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Prussian blue is a fine, dark blue inorganic pigment known for its high opacity, strong tinting strength, and excellent stability against light and weathering.
Prussian blue is widely used in industrial applications such as paints, coatings, plastics, construction materials, and printing inks due to its durability, chemical resistance, and long-lasting color performance.
Cosmetic- and pharmaceutical-grade Prussian blue is also used in personal care products like eyeshadows and eyeliners because of its vivid hue, non-toxic nature, and safety for topical applications.
CAS Number: 14038-43-8
EC Number: 237-875-5
Molecular Formula: Fe₄[Fe(CN)₆]₃·xH₂O
Molecular Weight: ~859 g/mol
Synonyms: Iron Oxide Blue, Prussian Blue, Ferric Ferrocyanide, Ferric hexacyanoferrate(II), Iron(III) hexacyanoferrate(II), Ferric hexacyanoferrate, Iron blue, Milori Blue, Berlin Blue, Paris Blue, Turnbull’s Blue, Pigment Blue 27, C.I. Pigment Blue 27, C.I. 77510, Ferric hexacyanoferrate hydrate, Iron(III) ferrocyanide, Basic Prussian Blue, Soluble Prussian Blue (pharma grade), Insoluble Prussian Blue, Antidotum Thallii (medical use), Radiogardase® (FDA-approved medicine), Potassium ferric ferrocyanide, Ferric ferrocyanide, hydrated, Iron(III) ferrocyanide, colloidal form, Colloidal Prussian Blue, Ferric ferrocyanide (cosmetic grade), E172 (iron oxides and hydroxides additive), INS 77510, Pigment Blue C.I. 77510, Ferric hexacyanoferrate(II), nonahydrate, Ferric ferrocyanide pigment, Ultramarine substitute (historic), Artificial ultramarine (early synonym), Bleu de Prusse (French), Blau von Berlin (German), Bleu de Paris (historic French), Preußisch Blau (German), Königsblau (royal blue, German context), Chinese Blue (historic trade name), Ferric ferrocyanide complex, Iron(III)-hexacyanoferrate complex, Colloidal iron blue pigment, Hydrated ferric ferrocyanide, Fe₄[Fe(CN)₆]₃ (chemical formula synonym), Ferric ferrocyanide (pharmaceutical quality), Thallium antidote (clinical context), Cesium binder (radiation medicine), Prussian Blue insoluble (pharma additive), Iron(III)–ferrocyanide complex salt, Ferric ferrocyanide blue pigment
Prussian blue typically appears as a fine, dark blue powder with high opacity and excellent stability under normal environmental conditions.
Due to its non-toxic nature and good lightfastness, Prussian blue is widely used in coatings, plastics, inks, paints, and construction materials to impart rich and durable blue shades.
In addition to industrial applications, cosmetic- and pharmaceutical-grade Prussian blue is employed in personal care products, such as eyeshadows and eyeliners, due to its safety and vivid coloring properties.
Prussian blue's chemical resistance, stability, and brilliant hue make it a versatile pigment across both technical and consumer applications.
Iron oxide pigments have been widely used across multiple industries for centuries, offering a range of color options, stability, and non-toxic properties.
Among these, Prussian blue is a distinct pigment known for its brilliant blue hue, derived from a complex iron compound.
Prussian blue now plays a critical role in coatings, construction materials, plastics, cosmetics, and artistic applications.
Prussian blue's chemical stability, environmental safety, and deep coloration make it a preferred choice for formulators seeking high-performance, durable pigments.
Prussian blue typically occurs as a fine, dark blue crystalline powder with high opacity, strong tinting strength, and excellent dispersibility in various media.
Prussian blue is highly valued for Prussian blue's outstanding stability against light, weathering, and alkali exposure, which makes it a reliable choice for both indoor and outdoor applications.
Industrially, Prussian blue is extensively used in paints, coatings, printing inks, and plastics, where it provides durable and vibrant coloration without significant fading over time.
In the construction sector, Prussian blue is applied in concrete, tiles, and flooring materials to achieve long-lasting blue tones.
Beyond industrial use, cosmetic- and pharmaceutical-grade Prussian blue plays an important role in personal care products such as eyeliners, eyeshadows, and nail polishes due to its safety profile and strong coloring effect.
Prussian blue's non-toxic nature, chemical resistance, and environmentally safe characteristics further enhance its value in clean-label formulations and sustainable product lines.
