POTASSIUM FERROCYANIDE

POTASSIUM FERROCYANIDE = POTASSIUM HEXACYANOFERRATE        

CAS Number: 13943-58-3 (anhydrous) / 14459-95-1 (trihydrate)
EC Number: 237-722-2
MDL Number :MFCD00167023
Chemical formula: K4[Fe(CN)6]

Potassium ferrocyanide is the inorganic compound with formula K4[Fe(CN)6]·3H2O. 
Potassium ferrocyanide is the potassium salt of the coordination complex [Fe(CN)6]4−. 
Potassium ferrocyanide forms lemon-yellow monoclinic crystals.
In 1752, the French chemist Pierre Joseph Macquer (1718–1784) first reported the preparation of potassium ferrocyanide, which he achieved by reacting Prussian blue (iron(III) ferrocyanide) with potassium hydroxide.

Potassium ferrocyanide is produced industrially from hydrogen cyanide, ferrous chloride, and calcium hydroxide, the combination of which affords Ca2[Fe(CN)6]·11H2O. 
This solution is then treated with potassium salts to precipitate the mixed calcium-potassium salt CaK2[Fe(CN)6], which in turn is treated with potassium carbonate to give the tetrapotassium salt.
Historically, Potassium ferrocyanide was manufactured from organic compounds containing nitrogen, iron filings, and potassium carbonate. 

 
Potassium ferrocyanide was also obtained commercially from gasworks spent oxide (purification of city gas from hydrogen cyanide).
Treatment of potassium ferrocyanide with nitric acid gives H2[Fe(NO)(CN)5]. 
After neutralization of this intermediate with sodium carbonate, red crystals of sodium nitroprusside can be selectively crystallized.

Prior to 1900 AD, before the invention of the Castner process, potassium ferrocyanide was the most important source of alkali metal cyanides.
In this historical process, potassium cyanide was produced by decomposing potassium ferrocyanide: K4[Fe(CN)6] → 4 KCN + FeC2 + N2
Like other metal cyanides, solid potassium ferrocyanide, both as the hydrate and anhydrous salts, has a complicated polymeric structure. 
The polymer consists of octahedral [Fe(CN)6]4− centers crosslinked with K+ ions that are bound to the CN ligands. 
The K+---NC linkages break when the solid is dissolved in water.

Potassium ferrocyanide is nontoxic, and is not decomposed to cyanide in the body. 
Potassium ferrocyanide is an inorganic compound with the chemical formula K4Fe(CN)6. 
Potassium ferrocyanide is also known as yellow potash prussiate, a yellow crystal. 
Potassium ferrocyanide was made with wool or horn clippings stirring hot potassium carbonate with an iron rod. 

Potassium ferrocyanide was used for certain iron processes as a developer and as an additive for developers of alkaline pyro.
Potassium ferrocyanide is not toxic to humans since Potassium ferrocyanide is not decomposed to cyanide in the body. 
Potassium ferrocyanide (E536) is classified as a neutral salt and is becoming increasingly common in the diet by being added to iodised salt as an anti-caking agent.
Potassium ferrocyanide trihydrate is a salt of the Fe(CN)64- ferrocyanide ion. 
Ferrocyanide is a reducing iron species, being oxidized from ferrous Fe(II) to ferric Fe(III). 

Potassium Ferrocyanide Solution is generally immediately available in most volumes. 
High purity, submicron and nanopowder forms may be considered. American Elements produces to many standard grades when applicable, including Mil Spec (military grade); ACS, Reagent and Technical Grade; Food, Agricultural and Pharmaceutical Grade; Optical Grade, USP and EP/BP (European Pharmacopoeia/British Pharmacopoeia) and follows applicable ASTM testing standards. 

Potassium ferrocyanideis a lemon-yellow, crystalline, water-soluble solid, K4Fe(CN)6⋅3H2O, used chiefly in casehardening alloys having an iron base and in dyeing wool and silk.
Because of the strong chemical bond between iron and the cyanide, usual cooking temperature is unable to break down ferrocyanide to cyanide.  
International food safety authorities have evaluated the safety of sodium/potassium/calcium ferrocyanides and concluded that there is no safety concern in current authorised use and use levels.

