. * * * …   Universalium

  • potassium ferricyanide — deep red crystals used in Drabkin solution to test for hemoglobin …   Medical dictionary

  • potassium ferricyanide — (K3Fe(CN)6)    Bright red, lustrous crystals or powder. Used for tempering steel; etching liquid; production of pigments; electroplating and fertilizer compositions …   Forensic science glossary

  • potassium ferricyanide — /pəˌtæsiəm fɛriˈsaɪənaɪd/ (say puh.taseeuhm feree suyuhnuyd) noun a red crystalline solid, K3Fe(CN)6, used in the manufacture of pigments …  

  • Ferricyanide — is the name for the anion [Fe(CN)6] 3−. Its systematic name is hexacyanoferrate(III) ion. The most common salt of this anion is potassium ferricyanide, a red crystalline material that is used as an oxidant in organic chemistry. [Fe(CN)6] 3−… …   Wikipedia

  • Ferricyanide — Fer ri*cy a*nide (?; 104), n. [Ferri + cyanide.] (Chem.) One of a complex series of double cyanides of ferric iron and some other base. [1913 Webster] {Potassium ferricyanide} (Chem.), red prussiate of potash; a dark, red, crystalline salt,… …   The Collaborative International Dictionary of English

  • Potassium ferrocyanide — chembox Name = Potassium ferrocyanide ImageFile = Potassium ferrocyanide trihydrate sample.jpg ImageSize = 250px ImageName = Potassium ferrocyanide trihydrate IUPACName = Potassium hexacyanoferrate(II) OtherNames = Tetrapotassium ferrocyanide,… …   Wikipedia

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