Because of its brilliant hue, versatility, and functional stability, Prussian blue remains one of the most widely used specialty pigments in technical, cosmetic, and consumer markets, bridging both aesthetic appeal and functional performance.
Market Overview of Prussian Blue:
The global market for iron oxide pigments, which includes Prussian blue, is experiencing steady growth driven by rising demand in construction, coatings, plastics, cosmetics, and specialty applications.
Valued at around USD 2.3–2.7 billion in 2023–2024, the market is projected to reach USD 3.4–4.1 billion by 2032–2033, expanding at a CAGR of about 4.5–4.8%.
Among pigment types, synthetic iron oxides account for the majority share (70–80%), favored for their consistency, strong tinting strength, and excellent stability against light and weathering.
Regionally, Asia-Pacific dominates with over 45% of global demand, fueled by rapid urbanization, infrastructure development, and growing consumer markets in China and India.
The construction sector alone represents nearly half of total consumption, while cosmetics and personal care are gaining importance due to the non-toxic and safe profile of pigments like Prussian blue.
Looking ahead, the market is supported by increasing preference for eco-friendly, durable, and non-toxic pigments, alongside continued innovation and capacity expansions by key global players such as LANXESS, Huntsman, DIC, and Cathay Industries.
This combination of performance, safety, and sustainability positions Prussian blue as a key pigment in both industrial and consumer product formulations.
Uses of Prussian Blue:
Prussian blue is widely used as a high-performance pigment across industrial, cosmetic, and consumer applications due to its intense color, stability, and safety profile.
In the construction sector, Prussian blue is incorporated into concrete, cement blocks, paving stones, roofing tiles, and flooring materials to provide durable, long-lasting blue coloration resistant to weathering and UV exposure.
In the paints and coatings industry, Prussian blue is valued for its opacity, tinting strength, and lightfastness, making it suitable for decorative paints, industrial coatings, automotive finishes, and protective applications.
Prussian blue is also employed in the plastics industry, where it delivers strong and stable coloration for packaging, films, pipes, and molded products without affecting processing stability.
In printing inks and paper coatings, Prussian blue ensures vivid and consistent hues that resist fading over time.
Beyond technical uses, cosmetic- and pharmaceutical-grade Prussian blue plays a significant role in personal care products, including eyeshadows, eyeliners, mascaras, nail polishes, and skin creams, where its non-toxic nature and excellent dispersibility ensure both safety and aesthetic appeal.
Thanks to its versatility, durability, and clean-label image, Prussian blue is a preferred pigment for manufacturers seeking reliable performance in both heavy-duty industrial systems and consumer-focused formulations.
Applications of Prussian Blue:
Prussian blue's applications span numerous industries:
Paints and Coatings:
Prussian blue is used in industrial, decorative, and automotive paints due to its UV stability and vivid color.
Prussian blue offers excellent coverage and weather resistance.
Plastics and Polymers:
Added to polyolefins, PVC, and polystyrene to provide coloration without compromising polymer stability.
Requires proper dispersion techniques.
Ceramics and Construction Materials:
Prussian blue is used to color concrete, tiles, and bricks.
Resistant to alkaline environments found in cementitious materials, especially when stabilized.
Cosmetics and Pharmaceuticals:
Approved for use in eye shadows, eyeliners, and therapeutic drugs like radiological decorporation agents.
Must meet purity and particle size specifications.
Artistic and Cultural Heritage Applications:
Prussian blue is used in restoration of historical artworks and monuments.
Preferred for Prussian blue's non-toxic profile and color consistency.
Performance and Compatibility:
Prussian blue demonstrates high performance across various media:
Dispersibility:
Good in water-based and solvent-based systems
Compatibility:
Compatible with resins, polymers, and cements
Durability:
High resistance to weathering, acid rain, and UV radiation
In composite systems, coupling agents and dispersing additives may be used to enhance stability and avoid pigment flooding or floating.
Advantages and Limitations:
Advantages:
Vivid, intense blue color
High tinting strength
Non-toxic and environmentally safe
UV and chemical resistance
Limitations:
Limited thermal stability compared to other pigments
Possible fading in strong alkali environments
Cyanide ligands, though stable, require stringent control in synthesis
Benefits of Prussian Blue:
Prussian blue offers multiple benefits that make it a highly valued pigment in both industrial and consumer applications.