Acidity regulator Potassium ferrocyanide, also known as yellow prussiate of potash or potassium hexacyanoferrate(II), is a coordination compound of formula K4[Fe(CN)6]3H2O, which forms lemon-yellow monoclinic crystals at room temperature.
Potassium ferrocyanide forms a stable compound that is neither combustible nor pyrophoric. 
Potassium ferrocyanide is a tough yellow crystalline salt K4Fe(CN)6 made from the cyanogen compounds obtained as by-products in the carbonization of coal or directly by reaction of potassium cyanide with ferrous salts and used chiefly in making iron blue pigments.

Potassium ferrocyanide is an inorganic compound, a cyanide salt of Fe(2+). 
Potassium ferrocyanide is known under E code E 535 and is used in the food industry as an anticaking agent (substances that prevent powdered and granulated ingredients from lumping) in salt. 
Potassium ferrocyanide's absorption from the gastrointestinal tract is low, and there is no accumulation in human.

Potassium Ferrocyanide -K4(Fe(CN))6 is a ferricyanide salt or a potassium salt. 
Potassium ferrocyanide is a colourless or yellowish solid material. 
As a salt, Potassium ferrocyanide is a strong acid salt. 
Potassium ferrocyanide is soluble in water, ether and other solvents.

Potassium ferrocyanide is defined as an inorganic compound having the chemical formula K4(Fe(CN)6) (potassium ferrocyanide formula). 
Potassium ferrocyanide is otherwise called yellow potash prussiate, which is a yellow crystal. 
Potassium ferrocyanide was made with either horn or wool clippings stirring hot potassium carbonate using an iron rod. 
Potassium hexacyanoferrate (II), yellow prussiate of potash are the other names of Potassium Ferrocyanide.

Potassium ferrocyanide is found in the form of yellow, monoclinic crystals having no odor and with a bitter, salty flavor. 
Density of Potassium ferrocyanide is 1.935 at 20 °C.
Potassium ferrocyanide is slightly efflorescent and begins to lose Potassium ferrocyanide's water of crystallization at approximately 60 °C. 
In an oven at 100 °C, Potassium ferrocyanide dehydrates completely, becoming white and hygroscopic.
Freshly prepared aqueous solutions are yellow and decay slowly in light with the release of alkalinity. 
Potassium ferrocyanide take on a greenish color by forming a small quantity of Prussian blue.

In potassium ferrocyanide, the cyanide anion is strongly bonded to ferrous ion and hence does not get hydrolysed.
Potassium ferrocyanide (trihydrate) also known as yellow prussiate of potash with the chemical formula K4Fe(CN)6 · 3H2O. 
Potassium ferrocyanide has the European food additive number E536. 

Together with sodium ferrocyanide and calcium ferrocyanide, potassium ferrocyanide has almost no side effects when used in table salt as a food additive. 
Potassium ferrocyanide has been approved by the European Food Safety Authority (EFSA), Joint FAO/WHO Expert Committee on Food Additives (JECFA) and other authorities.
The chemical bond between iron atom and cyanide in potassium ferrocyanide is stable and strong. 

Potassium ferrocyanide can only be decomposed to potassium cyanide at a higher temperature than 400°C, the cooking temperature is much lower than this temperature to break Potassium ferrocyanide down. 
Potassium ferrocyanide (E536) is listed in Commission Regulation (EU) No 231/2012 as an authorised food additive and categorized as “additives other than colours and sweeteners”. 

Potassium ferrocyanide is an inorganic compound having the chemical formula K4[Fe(CN)6].3H2O. 
Potassium ferrocyanide can be identified as the potassium salt of the ferrocyanide coordination complex. 
Potassium is the cation in this complex while iron-cyanide complex is the anion. 
Potassium ferrocyanide occurs as monoclinic crystals having a lemon-yellow color.
Potassium ferrocyanide compound can be recognized as a non-toxic compound which does not decompose to form cyanide in the body. 

