What is Potassium Ferrocyanide E536 in Salt? Uses, Safety, Side Effects 

What is Potassium Ferrocyanide E536 in Salt? Uses, Safety, Side Effects 

What is Potassium Ferrocyanide

Table of Contents

Potassium ferricyanide (E536) is a compound that consists of iron, potassium and TCN. Potassium ferricyanide is generally used as a food additive, often to precipitate out calcium salts in cheese, the taste of which can be rather bitter. 

In baked foods where it acts as a stabilizer and water-retaining agent, potassium ferrocyanide (E535) is used. The following article focuses on what potassium ferricyanide is, as well as its uses, safety and side effects.

What is potassium ferrocyanide?


Potassium ferrocyanide is a salt of iron and potassium. It is used as a food additive for its antioxidant properties, to control acidity, and to enhance the color of food products. Potassium ferrocyanide is also used in the paper industry as a deinking agent.

Potassium ferrocyanide has a molecular formula of KFe(CN)6.2H2O (trihydrate). The molar mass of this compound is 614 g/mol, making it a very heavy compound and one of the densest known solids at room temperature. The crystal structure of potassium ferrocyanide consists of octahedral Fe centers surrounded by six CN ligands and two HO ligands. The coordination environment around each Fe center is octahedral, with each CN occupying two positions on the octahedron and each HO occupying one position on the octahedron.

How to make potassium ferrocyanide?


Potassium ferrocyanide is a chemical compound. It is made from iron, potassium carbonate and hydrocyanic acid. It is used to make a lot of things, including chemicals used to make other chemicals, papermaking chemicals and electroplating chemicals.

Potassium ferrocyanide can be made in different ways with different ingredients. The easiest way to make it is by mixing iron filings or steel wool with potassium carbonate (found in potash) and hydrocyanic acid (HCN for short) together in water. This mixture is heated until the HCN evaporates out of the solution. The remaining solid will be potassium ferrocyanide crystals.

The first step in making potassium ferrocyanide is to mix iron filings or steel wool with potassium carbonate (found in potash) and hydrocyanic acid (HCN for short) together in water. This mixture is heated until the HCN evaporates out of the solution. The remaining solid will be potassium ferrocyanide crystals.

Hydrocyanic acid dissolves the iron or steel wool into iron cyanide: Fe + HCN → FeCN + H 2 O



Odorless lemon yellow crystals with a bitter and salty flavor. Lemon yellow color comes from ferrocyanide anion ([Fe(CN)6]4-) and iron, which is in the state of Fe2+.

Other namesYellow prussiate of potash, potassium hexacyanoferrate ii, tetrapotassium hexacyanoferrate(4–)trihydrate
CAS number14459-95-1
Chemical formulaK4Fe(CN)6 · 3H2O
Molecular weight422.4
SolubilitySoluble in water, insoluble in ethanol

What are the uses of potassium ferrocyanide?


Potassium ferricyanide, also known as potassium ferricyanide, is a chemical compound with the formula K4Fe(CN)6. It is the potassium salt of ferricyanide and is used as a food additive, in various industrial applications, and even as an analytical reagent.

Potassium ferricyanide is used as a food additive for coloring foods such as ice cream, candy and baked goods (e.g. cookies). Because of the risk of choking if swallowed, potassium ferricyanide is not approved for use in foods prepared for children under 12 years of age.

Potassium ferrocyanide is used in the preparation of table salts and other products that are used for cooking purposes. The compound is added to these products so that they have a longer shelf life and add color to them. It can also be used as an ingredient in baked goods such as cookies and cakes, brownies, pretzels and other snacks.

Potassium ferrocyanide is also used in the manufacturing of glass products because it helps strengthen the glass by making it more resistant to breakage. Potassium ferrocyanide can also be found in some paints, as well as in some types of batteries and electrical switches.

Table salts are composed of sodium chloride (NaCl) and potassium chloride (KCl). The combination of these two chemicals creates a salt that dissolves easily in water and has many uses in the kitchen and elsewhere around your home!

Is potassium ferrocyanide safe to eat?


