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CAS Number: 13601-19-9
EC Number: 237-081-9
IUPAC name:Tetrasodium [hexacyanoferrate(II)]
Molecular Weight: 484.06 g/mol
Linear Formula: Na4Fe(CN)6 • 10H2O

E535 (Sodium ferrocyanide) is an odorless yellow solid. 
E535 (Sodium ferrocyanide) sinks and mixes with water.
E535 (Sodium ferrocyanide) is dry powder solid.
E535 (Sodium ferrocyanide) is Pale yellow slightly efflorescent solid.
E535 (Sodium ferrocyanide) is Yellowish crystals.
E535 (Sodium ferrocyanide) also known as yellow prussiate of soda with the chemical formula Na4Fe(CN)6·10H2O. 

E535 (Sodium ferrocyanide) is an anticaking agent. 
E535 (Sodium ferrocyanide) is lemon-yellow monoclinic prismatic or needle-like crystals. 
E535 (Sodium ferrocyanide) is Soluble in water, insoluble in alcohol. 
E535 (Sodium ferrocyanide) is easy to be weathered in the air, and at a temperature of 50 to 60 degrees C, the crystal will quickly lose the water of crystallization. 

Drying is carried out at a higher temperature to form a hard mass and anhydrous.
E535 (Sodium ferrocyanide) is Salt. 
E535 (Sodium ferrocyanide) does not decompose in dilute acid that is not heated, but in concentrated acid that is boiled, free hydrocyanic acid is generated. 
E535 (Sodium ferrocyanide) with silver nitrate causes the formation of milky white silver ferrocyanide precipitation. 
When burning strongly, nitrogen gas is completely decomposed to generate sodium cyanide and iron carbide.

When combined with iron, E535 (Sodium ferrocyanide) converts to a deep blue pigment (Prussian blue). 
Crude sodium cyanide containing some calcium salts, soda ash, and ferrous sulfate is heated in aqueous solution to form the soluble sodium and calcium ferrocyanides. 
During the reaction, calcium carbonate and calcium sulfate precipitate. 
The calcium ferrocyanide is decomposed by the addition of more sodium carbonate, and the slurry is filtered. 

The filtrate is concentrated, and the E535 (Sodium ferrocyanide) crystallizes as the decahydrate, Na4Fe(CN)6•10H2O.
Irradiation with ultraviolet light causes some decomposition at the edges of the crystals of E535 (Sodium ferrocyanide) making them generally more reactive.
E535 (Sodium ferrocyanide) is widely used as an anticaking agent for sodium chloride road salt because E535 (Sodium ferrocyanide) is a crystal modifier that prevents caking at very low levels of addition. 

Cyanide itself is a highly reactive naturally occurring substance that forms compounds ranging in toxicity from innocuous to immediately lethal. 
E535 (Sodium ferrocyanide) is imported into Canada for use on road salt and potentially enters the environment at the producing mines, storage piles or after salt application of roads and streets. 
E535 (Sodium ferrocyanide) is not persistent in the environment and is removed by precipitation, photolysis volatilization, and biological degradation.

E535 (Sodium ferrocyanide) is the raw material for the manufacture of blue pigment, used in paints, coatings and inks. 
E535 (Sodium ferrocyanide) is Used in the printing and dyeing industry to make blue print drawings. 
The pharmaceutical industry is used as a de-ferrous agent in the production of pharmaceuticals. 
Also E535 (Sodium ferrocyanide) is used for steel carburizing, tanning, metal surface anti-corrosion, as well as the preparation of red blood salt.

CAS Number: 13601-19-9
EC Number: 237-081-9
IUPAC name:Tetrasodium [hexacyanoferrate(II)]
Molecular Weight: 484.06 g/mol
Linear Formula: Na4Fe(CN)6 • 10H2O

How is E535 (Sodium ferrocyanide) Made? 

E535 (Sodium ferrocyanide) is a synthetic compound that can be commercially produced by the reaction between sodium cyanide and ferrous sulfate in aqueous medium with heat condition as the following chemical equation indicates:

6NaCN + FeSO4 + Heat →  Na4Fe(CN)6 + Na2SO4 

E535 (Sodium ferrocyanide) decahydrate can be then obtained after the process of crystallization.

E535 (Sodium ferrocyanide) can also be made from the reaction among calcium cyanide, iron(II) sulfate, and sodium carbonate. 