Potassium ferrocyanide is the inorganic compound with formula K4[Fe(CN)6]·3H2O. 
Potassium ferrocyanide is the potassium salt of the coordination complex [Fe(CN)6]4−. 
Potassium ferrocyanide forms lemon-yellow monoclinic crystals.
Together with sodium ferrocyanide and calcium ferrocyanide, potassium ferrocyanide has almost no side effects when used in table salt as a food additive.
K4[Fe(CN)6], or potassium ferrocyanide, is a substance with many different applications. 

USES and APPLICATIONS of POTASSIUM FERROCYANIDE:
-Potassium ferrocyanide finds many niche applications in industry. 
-Potassium ferrocyanide and the related sodium salt are widely used as anticaking agents for both road salt and table salt.
-The potassium and sodium ferrocyanides are also used in the purification of tin and the separation of copper from molybdenum ores.
-Potassium ferrocyanide is used in the production of wine and citric acid.
-Potassium ferrocyanide can also be used in animal feed.

-In the laboratory, potassium ferrocyanide is used to determine the concentration of potassium permanganate, a compound often used in titrations based on redox reactions.
-Potassium ferrocyanide is used in a mixture with potassium ferricyanide and phosphate buffered solution to provide a buffer for beta-galactosidase, which is used to cleave X-Gal, giving a bright blue visualization where an antibody (or other molecule), conjugated to Beta-gal, has bonded to Potassium ferrocyanide's target.

-On reacting with Fe(3) Potassium ferrocyanide gives a Prussian blue colour. 
-Thus Potassium ferrocyanide is used as an identifying reagent for iron in labs.
-Potassium ferrocyanide can be used as a fertilizer for plants.
-Potassium ferrocyanide has many niche uses in industry. 
-Potassium ferrocyanide and the related sodium salt (sodium ferrocyanide) are commonly used for both road salt and table salt as anti creating agents. 

-Used in the tempering of steel and in process engraving.  
Potassium Ferrocyanide is employed in the manufacture of pigments and as a chemical reagent.
-A small amount in pyro and hydroquinone developers tends to lower fog and give greater density.
-Used in the manufacture of potassium cyanide, which is used extensively in gold mining.
-Ferro Cyanogen forms with most metal compounds insoluble in water some of which exhibit highly characteristic colours. 
Potassium Ferrocyanide serves as a test for cupric and ferric compounds.

-Potassium Ferrocyanide can be used in steel tempering and the engraving process. 
-Potassium ferrocyanide is also employed in pigment manufacture and as a chemical reagent.
-A small amount of hydroquinone and pyro developers tends to lower fog and produce greater density.
-Potassium ferrocyanide is also used in potassium cyanide manufacture, which can be extensively used in gold mining.
-Ferro Cyanogen produces the most metal compounds insoluble in water, where a few of them exhibit highly characteristic colours. 
-Potassium ferrocyanide serves as a test for both ferric and cupric compounds.

-Potassium and sodium ferrocyanides are used to purify tin and isolate copper from molybdenum ores. 
-Potassium ferrocyanide is also used for wine and citric acid production.
-Food grade Potassium ferrocyanide is mainly used as food additive, such as: anticaking agent in table salt or used to remove  heavy metal ions (iron, copper, zinc, etc. ) from wine, soy protein...  
-Industry grade Potassium ferrocyanide is mainly used to produce iron blue and potassium ferricyanide, or used in paint, printing ink,  coloring matter, leather industry, pharmacy, heat treatment of metal, metallurgy and other industries. 

-Chemical reagent (Extra Pure) grade Potassium ferrocyanide  is mainly used in high-tech fields such as microelectronics, aerospace. 
-Potassium ferrocyanide in Pharmaceutical industry is used as flocculant,can achieve the ideal in the process, improve the quality of medicine.
-Potassium ferrocyanide is used in steel tempering and process engraving. 
-Potassium ferrocyanide is used in the production of pigments as well as as a chemical reagent.

-In pyro and hydroquinone developers, a small amount of Potassium ferrocyanide tends to reduce fog and increase density.
-Potassium ferrocyanide is used to make potassium cyanide, which is widely used in gold mining.
-Potassium ferrocyanide can be used to detect cupric and ferric compounds.
-Potassium ferrocyanide compound is used in the production of citric acid and wine. 
-Potassium ferrocyanide is also used in animal feeding. 

