Material Safety Data Sheet - Molybdenum Selenide

Identification

Product Name: Molybdenum Selenide
Chemical Formula: MoSe₂
CAS Number: 12058-18-3
Recommended Use: Research, electronics, semiconductor applications
Supplier: Industrial chemical distributor or laboratory supplier
Emergency Contact: Poison Control Center, local emergency services

Hazard Identification

Classification: Not classified as hazardous under GHS guidelines, but dust and particulate forms cause health risks
Routes of Exposure: Inhalation, skin contact, eye contact, ingestion
Hazard Statements: May cause respiratory tract irritation, eye discomfort, skin dryness, harmful if swallowed in larger amounts
Pictograms: Exclamation mark (GHS07)
Signal Word: Warning

Composition / Information on Ingredients

Chemical Name: Molybdenum Selenide
Synonyms: Molybdenum diselenide
Percentage: 99% or greater
Impurities: Trace metal contaminants depending on manufacturing or storage; no known significant impact from minor impurities

First Aid Measures

Inhalation: Move person to fresh air, keep comfortable, seek medical attention if symptoms persist (coughing, difficulty breathing)
Skin Contact: Remove contaminated clothing, wash with soap and water for several minutes, seek medical attention if rash or irritation develops
Eye Contact: Rinse with plenty of water, hold eyelids apart to flush thoroughly for at least 15 minutes, immediate medical help for persistent discomfort
Ingestion: Rinse mouth with water, do not induce vomiting, seek immediate medical advice
General Advice: Show physician this MSDS; symptoms may be delayed

Fire-Fighting Measures

Flammability: Not flammable under normal conditions
Suitable Extinguishing Media: Water spray, carbon dioxide, dry chemical powder, foam
Unsuitable Media: Do not use strong water jets, avoid large volumes that may spread powder
Hazardous Combustion Products: Toxic selenium oxides, molybdenum oxides
Fire-Fighter Protection: Self-contained breathing apparatus, full protective equipment

Accidental Release Measures

Personal Protection: Avoid breath and skin contact, wear dust mask or respirator, goggles, gloves, lab coat
Spill Clean-up: Ventilate area, sweep up avoiding dust formation, place in closed containers for disposal
Environmental Precaution: Prevent runoff to drains, surface water, soil; notification to authorities if significant spill occurs
Decontamination: Flush affected area with water after material removal, clean tools and hands thoroughly

Handling and Storage

Handling: Minimize dust generation, use local exhaust ventilation, handle in fume hood, avoid direct contact, use personal protective equipment
Storage: Store in tightly sealed containers, dry and well-ventilated areas, keep away from oxidizing materials, label containers clearly
Incompatibilities: Strong acids, strong oxidizers, avoid storing with food, beverages or personal items

Exposure Controls and Personal Protection

Exposure Limits: No established OSHA PEL or ACGIH TLV for Molybdenum Selenide; use general dust limits for nuisance particulates (15 mg/m³ total dust, 5 mg/m³ respirable dust)
Engineering Controls: Local exhaust, glove box or fume hood, maintain adequate ventilation
Personal Protection: NIOSH-approved respirator if exposure levels exceed limits, safety goggles, chemical-resistant gloves, lab coat
Hygiene Measures: Wash hands after handling, launder contaminated clothing before reuse, keep eating/drinking areas separate from handling zones

Physical and Chemical Properties

Appearance: Fine powder or crystalline solid, gray-black color
Odor: Odorless
Melting Point: 1200°C-1250°C
Boiling Point: Not available
Solubility: Insoluble in water
Density: Roughly 6.5-7.0 g/cm³
pH: Not applicable
Vapor Pressure: Negligible
Particle Size: Variable, micron to sub-micron ranges depending on source
Other Properties: Stable at room temperature, semi-metallic conductivity

Stability and Reactivity

Chemical Stability: Stable under proper storage conditions
Reactivity: Inert to most environments, can react with strong oxidizing agents
Decomposition: High temperatures create selenium and molybdenum oxides, which are hazardous
Potential Hazards: Exposure to strong acids increases risk of toxic gas release

Toxicological Information

Acute Effects: Dust irritation to eyes, skin, respiratory tract; harmful if swallowed in significant quantities
Chronic Effects: Prolonged or repeated exposure to selenium compounds affects liver, kidneys, and nervous system; molybdenum can impact respiratory health
LD50 Data: No reliable animal or human oral/dermal LD50 data specific for MoSe₂; reference similar compounds for rough estimates
Potential Effects: May cause headaches, metallic taste, garlic breath odor, skin rashes, low-level exposure is unlikely to provoke significant symptoms

Ecological Information

Aquatic Toxicity: Selenium-containing compounds are highly toxic to aquatic life at elevated concentrations; molybdenum less so, but accumulation in sediment is possible
Persistence: Not readily biodegradable, persistent in soil and water
Mobility: Insoluble, doesn’t migrate easily in groundwater; fine particulate can disperse by wind or surface wash-off
Bioaccumulation: Selenium accumulates in fish and aquatic organisms, strict local discharge limits apply to selenium waste

Disposal Considerations

Methods: Collect in labeled, tightly closed containers; contact licensed waste disposal service; disposal in accordance with local, national, and international regulations for hazardous waste
Precautions: Do not pour down the drain, avoid landfill unless treated as hazardous waste
Contaminated Packaging: Dispose of packaging in a safe manner after ensuring it's empty and risk-free of residual dust

Transport Information

UN Number: Not classified as a dangerous good for transport
Transport Hazard Class: None assigned
Packaging Group: None assigned
Special Precautions: Keep sealed, avoid rough handling to prevent dust release; comply with all carrier and local authority requirements

Regulatory Information

Chemical Inventory Status: Listed or exempted on TSCA, REACH, DSL, EINICS
Labeling: Comply with OSHA Hazard Communication, GHS regulations
Environmental Regulations: Follow local, state, and federal rules for selenium discharges and airborne particulates
Worker Protection: OSHA, NIOSH, ACGIH personal protection requirements apply; annual safety training on handling and disposal