CaCN2 + FeSO4  →  Ca2Fe(CN)6 + CaSO4 
Ca2Fe(CN)6 + 2Na2CO3 →  Na4Fe(CN)6 + 2CaCO3

Functions of E535 (Sodium ferrocyanide):

1. Acidity Regulator / Buffering Agent - Changes or maintains the acidity or basicity of food/cosmetics.
2. Anti-caking Agent - Prevents lumps from forming in food due to excess water. 
They usually function as a water repellent or by absorbing excess moisture.
E535 (Sodium ferrocyanide) is the sodium salt of the coordination compound of formula, E535 (Sodium ferrocyanide) is sometimes known as yellow prussiate of soda. 
E535 (Sodium ferrocyanide) is a yellow crystalline solid that is soluble in water and insoluble in alcohol. 

The yellow color is the color of ferrocyanide anion.
The ferrocyanides are less toxic than many salts of cyanide, because they tend not to release free cyanide. 
However, like all ferrocyanide salt solutions, addition of an acid can result in the production of hydrogen cyanide gas, which is toxic.
When combined with iron, it converts to a deep blue pigment called Prussian blue.
E535 (Sodium ferrocyanide) is used as a stabilizer for the coating on welding rods. 

In the petroleum industry, E535 (Sodium ferrocyanide) is used for removal of mercaptans.
E535 (Sodium ferrocyanide) is approved to use as food additive (E535) in EU.
Anhydrous E535 (Sodium ferrocyanide) starts to decompose in vacuo at 435 °C. giving as products a mixture of sodium cyanide, iron, carbon, and nitrogen.

CAS Number: 13601-19-9
EC Number: 237-081-9
IUPAC name:Tetrasodium [hexacyanoferrate(II)]
Molecular Weight: 484.06 g/mol
Linear Formula: Na4Fe(CN)6 • 10H2O

Sources/Uses of E535 (Sodium ferrocyanide):

E535 (Sodium ferrocyanide) is used in ore flotation, photography (bleaching, toning, and fixing), pickling baths, blue pigments and dyes, blue print paper, metallurgy, and tanning.
Also E535 (Sodium ferrocyanide) is used as a polymerization catalyst, a rock salt anti-caking agent, a peptizing agent in rubber, and an arc stabilizer in welding rod coatings.
E535 (Sodium ferrocyanide) is used as an anti-caking agent for food.
When combined with an Fe(III) salt, E535 (Sodium ferrocyanide) converts to a deep blue pigment called Prussian blue, FeIII4[FeII(CN)6]3.

E535 (Sodium ferrocyanide) is used as a stabilizer for the coating on welding rods. 
In the petroleum industry, it is used for removal of mercaptans.
Ferrocyanide complexes are stable and practically nontoxic because of the strong bonding between iron and cyanide.
Cyanide ions may be formed slowly when the chemical is irradiated with UV light. 
Solutions of E535 (Sodium ferrocyanide) may produce hydrogen cyanide on prolonged exposure to sunlight.
Aqueous solutions of E535 (Sodium ferrocyanide) form hydrogen cyanide when exposed to light.

E535 (Sodium ferrocyanide) may cause irritation.
In the EU, ferrocyanides (E 535–538) were, as of 2018, solely authorized as additives in salt and salt substitutes, where they serve as an anticaking agents. 
Kidneys are the organ for ferrocyanide toxicity, but according to the EFSA, ferrocyanides are of no safety concern at the levels at which they are used.
E535 (Sodium ferrocyanide) (also known as tetrasodium hexacyanoferrate) is a sodium-iron compound used as an anti-caking agent, electroplating additive, and as a petroleum refining reagent.

In photography, E535 (Sodium ferrocyanide) is used for bleaching, toning, and fixing. 
E535 (Sodium ferrocyanide) is used as a stabilizer for the coating on welding rods. 
In the petroleum industry, E535 (Sodium ferrocyanide) is used for removal of mercaptans.

E535 (Sodium ferrocyanide) is used in producing iron blue and potassium ferricyanide, surface corrosion protecting for tannage and metal, carburization treating for carbon steel, removing iron in pharmaceutical producing.
Addition of E535 (Sodium ferrocyanide) solns to slightly acidic solns of iron salts causes precipitation of insol Prussian blue (ferric ferrocyanide), Fe4[Fe(CN)6]3. 
Alkaline solutions yield sol Prussian blue, NaFe[Fe(CN)6]. 
E535 (Sodium ferrocyanide) forms gels with heavy metals in general. 