-Potassium ferrocyanide is used to determine potassium permanganate concentration in the laboratory, which is a compound often used in titrations according to the redox reactions.
-Potassium ferrocyanide is being used in salt to give it anti-caking properties.
-Potassium ferrocyanide is used in drying colors, tempering steel, dyeing, making explosives, process engraving, and lithography;  Used as a food additive, e.g., in wine, to precipitate trace iron and copper.

-Potassium ferrocyanide finds several niche applications in the industry. 
-The related sodium salt is widely used as an anti-caking agent for both table salt and road salt. 
-The sodium and potassium ferrocyanides can also be used in the separation of copper and from molybdenum ores and the purification of tin. 
-Potassium ferrocyanide compound is used in the production of citric acid and wine.
-Potassium ferrocyanide is also used in animal feeding

-Potassium ferrocyanide is used to determine potassium permanganate concentration in the laboratory, which is a compound often used in titrations according to the redox reactions. 
-The potassium ferrocyanide compound is used in a mixture with the phosphate-buffered solution and potassium ferricyanide to give a buffer for beta-galactosidase. 
-Potassium ferrocyanide can be used to cleave X-Gal, producing a bright blue visualisation where an antibody (otherwise another molecule), conjugated to the Beta-gal, has bonded to its target. 

-On reacting with Fe(3), Potassium ferrocyanide produces a Prussian blue colour. 
-Potassium ferrocyanide can be used as an identifying reagent for iron in laboratories.
-Potassium ferrocyanide compound is used as a plant fertilizer.
-Before 1900 AD, prior to the invention of the Castner process, the potassium ferrocyanide compound was the essential source of alkali metal cyanides.

-Potassium ferrocyanide (INS no. 536) as well as sodium and calcium ferrocyanides (535 and 538) can be used as anticaking agents (substances that prevent powdered and granulated ingredients from lumping) in salt under Codex General Standard for Food Additives.  
-Potassium Ferrocyanide is used  in the manufacturing of Ferricyanide, dry colors, tempering steel, dyeing, explosive, process engraving and lithography, as laboratory reagent, for the production of blue pigments (iron blues), as ‘anti-caking agent’ for salt (NaCl), for the precipitation of heavy metal traces (eg. Fe++ in general), for fermentation process of fruit acids (citric acid, tartaric acid etc.), for the purification of wine, for the flotation of ores, in paper industry (security paper), as corrosion inhibitor, in chemical/pharmaceutical industry and in electroplating industry.

-Potassium ferrocyanide is yellow crystalline powder that is used as an etching liquid in electroplating and process engraving. 
-Potassium ferrocyanide is also used as a Fungicide in paper. 
-Additionally, potassium ferrocyanide is used as a colorimetric reagent to detect the presence of Iron or Copper in metals, corrosion products, stains, or pigments. 
Potassium ferrocyanide reacts with iron (III) ions to form ferric ferrocyanide (i.e., Prussian blue) and with copper (II) to form a red-brown cupric ferrocyanide.

-Potassium Ferrocyanide K4(Fe(CN)6) is used in the food and pharmaceutical industries for colouring purposes. 
-The potassium ferrocyanide is used as a colourant in sugar, in food products such as baked goods, pasta, fruit, jelly and pie fillings, dairy products, meat and fish products, coffee, and chewing gum; and as a component in medicines and pharmaceuticals such as vaccines, vitamins, and antibiotics. 
-Potassium ferrocyanide is commonly used in the manufacturing of dry-matter-free foods and food colourants, but there is the increased use of foods containing small amounts of added potassium ferrocyanide. 

-Potassium Ferrocyanide is not a food additive and does not affect food safety. 
-Potassium Ferrocyanide is usually added to sugar to improve the colour of the food product. 
-Potassium Ferrocyanide is approved for use as a colourant in food and as a component of medicines and medical foods for colour control.
-Potassium ferrocyanide is used as a colourant in foods and beverages such as jam, jelly, marmalade, and baking powder. 