Prussian blue's brilliant deep blue color combined with strong tinting strength allows manufacturers to achieve vivid and uniform shades even at low concentrations, improving formulation efficiency.
Prussian blue demonstrates excellent stability against light, heat, weathering, and chemical exposure, ensuring long-lasting color performance in demanding environments such as outdoor coatings, construction materials, and automotive finishes.
Prussian blue's non-toxic, non-irritating, and environmentally safe profile makes it suitable for use in sensitive applications like cosmetics, personal care products, and pharmaceutical formulations, aligning with global regulatory standards.
Prussian blue also provides outstanding opacity and dispersibility, enhancing coverage and reducing the need for additional pigments.
Furthermore, Prussian blue's compatibility with a wide range of binders, polymers, and surfactants allows flexible use in paints, plastics, inks, and cosmetic emulsions.
By combining durability, safety, and aesthetic appeal, Prussian blue not only improves product performance but also supports the growing demand for eco-friendly and sustainable colorants across industries.
Chemical Composition and Structure of Prussian Blue:
Prussian blue is typically composed of iron(III) ferrocyanide (Fe4[Fe(CN)6]3).
Prussian blue consists of iron in both +2 and +3 oxidation states, forming a crystalline cubic lattice that traps water molecules and ions.
The presence of cyanide ligands in a coordination complex leads to a strong ligand-to-metal charge transfer, resulting in its intense blue coloration.
The crystalline structure is characterized by Fe-CN-Fe linkages that stabilize the overall compound.
This structure allows for ion exchange, making Prussian Blue useful in medical applications as well.
While pure iron oxides (Fe2O3 or Fe3O4) tend to exhibit red, yellow, or black hues, Prussian blue's unique structure gives it optical and chemical characteristics distinct from typical oxides.
Polymorphic forms and hydration levels can affect Prussian blue's tint strength, shade, and stability.
Substitution of metal ions or introduction of stabilizers further modifies Prussian blue's performance characteristics.
Synthesis and Production Methods of Prussian Blue:
The production of Prussian blue can be divided into two broad categories: synthetic and naturally derived.
However, industrially relevant Prussian blue is primarily synthetic due to better purity and consistency.
Co-precipitation Method:
This traditional method involves the reaction of ferric chloride with potassium ferrocyanide in an aqueous medium.
The resulting Prussian blue precipitate is filtered, washed, and dried.
Control over reaction parameters such as pH, temperature, and molar ratios allows tuning of particle size and color intensity.
Hydrothermal and Sol-Gel Techniques:
Modern techniques such as hydrothermal synthesis allow for the development of nano-sized particles with enhanced surface area and improved optical properties.
These methods involve high-temperature, high-pressure reactions in autoclaves.
Calcination and Stabilization:
Post-synthesis, Prussian blue may be stabilized through calcination, often with additives like alumina or silica to enhance its durability.
This step helps improve lightfastness, thermal stability, and dispersibility in various media.
Production:
Prussian blue is produced through a chemical synthesis process that involves the controlled reaction of iron salts with ferrocyanide compounds, resulting in the formation of Prussian blue’s characteristic form.
The production typically begins with soluble ferrous salts, such as ferrous sulfate, which are reacted with potassium ferrocyanide under carefully regulated pH and temperature conditions.
During this process, oxidation converts ferrous ions into ferric ions, yielding the deep blue crystalline pigment.
To achieve high-quality results, Prussian blue undergoes several post-processing steps, including filtration, washing, drying, and micronization, which improve purity, color strength, and dispersibility.
Industrial production may also include surface treatments or encapsulation to enhance heat stability, weather resistance, and compatibility with binders and polymers used in paints, coatings, plastics, and construction materials.
For cosmetic and pharmaceutical applications, Prussian blue is manufactured under stricter safety protocols to ensure compliance with purity standards and the removal of potential impurities such as heavy metals.
This combination of precise chemical control and advanced processing ensures that Prussian blue consistently delivers vivid color, strong tinting power, and durability across diverse applications.
History of Prussian Blue:
Prussian blue is one of the earliest synthetic pigments discovered in human history.
Prussian blue was accidentally discovered in 1704 in Berlin by the colormaker Johann Jacob Diesbach, who was attempting to create a red pigment but instead produced an intense deep blue compound due to the unexpected presence of iron-containing materials in his reagents.