CAS Number: 13601-19-9
EC Number: 237-081-9
IUPAC name:Tetrasodium [hexacyanoferrate(II)]
Molecular Weight: 484.06 g/mol
Linear Formula: Na4Fe(CN)6 • 10H2O

E535 (Sodium ferrocyanide) applications:

•    Used in ore flotation. 
•    In photography for bleaching, toning, and fixing.
•    To prevent caking of rock salt and foods. 
•    Additive to pickling baths. 
•    Peptizing agent in rubber. 
•    Arc stabilizer in welding rod coatings. 
•    Emulsion polymerization catalyst.

Applications of E535 (Sodium ferrocyanide):

Production of Ferricyanide, blue pigments(Iron blues), blue print paper, as ‘anti-caking agent’ for salt (Nacl), for flotation of ores, pickling of metals, polymerization catalyst, photograph fixing agent, in electroplating industry, food additive, for fermentation processes of fruit acids (citric acid, tartaric acid etc.), as gelating agent for removal of heavy metal traces (Fe++ in general), in pharmaceutical/chemical industry.

Production of E535 (Sodium ferrocyanide):

E535 (Sodium ferrocyanide) is produced industrially from hydrogen cyanide, ferrous chloride, and calcium hydroxide, the combination of which affords Ca2[Fe(CN)6] • 11 H2O. 
A solution of this salt is then treated with sodium salts to precipitate the mixed calcium-sodium salt CaNa2[Fe(CN)6]2, which in turn is treated with sodium carbonate to give the tetrasodium salt.

E535 (Sodium ferrocyanide) is prepared on an industrial scale by reacting hydrogen cyanide with ferrous chloride and calcium hydroxide. 
The solution of this reaction is treated with sodium salts and later with sodium carbonate to create E535 (Sodium ferrocyanide). 
The ferrocyanides are less toxic than many salts of cyanide, because they tend not to release free cyanide.

CAS Number: 13601-19-9
EC Number: 237-081-9
IUPAC name:Tetrasodium [hexacyanoferrate(II)]
Molecular Weight: 484.06 g/mol
Linear Formula: Na4Fe(CN)6 • 10H2O

Properties of E535 (Sodium ferrocyanide):

Category: Metals, Inorganic Compounds
Chemical formula: Na4[Fe(CN)6]
Molar mass: 303.91 g/mol
Appearance:  pale yellow crystals
Odor: odorless
Physical State :Solid
Storage :Store at room temperature
Density: 1.458 g/cm3
Melting point:    435 °C (815 °F; 708 K) (anhydrous)
81.5 °C (178.7 °F; 354.6 K) (decahydrate) (decomposes)
Solubility in water: 10.2 g/100 mL (10 °C)
17.6 g/100 mL (20 °C)
39.7 g/100 mL (96.6 °C)
Insoluble Matter: 0.01% max
Loss on Drying: 1% max. (free moisture)
Solubility in substance:    
Sulfate:  0.07% max
Chloride: 0.1% max
Refractive index (nD):    1.530
Structure of E535 (Sodium ferrocyanide):
Crystal structure: monoclinic
Related compounds:
Other anions: Sodium ferricyanide (Red prussiate of soda)
Other cations: Potassium ferrocyanide
Molecular Weight: 303.91 g/mol
Hydrogen Bond Donor Count: 0    
Hydrogen Bond Acceptor Count: 12    
Rotatable Bond Count:    0    
Exact Mass: 303.912457 g/mol
Monoisotopic Mass: 303.912457 g/mol
Topological Polar Surface Area:    143 Ų    
Heavy Atom Count: 17    
Formal Charge:    0    
Complexity: 127    
Isotope Atom Count:    0    
Defined Atom Stereocenter Count:    0    
Undefined Atom Stereocenter Count:    0    
Defined Bond Stereocenter Count:    0    
Undefined Bond Stereocenter Count:    0    
Covalently-Bonded Unit Count:    11    
Compound Is Canonicalized:    Yes    

Stability/Shelf Life of E535 (Sodium ferrocyanide):

Slightly Efflorescent; Steady Dehydration Occurs Above 50 °C /Decahydrate/
Autoignition Temperature of E535 (Sodium ferrocyanide):
Not flammable

Decomposition of E535 (Sodium ferrocyanide):
When Heated To Decomp Or On Contact With Acid Or Acid Fumes, They Emit Highly Toxic Fumes Of Cyanides. /Ferrocyanides/
Acid, Basic Or Neutral Soln Of Ferrocyanides Liberate Hydrocyanic Acid Upon Strong Irradiation. /Ferrocyanides/

Other Experimental Properties    of  E535 (Sodium ferrocyanide):

SOLUBILITY (G/100 CC WATER): 31.85 G @ 20 °C, 156.5 G @ 98 °C;
INDEX OF REFRACTION: 1.519, 1.530, 1.544; 

Yellow crystals or crystalline powder, the yellow color comes from ferrocyanide anion ([Fe(CN)6]4-), iron is in the state of Fe2+.

