Material Safety Data Sheet: Molybdenum Dioxide

Identification

Product Name: Molybdenum Dioxide
Chemical Formula: MoO₂
CAS Number: 18868-43-4
Synonyms: Molybdenum(IV) oxide
Recommended Use: Used in ceramic, glass, chemical, and electronic industries as a pigment, catalyst, or advanced material intermediate
Supplier: Manufacturer address and emergency contact information available through product packaging and internal safety program
Emergency Phone: The number established locally for chemical emergencies and poison control

Hazard Identification

Classification: Not classified as hazardous by GHS standards, but dust may irritate the respiratory tract, eyes, and skin
Signal Word: Not applicable
Hazard Statements: Breathing dust can cause mild to moderate nose and throat irritation, extended skin contact causes dryness or small abrasions, and dust in eyes may scratch corneal tissue
Precautionary Statements: Avoid generating dust, use with adequate ventilation, wash hands after handling, and use eye/face/skin protection as needed
HMIS Ratings: Health: 1, Flammability: 0, Reactivity: 0, Personal Protection: B

Composition / Information on Ingredients

Chemical Name: Molybdenum Dioxide
Common Name: MoO₂
Concentration: >98% (as MoO₂), trace impurities may include MoO₃ and unreacted elemental molybdenum
Impurities: No substances classified as hazardous above relevant thresholds

First Aid Measures

General Advice: Remove contaminated clothing and wash skin thoroughly
Inhalation: Move person to fresh air, seek medical attention if symptoms persist especially in cases of excessive coughing or shortness of breath
Skin Contact: Wash hands and affected areas with soap and water, consult physician if irritation develops or persists
Eye Contact: Flush eyes with gentle stream of water for at least 15 minutes, keeping eyelids apart to remove fine particles, seek medical evaluation if irritation continues
Ingestion: Rinse mouth, drink water to dilute, seek medical advice if feeling unwell, never induce vomiting except on medical advice
Most Important Symptoms/Effects: Mechanical irritation due to fine particulate, scratchiness or redness in eyes, dry or chapped skin, coughing

Fire-Fighting Measures

Suitable Extinguishing Media: Use dry chemical, foam, carbon dioxide, or water spray for surrounding fire
Unsuitable Extinguishing Media: None specific; powder is not combustible
Hazardous Combustion Products: May evolve molybdenum oxides under high temperatures
Protective Equipment: Firefighters should wear standard protective clothing and self-contained breathing apparatus
Advice for Firefighters: Cool exposed containers with water spray, avoid inhaling dust or combustion gases, contain runoff to prevent deposit in drains and the environment

Accidental Release Measures

Personal Protection: Wear appropriate respiratory protection for high dust concentrations, don gloves and goggles
Environmental Precautions: Prevent spillage from entering waterways and soil, contain to reduce dust dispersion, use local exhaust ventilation to minimize total airborne dust
Cleanup Methods: Sweep up material gently using a broom and dustpan or HEPA-filtered vacuum, avoid dry sweeping if dust is visible, place waste in labeled container for recycling or disposal, ensure area is ventilated and residue is wet-mopped

Handling and Storage

Safe Handling: Minimize airborne dust by handling in enclosed processes or within fume hoods, avoid ingestion and breathing of particles, maintain good industrial hygiene and routine hand washing
Storage Requirements: Store in tightly closed containers, keep out of direct sunlight and away from oxidizing agents, secure against physical damage, maintain stability by keeping dry and at ambient room temperatures
Incompatibilities: Avoid mixing with strong oxidizers or acids, as reactivity increases and could cause hazardous decomposition

Exposure Controls and Personal Protection

Engineering Controls: Provide local exhaust ventilation at sources of dust formation, process enclosures, routine dust collection, exhaust air filtration
Exposure Limits: OSHA PEL for insoluble compounds, 5 mg/m³ (respirable fraction); ACGIH TLV 10 mg/m³ total dust
Personal Protective Equipment: Safety goggles for eye protection, gloves (nitrile or neoprene), NIOSH-approved dust mask or respirator if exposure may exceed limits, laboratory coat, and closed footwear in areas of bulk handling
Hygiene Measures: Wash hands after handling and before eating, clean clothing routinely, maintain workplace cleanliness with regular wet cleaning

