Potassium ferricyanide
You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.
| Potassium ferricyanide | |
|---|---|
| Image:Potassium ferricyanide.jpg | |
| Image:Potassium-ferricyanide-sample.jpg | |
| IUPAC name | Potassium hexacyanoferrate(III) |
| Other names | Red prussiate Prussian red Potassium ferricyanide |
| Identifiers | |
| CAS number | |
| RTECS number | LJ8225000 |
| Properties | |
| Molecular formula | C6N6FeK3 |
| Molar mass | 329.24 g/mol |
| Appearance | red solid |
| Density | 1.89 g/cm3, solid |
| Melting point |
(? K) |
| Boiling point |
decomp. |
| Solubility in water | 33 g/100 mL ("cold water") 77.5 g/100 ("hot water")[1] |
| Structure | |
| Crystal structure | monoclinic, |
| Coordination geometry | octahedral |
| Hazards | |
| Main hazards | toxic |
| R-phrases | 32 |
| S-phrases | none |
| Related Compounds | |
| Other anions | Potassium ferrocyanide |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references | |
Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [1] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.
Overview
Potassium ferricyanide is the chemical compound with the formula K3[Fe(CN)6]. This bright red salt consists of the coordination compound [Fe(CN)6]3−.[1] It is soluble in water and its solution shows some green-yellow fluorescence.
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
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) [1] 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.[1]
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.[1] 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.[1][1]
References
External links
- International Chemical Safety Card 1132
- National Pollutant Inventory - Cyanide compounds fact sheetcs:Hexakyanoželezitan draselný
de:Kaliumhexacyanidoferrat(III) fr:Ferricyanure de potassium it:Ferricianuro di potassio nl:Kaliumhexacyanoferraat (III) ja:フェリシアン化カリウムsk:Hexakyanoželezitan draselný
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