Potassium ferrocyanide is a salt of iron and potassium. It’s used as an anticaking agent in food, cosmetics and detergents. It’s also used as a color stabilizer for foods containing oils and fats.

Potassium ferrocyanide is safe when eaten in food amounts. It’s considered generally recognized as safe (GRAS) by the U.S. Food and Drug Administration (FDA). However, it can be unsafe if it’s inhaled or swallowed in large quantities over a long period of time.

Potassium ferrocyanide is made from iron sulfate, sodium carbonate and potassium hydroxide (lye). It’s added to foods like chocolate syrup, candy, cake mixes and other baked goods to prevent caking when stored for long periods of time at room temperature. Potato chip manufacturers also use potassium ferrocyanide because it helps keep their products from becoming too crispy until they’re sold at the store. The FDA lists it as a food additive that’s permitted for use in meat and poultry products as well as dairy products such as cheese and butter.



Potassium ferrocyanide (E536) is listed as an authorised food additive in Regulation (EU) No 231/2012, categorized as “additions other than colours and sweeteners”. Ferrocyanides are only approved for use in salts and salt substitutes with a maximum concentration of 20 mg/kg (expressed as potassium ferrocyanide anhydrous).



Function class: food additive and anticaking agent.

Acceptable daily intake: In 1974, the ADI was set “0-0.025 mg/kg bw”.

What is potassium ferrocyanide crystals?


Potassium ferrocyanide is a chemical compound that is used in the food industry. It is also used in a number of industrial applications including the manufacturing of dyes and pigments. Potassium ferrocyanide is not naturally occurring but it can be synthesized from iron and potassium cyanide.

Potassium ferrocyanide is a white, crystalline powder that has a bitter taste. It can be found in the form of granules or prills which are irregularly shaped pellets. When potassium ferrocyanide is heated it emits fumes that are toxic to humans and animals. Therefore, you should avoid inhaling these fumes if you work with this chemical regularly.

Potassium ferrocyanide is used in the production of certain types of foods such as breads and baked goods as well as other products such as wine coolers, some pharmaceuticals and other beverages such as sodas and sports drinks.

What is potassium ferrocyanide salt?


Potassium ferrocyanide is a chemical compound with the formula KFe(CN)6. It is used in food processing and in the manufacture of other potassium ferrocyanide derivatives. In lower doses it is used as a nutritional supplement, but in higher doses it can be toxic.

Potassium ferrocyanide was first prepared by Friedrich Wöhler in 1820 by treating potassium cyanide with iron filings. It was not commercially produced until 1881 when the French chemist Henri Moissan prepared it by heating potassium cyanide and iron filings at 500 °C.

It occurs as an odorless white solid that dissolves readily in water and alcohol. The compound has an empirical formula of KCN and a molar mass of 161 g/mol.

What is potassium ferrocyanide synthesis?


Potassium ferrocyanide is a chemical compound with the formula KFe(CN) 6 . It is a bright yellow solid that dissolves in water to give a deep blue solution. Potassium ferrocyanide is used as a food additive, catalyst, and pigment.

Potassium ferrocyanide is produced by the reaction of potassium cyanide with iron(III) oxide or iron(III) chloride in an alkaline solution:

4KCl + Fe2O3 → 2KFe(CN) 6 + 3HCl

The process involves the formation of hexacyanoferrate(III), which decomposes into cyanoferrate(II), Fe(CN) 6 , and hydrogen gas:

2FeCl 3 + 6KCN → 3Fe(CN) 6 + 3KCN + 3HCl

How is potassium ferrocyanide toxicity?


Potassium ferrocyanide is a chemical compound that is used as an ingredient in foods and beverages. It can also be used in the manufacture of jewelry and other products. The substance occurs naturally in some plants and animals, but it can also be produced artificially. Potassium ferrocyanide toxicity occurs when someone consumes too much of this drug or has an allergic reaction to it.

Potassium ferrocyanide toxicity is more likely to occur if you are taking a medication that interacts with potassium ferrocyanide. This is because some medications can increase the effects of this drug in your body, which can cause side effects. Potassium ferrocyanide toxicity may also occur if you consume too much of this substance on its own.