-Potassium Ferrocyanide can also be used in some medicines and medicines containing calcium or iron. 
-Potassium Ferrocyanide is also a component of some medical food. 
-Potassium ferrocyanide can also be used to colour some medical foods for specific groups of patients such as those with kidney or cardiac problems.

-There are different important uses of potassium ferrocyanide, including the use of this compound as anticaking agents for both road salt and table salt, in the purification of tin and the separation of copper from molybdenum ores, in the production of wine and citric acid, etc.
-Potassium ferrocyanide -K4(Fe(CN)6) is used as a catalyst in photographic, biochemical and analytical chemistry. 

-Potassium ferrocyanide is mainly used as a potassium salt for the preparation of potassium ferrocyanide - K4(Fe(CN))6. 
-Potassium ferrocyanide - K4(Fe(CN)6) is used in many processes in the analytical laboratory for the detection and determination of metals. 
-Potassium ferrocyanide is used in analytical chemistry for the determination of trace amounts of copper and iron, for the determination of iron in the steel and for the analysis of copper and iron. 

-Potassium ferrocyanide is used to detect the presence of copper in iron ore, the determination of iron and copper in aluminium by atomic absorption and for the identification and determination of copper in a solution. 
-Potassium ferrocyanide is used in analytical chemistry for the determination of arsenic, cadmium, lead and zinc in the determination of arsenic and lead in ore, lead in steel and in steel of all grades.
-The use of potassium ferrocyanide - K4(Fe(CN)6) as an indicator in the precipitation titrimetric procedure is widely known. 

-The reaction is carried out at low pH values in the presence of various bases and the excess of the base is determined by titration with acid. 
-The precipitation with potassium ferrocyanide - K4(Fe(CN)6) in the presence of various metals is also performed.
-The precipitation of iron (II) with potassium ferrocyanide - K4(Fe(CN)6) is used for the identification and determination of iron in iron ore, the determination of iron in the steel and for the identification of copper in an aluminium alloy. 

-The precipitation of aluminium in the presence of potassium ferrocyanide -K4(Fe(CN)6) can be used for the identification and determination of aluminium in an aluminium alloy.
-Potassium ferrocyanide compound can be used for certain iron processes as a developer and as an additive for alkaline pyro developers.

-Potassium ferrocyanide is used to remove iron (III) and iron (II) ions in wines, which could cause iron breakdown. 
-Potassium ferrocyanide is also used to avoid copper breakdown. 
-Potassium ferrocyanide is used, more generally, to reduce the heavy metal content.
-Potassium ferrocyanide is being used in salt to give salt anti-caking properties. 

-Potassium ferrocyanide is commonly used in table salts, also can be used to remove the heavy metal content (e.g. to reduce copper and iron in wine production), production of blue pigments (iron blues), and so on.
-Potassium ferrocyanide can be used as an anticaking agent to improve the fluidity or free-flowing of the salt, and avoid the problem of agglomeration. 
-Potassium ferrocyanide is added by spraying and a very low usage can have a good anti-caking effect. 

-The ferrocyanide species is membrane impermeable and can be used to assess redox activity of membrane-bound structures and mechanisms of electron transport across membranes. 
This approach was employed to demonstrate that Potassium ferrocyanide performs reducing activation of membrane-bound dopamine β-monooxygenase from the exterior face of adrenal vesicles, providing elucidation of native reduction-activation mechanisms for dopamine β-monooxygenase regulation.

-Potassium ferrocyanide is totally different with potassium ferricyanide or potassium hexacyanoferrate(iii), which is an oxidizing agent (iron state Fe3+) commonly used in blueprint drawing, metal treatment and photography instead of in salt.
-Like sodium ferrocyanide, Potassium ferrocyanide is a cyanide salt used as an anticaking agent in table salts to prevent salt granular lumping. 
-Potassium ferrocyanide is known in the EU as the food additive E536, while sodium ferrocyanide Na4[Fe(CN)6] (prussiate of soda) is used in the American food industry.

