Material Safety Data Sheet for Tungsten Silicide (WSi₂)

Identification

Product Name: Tungsten Silicide
Chemical Formula: WSi₂
CAS Number: 12039-88-2
Synonyms: Tungsten disilicide
Recommended Use: Semiconductor manufacturing, thin film deposition
Manufacturer Information: Supplier contact details, address, and emergency phone number included on packaging and order documents

Hazard Identification

Classification: Not classified as hazardous according to GHS
Main Hazards: May cause irritation to eyes, skin, and respiratory tract upon exposure to dust or particulates
Pictograms: No GHS pictogram required for bulk form
Signal Word: None
Hazard Statements: Mechanical irritation from inhalation, ingestion, skin, or eye contact with powder or dust
Precautionary Statements: Avoid breathing dust, wash hands thoroughly after use, use appropriate PPE to limit dust contact

Composition / Information on Ingredients

Chemical Name: Tungsten silicide
Common Name: Tungsten disilicide
CAS Number: 12039-88-2
Weight Percentage: 99%+
Impurities: Trace tungsten, silicon, other related metal silicides

First Aid Measures

Inhalation: Move exposed person to fresh air, provide oxygen if breathing is difficult, seek medical care if respiratory symptoms persist
Skin Contact: Remove contaminated clothing, wash skin with soap and water, seek medical attention for persistent rash or irritation
Eye Contact: Rinse eyes with water for at least 15 minutes, keep eyelids open, seek immediate medical attention
Ingestion: Rinse mouth, do not induce vomiting unless directed by medical personnel, seek medical advice promptly

Fire-Fighting Measures

Suitable Extinguishing Media: Use water spray, dry chemical, foam, or carbon dioxide
Unsuitable Extinguishing Media: Avoid direct water stream on dust
Special Fire Fighting Procedures: Firefighters should wear self-contained breathing apparatus and full protective gear
Hazards from Combustion: May release tungsten oxides, silicon oxides, other metallic particulates at high temperatures
Explosion Risk: Not a fire or explosion hazard in bulk form, fine powder can form explosive mixtures with air

Accidental Release Measures

Personal Precautions: Avoid generation of dust, ventilate area
Protective Equipment: Use respiratory protection, eye shield, gloves, and protective clothing
Environmental Precautions: Prevent runoff to drains, waterways, and soil
Cleanup Methods: Collect spilled material without raising dust using dust-hepa filtered vacuum or wet clean-up methods, place in sealed containers for recycling or disposal

Handling and Storage

Handling: Use proper engineering controls to limit dust, handle under local exhaust, avoid breathing dust, avoid contact with skin and eyes
Storage: Store in tightly closed, clearly labelled container in cool, dry, well-ventilated area, away from moisture and incompatible substances
Incompatible Materials: Strong oxidizing agents, strong acids, moist environments

Exposure Controls and Personal Protection

Exposure Limits: No specific limit set for tungsten silicide; for tungsten, ACGIH TLV: 5 mg/m³ (insoluble compounds, as W)
Engineering Controls: Use process enclosures, local exhaust ventilation to minimize airborne dust
Respiratory Protection: NIOSH-approved respirator in dusty conditions
Eye Protection: Safety goggles or face shield
Skin Protection: Protective gloves and clothing to prevent dermal contact
Hygiene Measures: Wash hands before breaks, after handling, remove contaminated clothing, do not eat or drink in work area

Physical and Chemical Properties

Appearance: Silver-gray metallic powder or crystalline solid
Odor: Odorless
Odor Threshold: Not applicable
pH: Not applicable
Melting Point: 2160°C
Boiling Point: >2655°C
Flash Point: Not flammable
Evaporation Rate: Not applicable
Flammability: Non-flammable in solid form
Vapor Pressure: Negligible at room temperature
Vapor Density: Not applicable
Solubility: Insoluble in water
Density: 9.3–9.4 g/cm³
Partition Coefficient: Not applicable
Auto-Ignition Temperature: Not applicable
Decomposition Temperature: Stable up to 1000°C under normal conditions

Stability and Reactivity

Chemical Stability: Stable under recommended storage and handling conditions
Conditions to Avoid: Excessive dust generation, strong acids, moisture
Reactivity: Reacts with strong oxidizers, may form tungsten oxides at high temperatures
Incompatible Materials: Oxidizing agents, halogens, aqua regia
Hazardous Decomposition Products: Tungsten oxides, silicon oxides formed upon heating to decomposition

Toxicological Information

Acute Toxicity: No data for compound, tungsten: oral LD₅₀ (rat) >2000 mg/kg, silicon: low toxicity
Routes of Exposure: Inhalation, skin and eye contact, ingestion
Symptoms: Irritation, cough, redness, sneezing after dust exposure
Chronic Effects: Repeated or prolonged inhalation of dust may cause lung effects, based on tungsten studies
Carcinogenicity: Not listed by IARC, NTP, OSHA
Other Information: No known reproductive or developmental toxicity, not sensitizing by skin contact

Ecological Information

Ecotoxicity: Not expected to be toxic to aquatic environments in solid form
Persistence and Degradability: Inorganic compound, not biodegradable
Bioaccumulation: No data available, unlikely due to low solubility
Mobility in Soil: Low mobility due to water insolubility
Other Adverse Effects: Avoid release to environment, especially in powder form, as heavy metals may persist

Disposal Considerations

Waste Disposal: Dispose of in accordance with local, state, and federal regulations for heavy metal waste
Unused Material: Recover and recycle where possible
Contaminated Packaging: Manage as hazardous waste, ensure it is labeled and sealed
Environmental Precautions: Prevent entry into sewers or waterways

Transport Information

UN Number: Non-regulated material
Transport Hazard Class: Not classified as a hazardous material
Packing Group: Not regulated
Proper Shipping Name: Tungsten silicide
Environmental Hazards: Not a marine pollutant
Special Precautions: Protect from moisture, secure packaging to prevent dust release

Regulatory Information

US Regulations: SARA 313: Not listed, TSCA: Listed
EU Regulations: REACH Status: Registered
Labeling Requirements: Standard workplace hazardous substance labeling
Canada: WHMIS Classification: Not a controlled product
Other Regulations: Workplace exposure must follow OSHA standards and hazard communication rules