This striking new pigment, far cheaper and more accessible than the precious natural ultramarine derived from lapis lazuli, quickly gained popularity across Europe under the names “Berlin Blue”.
During the 18th and 19th centuries, Prussian blue became a staple in European art and later spread to Asia, where it was famously used in Japanese ukiyo-e woodblock prints, including the works of Hokusai, as well as in masterpieces by European artists such as Vincent van Gogh.
Over time, production methods were refined, allowing for higher purity, consistency, and large-scale manufacturing, which expanded its use beyond art into paints, coatings, plastics, textiles, cosmetics, and pharmaceuticals.
Today, Prussian blue remains an important pigment, prized not only for its brilliant and stable color but also for its safety, versatility, and cultural legacy as the first modern synthetic colorant.
Handling and Storage of Prussian Blue:
Handling:
Handle Prussian blue with care to avoid dust generation and inhalation.
Use in well-ventilated areas or under local exhaust ventilation.
Avoid contact with skin, eyes, and clothing.
Do not eat, drink, or smoke when handling.
Wear appropriate protective equipment such as gloves, safety goggles, and protective clothing.
Wash hands thoroughly after use.
Storage:
Store in tightly sealed containers in a cool, dry, and well-ventilated place.
Protect from direct sunlight, excessive heat, and moisture.
Keep away from strong oxidizing agents and acids.
Containers should remain closed when not in use to prevent contamination and dust release.
Stability and Reactivity of Prussian Blue:
Stability:
Stable under normal temperature and pressure conditions.
Resistant to light, weather, and common environmental factors.
Reactivity:
Incompatible with strong oxidizing agents and concentrated acids, which may lead to decomposition.
Thermal decomposition at very high temperatures may produce hazardous gases such as carbon monoxide, carbon dioxide, and nitrogen oxides.
No hazardous polymerization is expected under normal handling.
First Aid Measures of Prussian Blue:
Inhalation:
Move the affected person to fresh air.
If irritation, coughing, or breathing difficulties persist, seek medical attention.
Skin Contact:
Wash thoroughly with soap and plenty of water.
Remove contaminated clothing and wash before reuse.
Get medical advice if irritation develops.
Eye Contact:
Rinse immediately with clean water for at least 15 minutes, lifting eyelids occasionally.
Seek medical attention if discomfort persists.
Ingestion:
Rinse mouth with water.
Do not induce vomiting unless directed by medical personnel.
Give water to drink and seek medical advice if large amounts are swallowed.
Firefighting Measures of Prussian Blue:
Extinguishing Media:
Use water spray, foam, dry chemical powder, or carbon dioxide depending on the surrounding fire.
Hazards:
Prussian blue itself is not highly flammable, but decomposition at high temperatures can release irritating or toxic fumes (CO, CO₂, NOₓ).
Protective Equipment:
Firefighters should wear self-contained breathing apparatus (SCBA) and full protective clothing.
Accidental Release Measures of Prussian Blue:
Personal Precautions:
Wear suitable protective equipment (gloves, goggles, dust mask). Ensure adequate ventilation and avoid dust formation.
Spill Cleanup:
Sweep or vacuum spilled material carefully to avoid dust dispersal.
Collect into sealed containers for disposal according to local regulations.
Wash spill area with water after cleanup.
Prevent product from entering drains, soil, or waterways.
Exposure Controls / Personal Protection of Prussian Blue:
Engineering Controls:
Provide adequate local exhaust or general ventilation to minimize airborne dust concentrations.
Personal Protection:
Respiratory:
Use an approved particulate respirator if ventilation is inadequate or dust levels exceed exposure limits.
Skin:
Wear chemical-resistant gloves (nitrile, neoprene) and protective clothing.
Eyes:
Wear safety goggles or a face shield.
Body:
Use protective clothing such as lab coat or coveralls to minimize skin contact.
Hygiene Measures:
Do not eat, drink, or smoke during handling.
Wash hands, forearms, and face thoroughly after work.
Remove contaminated clothing and wash before reuse.