HOW IS POTASSIUM FERROCYANIDE MADE?
Potassium ferrocyanide is produced by reacting sodium ferrocyanide with calcium hydroxide and potassium carbonate, with the following reactions:
Na4Fe(CN)6 + 2Ca(OH)2 → Ca2Fe(CN)6 + 4Na(OH)
Ca2Fe(CN)6 + 2K2CO3 →  K4Fe(CN)6 + 2CaCO3

Potassium ferrocyanide can also be made from the reaction between calcium cyanide and iron(II) sulfate at a temperature above 100°C: 3CaCN2 + FeSO4 →  Ca2Fe(CN)6 + CaSO4 
And then adds potassium chloride to precipitate the mixed calcium-potassium salt CaK2[Fe(CN)6], which then reacts with potassium carbonate to obtain K4Fe(CN)6 solution. 
The three water crystals form (trihydrate) is obtained by rapid cooling.

The modern production method for potassium ferrocyanide includes the industrial technique, which involves the chemical compounds HCl, FeCl2, and Ca(OH)2. 
The combination of these chemical substances forms a solution which is then treated with potassium salt in order to get the precipitated form of calcium-potassium salt having the chemical formula CaK2[Fe(CN)6].11H2O. 
Thereafter, we need to treat this resulting solution with potassium carbonate in order to get the tetrapotassium salt.

WHAT is the DIFFERENCE between POTASSIUM FERROCYANIDE and POTASSIUM FERRICYANIDE?
Potassium ferrocyanide and potassium ferricyanide are important inorganic compounds. 
These are potassium salts of iron-cyanide coordination complexes. 
The key difference between potassium ferrocyanide and potassium ferricyanide is that potassium ferrocyanide has Fe atom with +2 oxidation state while potassium ferricyanide has Fe atom with +3 oxidation state. 

Furthermore, an easily distinguishable difference between potassium ferrocyanide and potassium ferricyanide is that the potassium ferrocyanide occurs as lemon-yellow colored crystals, while potassium ferricyanide occurs as bright red crystals.

ADVANTAGES of POTASSIUM FERROCYANIDE:
-Potassium Ferrocyanide does not affect food safety.
-Potassium ferrocyanide is water-soluble and stable to hydrolysis and does not generate toxic material.
-Potassium ferrocyanideis highly stable.
-Potassium ferrocyanide does not stain the mouth, lips, teeth or fingers.
-Stains are washable with cold water.

-Potassium ferrocyanide is easy to handle.
-High stability and low melting point.
-Colour is permanent and will not run.
-Colour strength can be varied by adjusting the pH and amount of ingredients.
-Colourants with this property help to produce clear and attractive baked goods.
-Potassium ferrocyanide is a good absorber of moisture from sugar.

-Potassium ferrocyanide does not oxidise rapidly and can be used in large amounts.
-Potassium ferrocyanide is safe for use with children, pregnant women, the elderly, and the sick.
-Potassium ferrocyanide is non-flammable.
-Potassium ferrocyanide has low cost.
-Potassium ferrocyanide does not react with most other food products.
-Potassium ferrocyanide does not alter the taste of the food to which Potassium ferrocyanide is added.

-Potassium ferrocyanide does not harm the environment.
-Potassium ferrocyanide is a good colourant because it gives the product a bright green colour. 
-Potassium ferrocyanide does not lose colour when it is heated or exposed to sunlight.
-Potassium ferrocyanide has fewer disadvantages than a synthetic colourant.
-Potassium ferrocyanide is safe for use in food products.
-Potassium ferrocyanide may be used in a broad range of food products.
-Potassium ferrocyanide is not volatile, so there is no risk of it burning the mouth.

HISTORY of POTASSIUM FERROCYANIDE:
Ferrocyanide salts were first produced in the 1840s. 
Potassium ferrocyanide was produced in 1891 by Thomas Graham and Alfred Rose of the English Pharmaceutical Society. 
This was the first successful commercial production of potassium ferrocyanide. 
Potassium ferrocyanide was first used as a colourant in the food industry in the 1890s. 
Potassium Ferrocyanide was then used to colour gelatin for food products, such as jam and marmalade, to distinguish them from cheaper, synthetic-coloured products. 

