Material Safety Data Sheet (MSDS) for Molybdenum Silicide

Identification

Product Name: Molybdenum Silicide
Chemical Formula: MoSi₂
CAS Number: 12136-78-6
Relevant Uses: Heating elements, electronic components, furnace fixtures, high-temperature applications
Manufacturer Contact: Industrial supplier details, including address, phone number, email
Emergency Phone: Local emergency contact numbers provided by the supplier

Hazard Identification

Classification: Not classified as hazardous under GHS
Main Hazards: Dust can irritate eyes, respiratory system, skin; not combustible, but fine powder can pose dust explosion risk under strong oxidizers; chronic exposure may affect lungs
Signal Word: Not required under normal handling
Hazard Statements: Dust may cause mild irritation; possible risk if particles become airborne
Precautionary Statements: Avoid creating dust, use proper ventilation, maintain good hygiene at work, wear protective clothing to prevent skin and eye contact

Composition / Information on Ingredients

Chemical Name: Molybdenum Silicide
Common Synonyms: Disilicide, Moly-disilicide
Concentration: 99% minimum (commercial grade)
Impurities: Trace amounts of molybdenum metal, free silicon, iron, aluminum, and oxygen (usually less than 1%)

First Aid Measures

Inhalation: Move to fresh air, assist breathing if needed, seek medical attention for persistent symptoms such as coughing or difficulty breathing
Eye Contact: Rinse cautiously with water for several minutes, remove contact lenses, continue rinsing if irritation persists, seek medical care for ongoing discomfort
Skin Contact: Wash with soap and water, remove contaminated clothing, seek medical advice if redness or irritation develops and stays
Ingestion: Rinse mouth, drink water if conscious, seek medical advice promptly; avoid inducing vomiting unless directed by medical personnel
Symptoms: Irritation, coughing, redness, or stinging sensation in eyes or on skin, upper respiratory tract discomfort

Fire-Fighting Measures

Flammability: Not combustible in solid state; fine powder can increase risk due to dust suspension
Extinguishing Media: Use dry sand, graphite, or other Class D fire extinguishing agents for metal fires; do not use water or CO₂ on burning powder
Special Hazards: Reacts with strong oxidizers and halogens at high temperatures, which can release irritating gases
Protective Equipment: Use self-contained breathing apparatus and full protective gear for fire control efforts; avoid inhaling dust and fumes during and after a fire
Firefighting Notes: Remove containers from danger zone if safe; avoid dust generation as part of suppression activities

Accidental Release Measures

Personal Precautions: Wear dust mask or respirator, use protective gloves and safety goggles; remove sources of ignition in case of powdered material
Environmental Precautions: Avoid release into waterways and drains; use barriers or absorbent materials to prevent dispersal
Cleanup Methods: Use HEPA vacuum or wet cleaning to collect spill; avoid sweeping or dry-brushing to limit airborne dust; place collected material in sealed container for disposal
Disposal of Spill: Handle collected material as hazardous waste following local rules; do not release into environment

Handling and Storage

Handling: Handle in well-ventilated area, use tools designed to limit dust creation, avoid breathing dust, avoid contact with skin and eyes; keep away from strong acids, oxidizers, and halogens
Storage: Store in tightly closed containers, in a dry location away from moisture; keep away from incompatible materials like chlorine, nitric acid, and other oxidizing agents
Other Precautions: Maintain clean work area, wash hands thoroughly after use, launder contaminated clothing separately

Exposure Controls and Personal Protection

Occupational Exposure Limits: OSHA PEL for nuisance dust: 15 mg/m³ (total); 5 mg/m³ (respirable)
Engineering Controls: Use local exhaust ventilation, enclosures for handling bulk powder, maintenance of equipment for dust control
Personal Protective Equipment (PPE): Wear safety glasses or goggles, dust mask or respirator suitable for particulates (P2 or N95), gloves made of resistant material, protective clothing to cover exposed skin
Hygiene Measures: Wash hands, forearms, and face after handling, remove contaminated work clothes, provide eye-wash stations in workplace

Physical and Chemical Properties

Appearance: Gray to black solid, metallic sheen; available as powder, granules, or pieces
Odor: Odorless
Melting Point: 2,030 °C (3,686 °F)
Boiling Point: Not well defined (compounds decompose)
Density: 6.24 g/cm³
Solubility: Insoluble in water, reacts with molten alkalis
pH: Not applicable
Vapor Pressure: Negligible at room temperature
Flash Point: Not applicable
Auto-Ignition Temperature: Not self-igniting
Other Physical Data: Good electrical conductivity, highly refractory, brittle at room temperature

Stability and Reactivity

Chemical Stability: Stable under normal conditions, does not decompose easily at ambient temperature
Reactive Conditions: Reacts with strong oxidizers, halogens (chlorine, fluorine) at high temperatures; may form toxic gases including MoO₃ and SiO₂ dust under severe oxidation
Hazardous Decomposition Products: Molybdenum trioxide, silicon dioxide, possible release of fine particulates
Polymerization: Not known to occur

Toxicological Information

Routes of Exposure: Inhalation, skin contact, eye contact, ingestion
Short-Term Health Effects: Dust can irritate eyes, airways, and skin; may cause coughing, redness, or dryness
Chronic Health Effects: Prolonged overexposure to dust can lead to respiratory problems and possible lung deposition of particulates; rare reports of long-term effects, though chronic molybdenum toxicity in industrial workers is uncommon at standard exposure levels
Carcinogenicity: No evidence found of carcinogenic effect in animal or human studies (IARC not listed)
Sensitization: Not expected
Target Organs: Lungs, skin, mucous membranes

Ecological Information

Aquatic Toxicity: Not acutely toxic to aquatic organisms at expected environmental concentrations; insoluble, low bioavailability
Persistence and Degradability: Stable mineral compound, does not degrade rapidly; persistence in sediment possible
Bioaccumulation: Low potential due to insolubility
Soil Mobility: Practically immobile, binds to particles in soil, little to no leaching expected
Other Adverse Effects: Considered inert in most environmental settings, but small particles may impact filter-feeding species if discharged in large quantities

Disposal Considerations

Waste Treatment Methods: Collect material for recycling or disposal through approved waste contractor
EPA Waste Number: Not listed as hazardous waste, but local disposal rules for metal-containing compounds still apply
Recommended Disposal: Treat as industrial waste; do not dispose in general waste, soil, sewers, or natural waterways; use sealed containers clearly labeled with contents
Precautionary Disposal Measures: Prevent uncontrolled release, avoid generating or disposing large quantities of powder in open environments

Transport Information

UN Number: Not regulated under standard transportation codes (non-DOT regulated material)
Proper Shipping Name: Molybdenum Silicide
Transport Hazard Class: None governed for bulk solid or articles
Packing Group: Not assigned
Special Precautions: Prevent movement and spillage during transport, ensure containers are secure and labeled, keep away from incompatible substances such as oxidizers
Additional Notes: Check local and international transport rules for fine powders or custom forms

Regulatory Information

TSCA Status: Listed on US Toxic Substances Control Act Inventory
REACH Information: Registered or compliant for use in the EU; not subject to authorization or restriction
Canadian WHMIS: Not classified as hazardous product
SARA 313: Not listed as a reportable toxic chemical
California Proposition 65: Not known to contain chemicals listed
Other Applicable Regulations: Follow workplace safety requirements under OSHA, environmental discharge limits, and local authorities for permitted emissions and waste handling