Identifiers of Prussian Blue:
Substance Name: Prussian blue
IUPAC Name: Iron(III) hexacyanoferrate(II)
CAS Number: 14038-43-8
EC Number: 237-875-5
Color Index Number: 77510
Molecular Formula: Fe₄[Fe(CN)₆]₃·xH₂O
Molecular Weight: ~859 g/mol
UN Number: Not classified as hazardous for transport
HS Code: 3206.49
PubChem CID: 16211056
InChI: InChI=1S/6CN.7Fe/c61-2;;;;;;;/q6-1;7*+3
InChI Key: WUJFRINCUQJRMN-UHFFFAOYSA-N
Chemical Family: Iron Oxides / Complex Iron Cyanides
Appearance: Fine, deep blue crystalline powder
Odor: Odorless
Substance Name: Prussian blue
IUPAC Name: Iron(III) hexacyanoferrate(II)
CAS Number: 14038-43-8
EC Number: 237-875-5
Color Index Number: 77510
INS / E Number: E 172
Molecular Formula: Fe₄[Fe(CN)₆]₃·xH₂O
Molecular Weight: ~859 g/mol (anhydrous, variable with hydration)
UN Number: Not classified as hazardous / no UN number
HS Code: 3206.49
PubChem CID: 16211056
ChemSpider ID: 17213313
InChI: InChI=1S/6CN.7Fe/c61-2;;;;;;;/q6-1;7*+3
InChI Key: WUJFRINCUQJRMN-UHFFFAOYSA-N
Registry Status: Listed under REACH (EU) and TSCA (US) for industrial and cosmetic use
FDA Status (US): Approved for use as a color additive in cosmetics, including eye-area products, and in externally applied drugs (21 CFR 73.2296)
Properties of Prussian Blue:
Color Index: PB27 (Pigment Blue 27)
Density: ~1.8-2.2 g/cm³
Melting Point: Decomposes before melting
pH in Aqueous Suspension: Neutral to slightly acidic (5.0 - 7.0)
Oil Absorption: Moderate, around 30-50 g/100 g pigment
Thermal Stability: Stable up to ~250°C
Solubility: Insoluble in water and organic solvents
Substance Name: Prussian blue
Appearance: Fine crystalline or amorphous powder, deep blue to dark blue in color
Odor: Odorless
Odor Threshold: Not applicable
Molecular Formula: Fe₄[Fe(CN)₆]₃·xH₂O
Molecular Weight: ~859 g/mol (anhydrous form, varies with hydration)
Color Index (C.I.): 77510 (Pigment Blue 27)
CAS No.: 14038-43-8 / 1345-25-1
pH (aqueous dispersion, 10%): 3.0 – 5.0 (slightly acidic)
Density (Bulk): 1.8 – 2.0 g/cm³
True Specific Gravity: ~1.80 – 1.95
Melting Point / Decomposition: Decomposes > 200 °C (no sharp melting point; releases toxic gases)
Boiling Point: Not applicable (solid compound)
Flash Point: Not flammable
Evaporation Rate: Not applicable
Flammability (solid, gas): Non-flammable
Explosion Limits: Not applicable
Vapor Pressure: Negligible (non-volatile solid)
Vapor Density: Not applicable
Water Solubility: Insoluble in water; partially dispersible as a colloid
Solubility (Other Solvents): Insoluble in alcohol, acetone, most organic solvents
Partition Coefficient (log Kow): Not determined (considered negligible mobility due to insolubility)
Surface Area (BET): ~20 – 50 m²/g (depending on grade)
Refractive Index: ~1.82
Chemical Identity: Prussian blue
Synonyms: CI Pigment Blue 27, CI 77510, Berlin Blue, Milori Blue
Molecular Formula: Fe₄[Fe(CN)₆]₃·xH₂O
Molecular Weight: ~859 g/mol (anhydrous), varies with hydration
Physical State: Solid powder
Appearance: Deep blue to dark blue, fine crystalline or amorphous powder
Odor: Odorless
Taste: Tasteless (not for ingestion except medical-grade antidote use)
Color Index: CI 77510
CAS Numbers: 14038-43-8 / 1345-25-1
EINECS Number: 237-875-5
pH (10% aqueous dispersion): 3.0 – 5.0 (slightly acidic)
Bulk Density: ~0.9 – 1.1 g/cm³
True Density (Specific Gravity): 1.80 – 1.95 g/cm³
Melting Point: Does not have a true melting point; decomposes on strong heating (> 200 °C)
Boiling Point: Not applicable (inorganic pigment, decomposes before boiling)
Decomposition Temperature: > 200 °C (releases CO, CO₂, NOₓ, hydrogen cyanide under extreme conditions)