Many patents were obtained to protect the new colourant.
Potassium Ferrocyanide was authorised for use of ferrocyanide as a food colouring in the 1930s. 
Potassium Ferrocyanide was approved for use in jelly, jam, marmalade, candy, and baking powder.
There is some dispute about the name potassium ferrocyanide. 
Potassium Ferrocyanide is also known as “green salt.”

CHEMICAL REACTIONS of POTASSIUM FERROCYANIDE:
Treatment of potassium ferrocyanide with nitric acid gives H2[Fe(NO)(CN)5]. 
After neutralization of this intermediate with sodium carbonate, red crystals of sodium nitroprusside can be selectively crystallized.

Upon treatment with chlorine gas, potassium ferrocyanide converts to potassium ferricyanide:
2 K4[Fe(CN)6] + Cl2 → 2 K3[Fe(CN)6] + 2 KCl
This reaction can be used to remove potassium ferrocyanide from a solution.

A famous reaction involves treatment with ferric salts to give Prussian blue. 
With the composition FeIII4[FeII(CN)6]3, this insoluble but deeply coloured material is the blue of blueprinting.

Potassium ferrocyanide will react with  Fe3+  solution to produce a dark blue precipitate called Prussian blue:
K+(aq)+Fe3+(aq)+[Fe(CN)6]4−(aq)↽−−⇀KFe[Fe(CN)6](s)

CHEMICAL PROPERTIES of POTASSIUM FERROCYANIDE:
Potassium ferrocyanide reacts with sulphuric acid in aqueous medium forms potassium sulfate, ferrous sulfate, ammonium sulfate and carbon monoxide.
K4[Fe(CN)6] + 6H2SO4 + 6H2O → 2K2SO4 + FeSO4 + 3(NH4)2SO4 + 6CO

Potassium ferrocyanide reacts with ferric chloride forms a complex compound Iron (III) potassium hexacyanidoferrate(II) and potassium chloride.
K4[Fe(CN)6] + FeCl3 → KFe[Fe(CN)6] + 3 KCl

In the presence of sulphuric acid, potassium ferrocyanide forms potassium sulphate, ferrous sulphate, ammonium sulphate, and carbon monoxide.
K4[Fe(CN)6] + 6H2SO4 + 6H2O → 2K2SO4 + FeSO4 + 3(NH4)2SO4 + 6CO
Iron (III), potassium hexacyanidoferrate(II), and potassium chloride are formed when potassium ferrocyanide reacts with ferric chloride.
K4[Fe(CN)6] + FeCl3 → KFe[Fe(CN)6] + 3 KCl

PHYSICAL and CHEMICAL PROPERTIES of POTASSIUM FERROCYANIDE:
Density: 1.85 g/cm³
Boiling Point: 400 °C
Melting Point: 300 °C
Odour: No odour
Appearance: Light yellow, crystalline granules
Covalently-Bonded Unit: 10
Hydrogen Bond Acceptor: 12
Complexity: 127

Solubility: Insoluble in ethanol, ether
Chemical formula: K4[Fe(CN)6]
Molar mass: 368.35 g/mol (anhydrous) / 422.388 g/mol (trihydrate)
Solubility in water: trihydrate 28.9 g/100 mL (20 °C)
Magnetic susceptibility (χ): −130.0·10−6 cm3/mol
Physical State: Powder Solid
Appearance: Yellow
Odor: Odorless
Odor Threshold: No information available

pH: 9.5 @ 25°C 100g/l aq.sol
Melting Point/Range: 70 °C / 158 °F
Boiling Point/Range: No information available
Flash Point: No information available
Evaporation Rate: Not applicable
Flammability (solid,gas): No information available
Flammability or explosive limits:
*Upper: No data available
*Lower: No data available

Vapor Pressure: negligible
Vapor Density: Not applicable
Specific Gravity: 1.850
Solubility: Soluble
Partition coefficient; n-octanol/water: No data available
Autoignition Temperature: Not applicable
Decomposition Temperature: > 70°C
Viscosity: Not applicable
Molecular Formula: C6 Fe K4 N6 . 3 H2 O
Molecular Weight: 422.4

FIRST AID MEASURES of POTASSIUM FERROCYANIDE:
-Eye Contact:
Check for and remove any contact lenses. 