Physical and Chemical Properties

Appearance: Black or dark grey powder or crystals
Odor: Odorless
Odor Threshold: Not applicable
pH: Not soluble in water
Melting Point: 1,100°C
Boiling Point: Decomposes before boiling
Flash Point: Not flammable
Evaporation Rate: Not applicable
Flammability: Not flammable
Vapor Pressure: Negligible
Vapor Density: Not applicable
Solubility: Insoluble in water, slightly soluble in strong acids
Partition Coefficient (n-octanol/water): Not determined
Auto-Ignition Temperature: Not available
Decomposition Temperature: Above 1,100°C
Viscosity: Not applicable
Bulk Density: Approximately 6.47 g/cm³

Stability and Reactivity

Chemical Stability: Stable under normal temperature and storage conditions, low hazard of decomposition unless strongly heated or in contact with incompatible materials
Reactivity: No significant reactivity with common materials
Incompatible Materials: Strong oxidizing agents, strong acids, especially hot concentrations, can accelerate oxidation or cause violent reaction at elevated temperatures
Hazardous Decomposition Products: Forms other molybdenum oxides in high heat; releases small amounts of toxic molybdenum fumes in fire
Possibility of Hazardous Reactions: Unlikely under normal industrial or laboratory practices

Toxicological Information

Routes of Exposure: Inhalation, skin, eye, ingestion
Acute Effects: Dust particles can cause irritation, especially respiratory and ocular; ingestion in high quantities leads to gastrointestinal irritation
Chronic Effects: Extended or repeated exposure may lead to mild respiratory discomfort, no conclusive links to severe chronic toxicity, occupational studies show mild gastrointestinal symptoms from overexposure
LD50/LC50: Data for MoO₂ not precisely established; related molybdenum compounds have low acute toxicity
Carcinogenicity: Not classified as a carcinogen by IARC, OSHA, NTP, or ACGIH
Mutagenicity: No evidence found from permitted use
Reproductive Effects: No significant effects found in animal studies at normal exposure levels

Ecological Information

Environmental Fate: Not readily soluble, accumulates in sediments and soils
Persistence and Degradability: Inorganic compound, not degradable by microbial action
Bioaccumulative Potential: Low; limited bioaccumulation observed for molybdenum ions
Ecotoxicity: Molybdenum ions can become toxic to plants and aquatic organisms in high concentrations; avoid uncontrolled spills
Mobility in Soil: Low mobility owing to insolubility in neutral environmental conditions
Other Adverse Effects: May impact soil microflora if over-applied, especially in sensitive ecological areas
Regulatory Status: No classification as marine pollutant under international transport regulations

Disposal Considerations

Disposal Methods: Collect and place residues in marked, securely sealed containers, send for disposal at licensed hazardous material facilities or metals recycling operations depending on local regulation
Contaminated Packaging: Clean thoroughly before reuse, or dispose of as hazardous waste
Special Precautions: Prevent environmental release, use government-approved waste collectors, never dispose in municipal waste or down the drain
Waste Codes: Follow local, regional, and national hazardous waste guidelines; standardized waste codes for inorganic metal compounds may apply

Transport Information

UN Number: Not regulated by DOT, ADR, IATA, or IMDG
Proper Shipping Name: Molybdenum Dioxide
Transport Hazard Class: Not classified as hazardous for transport
Packing Group: Not assigned
Environmental Hazards: Avoid exposure to marine environments due to possible heavy metal contamination
Special Transport Precautions: Avoid package rupture or dust emission, use sturdy containers and labeling

Regulatory Information

OSHA: Listed as a dust nuisance, no listed permissible limit for MoO₂, but observe standards for total/nuisance dust
TSCA: Listed in the U.S. Toxic Substances Control Act Inventory
SARA Title III: Not an extremely hazardous substance
California Proposition 65: Not identified on Cal/Prop 65 as cancer or reproductive toxin
EINECS/ELINCS: Listed
Canadian WHMIS: No classification required, handle under routine industrial hygiene
Other Regulations: Reach registered in Europe; keep up-to-date with local requirements for reporting and notification