Quick Search
CAS Number: 51274-00-1
EC Number: 215-168-2
C.I. Number: 77492
Molecular Formula: Fe₂O₃·H₂O (or FeOOH)
Molecular Weight: 159.69 g/mol (as Fe₂O₃)
Synonyms:
Yellow iron oxide; Iron(III) oxide-hydroxide; Ferric oxide monohydrate; Hydrated ferric oxide; Yellow ferric oxide; Iron oxide yellow monohydrate; Transparent iron oxide yellow; C.I. 77492; Pigment Yellow 42; Yellow iron oxide pigment; Goethite (mineral form); Synthetic yellow iron oxide
Chemical Identity and Properties:
C.I. Pigment Yellow 42 is an inorganic synthetic pigment consisting of hydrated iron(III) oxide. The compound crystallizes in the orthorhombic system as the mineral goethite (α-FeOOH). The needle-like (acicular) particle morphology contributes to its tinting strength, dispersibility, and optical properties. The pigment is available in both opaque and transparent varieties, with transparent grades having finer particle sizes (typically <0.1 µm) that exhibit higher transparency and greater color intensity.
Physical Properties:
Appearance: Yellow to reddish-yellow powder, odorless
Specific Gravity: 5.24 g/cm³
Melting Point: 1538 °C (decomposes)
Bulk Density: 0.5–1.0 g/cm³ (varies by grade)
pH (10% slurry): 3.0–7.0 (varies by grade and surface treatment)
Oil Absorption: 25–35 g/100 g pigment
325 Mesh Residue: ≤0.3–0.5% (opaque grades)
Water Soluble Content: ≤0.3–0.5%
Loss on Drying (105 °C): ≤1.0%
Loss on Ignition (800 °C): ≤14%
Pigment Characteristics:
Lightfastness: Excellent (8 on the blue wool scale)
Weather Resistance: Excellent
Heat Stability: Stable up to 300 °C (transparent grades) and 800 °C (opaque grades)
Chemical Resistance: Resistant to dilute acids, alkalis, and solvents
Opacity: Ranges from semi-opaque to fully opaque depending on particle size
Color Index: Classified as a high-performance inorganic pigment
Manufacturing Process:
Synthetic yellow iron oxide is produced through controlled precipitation and oxidation processes:
1. Precipitation Method:
Iron(II) sulfate (copperas) is dissolved in water
Neutralized with alkali (sodium hydroxide or calcium hydroxide) to form iron(II) hydroxide
Oxidized with air or oxidizing agents under controlled conditions to form iron(III) oxide-hydroxide
2. Penniman Process (Variation):
Involves the use of iron scrap and iron(II) sulfate in the presence of an oxidizing agent
Produces acicular (needle-shaped) particles with superior pigmentary properties
3. Post-Treatment:
The precipitated pigment is filtered, washed to remove soluble salts
Dried under controlled conditions to achieve the desired hydration state
Milled to achieve the required particle size distribution
May be surface-treated to enhance dispersibility and compatibility with various media
Applications:
1. Paints and Coatings:
C.I. Pigment Yellow 42 is extensively used in:
Architectural paints: Interior and exterior decorative paints
Industrial coatings: Primers, topcoats, and corrosion-inhibiting formulations
Automotive coatings: Primers and undercoats
Marine coatings: Anticorrosive and decorative marine paints
Powder coatings: Durable, weather-resistant finishes
Coil coatings: Pre-painted metal products
2. Construction Materials:
Cement products: Concrete blocks, paving stones, roof tiles, bricks, and masonry
Mortars and plasters: Colored mortars, renders, and stucco
Asphalt: Colored asphalt for decorative paving
Sports surfaces: Colored running tracks and sports surfaces
3. Plastics and Polymers:
Thermoplastics: PVC, polyolefins (PE, PP), polystyrene, ABS, polycarbonate
Engineering plastics: Nylon, polyesters, polyacetals
Thermosets: Unsaturated polyesters, epoxies, polyurethanes
Rubber: Natural rubber, SBR, EPDM for automotive and industrial products
Masterbatches: Color concentrates for plastics
4. Cosmetics and Personal Care:
Cosmetic-grade yellow iron oxide (C.I. 77492) is used in:
Face products: Foundations, concealers, powders, BB creams, CC creams
Eye products: Eyeshadows, eyeliners, mascaras, brow products
Lip products: Lipsticks, lip glosses, lip balms
Nail products: Nail polishes and enamels
SAFETY INFORMATION ABOUT C.I. PIGMENT YELLOW 42
First aid measures:
Description of first aid measures:
General advice:
Consult a physician.
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
If inhaled:
If breathed in, move person into fresh air.
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off contaminated clothing and shoes immediately.
Wash off with soap and plenty of water.
Consult a physician.
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Continue rinsing eyes during transport to hospital.
If swallowed:
Do NOT induce vomiting.
Never give anything by mouth to an unconscious person.
Rinse mouth with water.
Consult a physician.
Firefighting measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment.
Avoid breathing vapours, mist or gas.
Evacuate personnel to safe areas.
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Methods and materials for containment and cleaning up:
Soak up with inert absorbent material and dispose of as hazardous waste.
Keep in suitable, closed containers for disposal.
Handling and storage:
Precautions for safe handling:
Avoid inhalation of vapour or mist.
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place.
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles.
Faceshield (8-inch minimum).
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
Skin protection:
Handle with gloves.
Gloves must be inspected prior to use.
Use proper glove
removal technique (without touching glove's outer surface) to avoid skin contact with this product.
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices.
Wash and dry hands.
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
Body Protection:
Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection:
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls.
If the respirator is the sole means of protection, use a full-face supplied air respirator.
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions.
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company.
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product