-Skin Contact:
Wash with plenty of soap and water. 
Remove contaminated clothing and shoes.
Continue to rinse for at least 10 minutes. 
Get medical attention. 

-Inhalation: 
Remove victim to fresh air and keep at rest in a position comfortable for breathing.
Maintain an open airway. 

-Ingestion: 
Wash out mouth with water. 
Maintain an open airway. 
Loosen tight clothing such as a collar, tie, belt or waistband.

ACCIDENTAL RELEASE MEASURES of POTASSIUM FERROCYANIDE:
-Personal Precautions: 
Use personal protective equipment as required. 
Ensure adequate ventilation. 

-Environmental Precautions: 
Do not allow material to contaminate ground water system. 
Collect spillage. 
-Methods for Containment and Clean Up:
Sweep up and shovel into suitable containers for disposal. 

FIRE FIGHTING MEASURES of POTASSIUM FERROCYANIDE:
-Suitable Extinguishing Media:
Substance is nonflammable; use agent most appropriate to extinguish surroundingfire. 
-Unsuitable Extinguishing Media:
No information available

-Sensitivity to Mechanical Impact: No information available
-Sensitivity to Static Discharge: No information available

EXPOSURE CONTROLS/PERSONAL PROTECTION of POTASSIUM FERROCYANIDE:
-Hygiene measures:
Wash contaminated clothing before reusing. 

-Eye/face protection:
Safety eyewear.

HANDLING and STORAGE of POTASSIUM FERROCYANIDE:
-Protective measures: 
Put on appropriate personal protective equipment. 
Do not reuse container.

-Conditions for safe storage, including any incompatibilities:
Store in accordance with local regulations. 
Keep container tightly closed and sealed until ready for use. 
Containers that have been opened must be carefully resealed and kept upright to prevent leakage. 
Do not store in unlabelled containers.
 

STABILITY and REACTIVITY of POTASSIUM FERROCYANIDE:
-Stability: 
Stable under normal conditions.  
-Hazardous Polymerization: 
Hazardous polymerization does not occur. 

SYNONYMS:
yellow prussiate of potash
(Yellow) Prussiate of Potash
Potassium hexacyanoferrate (II) trihydrate
Tetrapotassium ferrocyanide trihydrate
Ferrate hexacyano tetrapotassium trihydrate
Aqueous Potassium ferricyanide 
Potassium hexacyanoferrate(II), 0.1N Standardized Solution 
Potassium hexacyanoferrate(II) 
Iron(2+) potassium cyanide hydrate (1:4:6:3) 
tetrapotassium iron(2+) hexacyanide 
Ferrate(4-), hexakis(cyano-C)-, tetrapotassium
E536    
Ferrate(4-), hexacyano-, tetrapotassium    
Ferrate(4-), hexakis(cyano-C)-, tetrapotassium    
Ferrate(4-), hexakis(cyano-C)-, tetrapotassium, (OC-6-11)-    
Potassium ferrocyanate    
Potassium ferrocyanide    
Potassium hexacyanoferrate    
Potassium hexacyanoferrate(II)    
Tetrapotassium ferrocyanide    
Tetrapotassium hexacyanoferrate
Potassium Ferrocyanide (K4Fe(CN)6)
Potassium hexacyanoferrate (K4Fe(CN)6)
Potassium hexacyanoferrate(4-)
Potassium hexacyanoferrate(II)
Tetrapotassium Ferrocyanide
Tetrapotassium Hexacyanoferrate
Tetrapotassium Hexacyanoferrate(4-)
Tetrapotassium Hexacyanoferrate(II)
Potassium Ferrocyanate
Hexacyano-,Tetrapotassium Ferrate(4-)
Hexakis(cyano-C)-, tetrapotassium Ferrate(4-)
Hexakis(cyano-κC)-, Tetrapotassium Ferrate(4-)
Iron potassium cyanide (FeK4(CN)6)