Other names of E535 (Sodium ferrocyanide):

Sodium hexacyanoferrate, Tetrasodium hexacyanoferrate

CAS number: 14434-22-1
Chemical formula: Na4Fe(CN)6 · 10H2O
Molecular weight: 484.1 g/mol
Solubility: Soluble in water, insoluble in ethanol

Why does E535 (Sodium ferrocyanide) Used in Table Salts?

E535 (Sodium ferrocyanide) is the cyanide complex and its major purposes in food is as an anticaking agent in salts (table salt, sea salt, iodized and non-iodized salt) for human consumption. 
E535 (Sodium ferrocyanide) is vegan and gluten free.
The surface of crystals of table salt is easy to dissolve after absorbing moisture in air with high humidity, and then recrystallization occurs after water evaporation. 
Finally, caking, lumping, or aggregation occurs.
Some kinds of salt added with small amounts of E535 (Sodium ferrocyanide) to prevent such caking (or clumping) and by reducing the amount of recrystallization through decreasing the solubility of sodium chloride in water.
Is E535 (Sodium ferrocyanide) Safe to Eat?

First of all, please be assured that there are almost no side effects of E535 (Sodium ferrocyanide) when used as a food additive. 
Its safety has been approved by the U.S. Food and Drug Administration (FDA) and European Food Safety Authority (EFSA), as well as the Joint FAO/WHO Expert Committee on Food Additives (JECFA). So please don’t worry about E535 (Sodium ferrocyanide).
The safety concern is generally caused by its chemical name containing cyanide, a known toxin. 

As you can imagine, fears may present in many consumers if they see ferrocyanide (a cyanide complex) listed in the salt label, and that’s why most salt manufacturers prefer to label E535 (Sodium ferrocyanide) as “yellow prussiate of soda”. 
Many salts of cyanide are dangerous, but the cyanide in food grade ferrocyanides is non-toxic as it is tightly bound to an iron atom and so does not tend to release free cyanide. 
In acidic environments, the bonds between sodium and ferrocyanide will break, and the toxic gas – hydrogen cyanide gas will be released , but the stomach acid is a weak acid that cannot promote this reaction in our body.
If you’re still afraid of this ingredient, you can turn to other anticaking agents commonly used in table salts, such as silicon dioxide, sodium silicoaluminate and calcium silicate. 


Yellow prussiate of soda functions as an anticaking agent in salt and as an adjuvant in the production of dendritic crystals with the maximum addition of 0.0013% expressed as E535 (Sodium ferrocyanide) anhydrous. 
E535 (Sodium ferrocyanide) can also be safely used as an anticlumping agent in salt for animal feed. 


E535 (Sodium ferrocyanide) (E535) is listed in Commission Regulation (EU) No 231/2012 as an authorised food additive and categorized as “additives other than colours and sweeteners”. 
Ferrocyanides (potassium ferrocyanide, E535 (Sodium ferrocyanide) and calcium ferrocyanide) are only approved to be used in salt and salt substitutes with the maximum level 20 mg/kg individually or in combination (calculated as potassium ferrocyanide anhydrous). 
Safety re-evaluation in 2018:

EFSA concluded no safety concern at the current authorised use and use levels of E535 (Sodium ferrocyanide) in its safety re-evaluation report in 2018. 
The following are some key points:

Absorption of E535 (Sodium ferrocyanide) in human is low and no accumulation.
No genotoxicity and no carcinogenicity.
Considering the only toxicity of ferrocyanide ion to the kidney, an acceptable daily intake (ADI) of 0.03 mg/kg bw per day (expressed as ferrocyanide ion) was established. 


Function class: food additive, anticaking agent. 
Acceptable daily intake: ADI “0-0.025 mg/kg bw” set in 1974. 
Now you may have an understanding of the food additive – E535 (Sodium ferrocyanide) or Yellow prussiate of soda (E535), from its production; function in table salts; the approved safety; where the health issues come from and the safety of Cyanide in E535 (Sodium ferrocyanide).

CAS Number: 13601-19-9
EC Number: 237-081-9
IUPAC name:Tetrasodium [hexacyanoferrate(II)]
Molecular Weight: 484.06 g/mol
Linear Formula: Na4Fe(CN)6 • 10H2O


Hazard Statements:
Causes serious eye irritation.
Causes skin irritation.
May cause respiratory irritation; or May cause drowsiness or dizziness.