Potassium ferrocyanide vs Potassium ferricyanide


The difference between potassium ferrocyanide and potassium ferricyanide is that potassium ferrocyanide is a salt, and potassium ferricyanide is an oxidizer.

The chemical formula for potassium ferricyanide is K3Fe(CN)6. This compound has many uses in industries such as food processing and textiles, where it helps prevent bacterial growth when stored at high temperatures. It can also be used to treat wastewater and remove ammonia from water sources.

Potassium ferricyanide is also known as potassium ferric hexacyanoferrate(III). It is a yellow solid with the formula KCNFe(CN)6 that dissolves in water to give solutions of varying color between yellow and red depending on concentration. It has been used as a coloring agent for glassware and ceramics since ancient times; at the time it was called “Roman cement”. The name comes from its use: when mixed with iron filings it turns them black due to its ability to catalyze oxidation reactions such as those involving oxygen or nitrogen dioxide gas.

Potassium ferricyanide is an oxidizing agent that contains iron ions and cyanide ions. It can be found in the form of white crystals or powder. Potassium ferricyanide is used in making fireworks during celebrations like New Year’s Eve or Diwali festivals because it produces bright sparks when exposed to open flame such as matches or lighters.

How to prepare potassium ferrocyanide solution?


Potassium ferrocyanide is a compound that can be used as a precursor in the synthesis of several compounds. It is also used in a variety of other applications, such as photography and electroplating. This article describes how to prepare potassium ferrocyanide and its solution from potassium cyanide.

Step 1 – Preparation of Potassium Cyanide Solution

The first step in preparing potassium ferrocyanide solution is the preparation of potassium cyanide solution using sulfuric acid. The sulfuric acid reacts with potassium carbonate in water to produce potassium hydrogen sulfate and potassium hydrogen carbonate, which then react with potassium cyanide to produce sodium sulfate, sodium hydrogen carbonate and sodium hydrogen cyanide. Sodium hydrogen carbonate is insoluble in water, so it separates from the rest of the solution; this leaves behind a solution containing sodium hydrogen cyanide and water.

Step 2 – Preparation of Hydrogen Peroxide Solution

Hydrogen peroxide can be prepared by reacting an acidic solution (such as vinegar) with sodium peroxide or calcium peroxide. In this case, a mixture of vinegar and sodium peroxide is used.

Why potassium ferricyanide is used as external indicator?


Potassium ferricyanide is an external indicator which means that it will change its color only when it comes in contact with the compound to be tested. This makes it a very useful tool for detecting certain elements or compounds in samples without affecting them.

The process of using potassium ferricyanide as an external indicator involves adding some drops of sample solution to a small amount of potassium ferricyanide solution in a glass test tube and observing the color change over time

Potassium ferricyanide reacts with iron ions present in water to form many different compounds, but the most common one is known as Prussian Blue or Iron Blue.

Where to buy potassium ferricyanide?


The internet has become a great resource for buying potassium ferricyanide. You can find it easily in the chemical section of Amazon and eBay.

Amazon has a large selection of Potassium Ferricyanide products, including food grade, laboratory grade and industrial grade.

The prices are generally lower than what you would find at other online retailers and even local stores. The only downside is that some products may be out of stock, especially if they are not in high demand or have a limited supply.

Bulk orders may also be available, but it’s not guaranteed. If you need an order for more than 10 pounds, contact them first before placing your order to make sure that they can fulfill your request.



The Safety concern about potassium ferrocyanide is mostly based on its use as a food coloring agent. However, potassium ferrocyanide is not used as a food coloring agent any more in the Western diet. It has been replaced by safer agents like Blue No. 1 aluminum lake (E131), which is a derivative of ferrocyanide, and other non-toxic colorants. 

The substitute could be due to the cyanide-containing compound that became prohibited following the Second World War. Nonetheless, E536 appears to pose no serious health risk as long as it is consumed in small amounts. It is generally recognized as safe (GRAS) in the US and Blue E131 can also be safely consumed in products that are labeled with this color as an ingredient.

Sophie Feng

Sophie Feng

Sophie Feng is the author of gradechemical.com, she is the co-founder of the grade chemical network. She has been in grade chemical company since 2017, with a working knowledge of food chemical .

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