Precautionary Statements:

Call a poison center/doctor/ ... /if you feel unwell.
If eye irritation persists: Get medical advice/attention.
If in eyes: Rinse cautiously with water for several minutes. 
Remove contact lenses, if present and easy to do.
Continue rinsing.
If inhaled: Remove person to fresh air and keep comfortable for breathing.
If skin irritation occurs: Get medical advice/attention.
If skin irritation or rash occurs: Get medical advice/attention.
Take off contaminated clothing and wash it before reuse.
Wash contaminated clothing before reuse.

Avoid dust generation.
Use only outdoors or in a well-ventilated area.
Wash thoroughly after handling.
Wear eye protection/face protection.
Wear protective gloves.
Store in a well-ventilated place. 
Keep container tightly closed.
Dispose of contents in accordance with local, state, regional and federal regulations.
Ingredients of unknown toxicity: 0%

First-Aid Measures of E535 (Sodium ferrocyanide):

Product may cause skin irritation.
It is recommended that prolonged contact with skin be avoided. 
In case of contact with skin, wash skin with soap and water. 
Remove contaminated clothing and wash. 
If symptoms occur, seek medical attention.
E535 (Sodium ferrocyanide) may cause eye irritation. 
It is recommended that direct contact with eyes be avoided. 
In case of contact with eyes, flush eyes with low pressure water for at least 15 minutes. 
If symptoms occur, seek medical attention.
E535 (Sodium ferrocyanide) may cause irritation of respiratory system. 
Avoid dust generation. 
In case of inhalation, remove from contaminated area to fresh air and report situation. 
If allergic response is exhibited, seek medical attention.
If E535 (Sodium ferrocyanide) is swallowed, do NOT induce vomiting. 
Give victim a glass of water or milk. 
Call a physician or poison control center immediately. 
Never give anything by mouth to an unconscious person.
Additional Information:
All treatments should be based on observed signs and symptoms of distress in the patient. 
Consideration should be given to the possibility that overexposure to materials other than the product may have occurred.

Fire Fighting Measures:

Suitable Extinguishing Media
Use an extinguishing agent suitable for the surrounding fire.
Fire-fighting Protective Actions:
Under normal use, no special measures are required. 
If extremely high levels are generated in ambient air, material can support combustion.
Protective Equipment for Fire-fighters:
Fire-fighters should wear appropriate protective equipment.

Accidental Release Measures:

Clean-up: Spilled product should be removed immediately to avoid formation of dust.
Remove by mechanical means (i.e. vacuuming). 
Dilute remainder with plenty of water (avoid formation of aersols). 
Ensure sufficient ventilation. 
Wash contaminated clothing.

Impermeable gloves recommended. 
Safety glasses or goggles. 
None required under usual condition of use.
In case of insufficient ventilation, wear suitable respiratory equipment.

Handling and Storage of E535 (Sodium ferrocyanide):

Handling Avoid formation of dust. 
Ensure good ventiliation of the room when handling E535 (Sodium ferrocyanide).
Avoid splashing and high pressure washing.
Storage Optimal storage conditions:
Store product in original packaging in a cool, dry place. 
Avoid excessive exposure to heat, air and light.

CAS Number: 13601-19-9
EC Number: 237-081-9
IUPAC name:Tetrasodium [hexacyanoferrate(II)]
Molecular Weight: 484.06 g/mol
Linear Formula: Na4Fe(CN)6 • 10H2O


Depositor-Supplied Synonyms:


Tetrasodium hexacyanoferrate

Sodium hexacyanoferrate(II)

sodium hexacyanoferrate(4-)

Sodium prussiate yellow

TetraE535 (Sodium ferrocyanide)

Sodium hexacyanoferate(II)

HSDB 742

Tetrasodium hexacyanoferrate(4-)

EINECS 237-081-9

Ferrate(4-), hexacyano-, tetrasodium

E535 (Sodium ferrocyanide) (Na4(Fe(CN)6))



Ferrate(4-), hexakis(cyano-C)-, tetrasodium



tetrasodium hexacyanidoferrate

sodium hexacyanidoferrate(II)

sodium hexacyanidoferrate(4-)

E535 (Sodium ferrocyanide), AldrichCPR



Ferrate(4-), hexakis(cyano-C)-, tetrasodium, (OC-6-11)-

Ferrate(4-), hexakis(cyano-kappaC)-, tetrasodium, (OC-6-11)-




EC 237-081-9

Ferrate(4-), hexakis(cyano-kappaC)-, sodium (1:4), (OC-6-11)

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