Material Safety Data Sheet: Diborane

Identification

Product Name: Diborane
Chemical Formula: B₂H₆
Synonyms: Boron hydride, Boron hydrogen
CAS Number: 19287-45-7
Recommended Use: Chemical synthesis, doping agent in semiconductor manufacture, rocket propellant research
Supplier Details: Distributed by most industrial gas suppliers, detailed on shipment labels
Emergency Contact Number: Refer to national poison center or local emergency line, usually noted on supplier paperwork

Hazard Identification

GHS Classification: Flammable gas (Category 1), Acute toxic inhalation (Category 1), Pyrophoric gas
Hazard Statements: Highly flammable, severe inhalation hazard, decomposes to toxic boron oxides, reacts violently with oxidizers
Pictograms: Flame, Skull and crossbones, Gas cylinder
Signal Word: Danger
Major Risks: Immediate asphyxiation, severe respiratory damage, possible explosion in air
Precautionary Measures: Do not inhale, keep away from heat, sparks, open flames, avoid release to environment
Routes of Exposure: Inhalation, skin contact, eye contact
Symptoms: Coughing, chest tightness, dizziness, irritation of eyes and mucous membranes, confusion, chemical burns

Composition / Information on Ingredients

Chemical: Diborane
Percentage: 100% by volume for industrial cylinders, diluted blends available
Impurities: Trace levels of boron trihydride, diboron tetrahydride can occur based on manufacturing method
Molecular Weight: 27.67 g/mol
EC Number: 242-859-5
Relevant Identifiers: UN Number 1911 for transport, varies in specific countries based on regulation

First Aid Measures

Inhalation: Remove person to fresh air immediately, provide 100% oxygen by mask, seek urgent medical help
Skin Contact: Remove contaminated clothing, flush skin with copious water for at least 15 minutes, wash gently with soap
Eye Contact: Rinse eyes cautiously with water for several minutes, remove contact lenses if present and easy to do, continue rinsing
Ingestion: Not expected due to gaseous form, but if exposure occurs, do not induce vomiting; seek medical assistance
Additional Actions: Medical professionals should monitor for chemical pneumonitis, pulmonary edema, severe burns; supportive care may include intubation and administration of corticosteroids
Note: Rescue should not take place without full protective gear and self-contained breathing apparatus due to extreme inhalation risk

Fire-Fighting Measures

Suitable Extinguishing Media: Stop gas flow if safe; dry powder extinguisher or carbon dioxide for small fires, water spray for large quantities to reduce vapors
Unsuitable Media: Do not use water jets directly on gas jets, avoid halogenated extinguishing agents
Special Fire Hazards: Flash point below room temperature, can autoignite in air, burns with a green flame, generates toxic boron oxides
Firefighter Equipment: Full-turnout gear plus self-contained breathing apparatus required
Explosive Limits: Lower explosive limit 0.8%, upper limit 88% in air
Thermal Decomposition: Releases hydrogen gas, boron oxide, and other toxic fumes at high temperatures
Firefighting Methods: Cool surrounding containers to prevent rupture, isolate hazard area, apply non-sparking tools, consider evacuation

Accidental Release Measures

Personal Precautions: Evacuate all non-essential personnel, ventilate area, eliminate ignition sources
Protective Equipment: Self-contained breathing apparatus, chemical-resistant suit, nitrile gloves, face shield
Environmental Protection: Prevent gas from spreading to sewers or confined spaces, notify local authorities
Containment Methods: Shut off gas source if possible; use water spray to absorb escaping vapors and suppress cloud
Cleanup Procedures: Local exhaust ventilation, trained personnel only, collect and dispose of any solid residues as hazardous waste, monitor air with gas detectors during remediation
Special Instructions: If the release is significant, seal area and allow dissipation in atmosphere, monitor downwind for exposure

Handling and Storage

Handling: Use only in controlled environments with adequate ventilation, employ closed systems for gas transfer, ground and bond all containers and lines
Safe Work Practices: No smoking or open flames in gas handling areas, inspect lines and fittings regularly for leaks with soapy water
Storage: Store cylinders upright, in cool, dry, and well-ventilated specialized gas cabinets, segregate from oxidizers and acids
Temperature Control: Avoid temperatures above 50°C or below recommended minimums, protect from direct sunlight
Pressure Precautions: Do not drop or damage cylinders, use regulators specifically rated for diborane
Maintenance: Train workers in emergency procedures, post warning signage in storage and handling zones

Exposure Controls and Personal Protection

Exposure Limits: OSHA Permissible Exposure Limit (PEL) 0.1 ppm, ACGIH Threshold Limit Value (TLV) 0.1 ppm (TWA)
Engineering Controls: Use gas cabinets with mechanical ventilation, gas leakage detection systems, fume hoods or ventilated enclosures
Personal Protection: Air-supplied respirators for possible exposure, chemical splash goggles, flame-resistant coveralls, double nitrile gloves, safety boots
Hygiene Practices: Wash hands and arms thoroughly after handling, no food or drinks in work area, routine monitoring with personal gas detectors
Medical Surveillance: Baseline lung function and periodic health checks for exposed workers recommended

Physical and Chemical Properties

Appearance: Colorless, highly flammable gas, faint unpleasant odor resembling ether or garlic
Molecular Weight: 27.67 g/mol
Melting Point: -165°C
Boiling Point: -92.5°C
Vapor Pressure: 3,550 mmHg at 21°C
Solubility: Slightly soluble in cold water, more in organic solvents
Density: 1.16 g/L at 0°C
Odor Threshold: 2 to 5 ppm
Evaporation Rate: Rapid due to low boiling point
Autoignition Temperature: 38°C
Explosive Properties: Forms explosive mixtures with air, wide flammable range
Decomposition Products: Hydrogen gas, boron oxides, on heating or contact with moisture

Stability and Reactivity

Chemical Stability: Unstable at room temperature without pressure containment
Reactivity: Reacts violently with air, oxygen, halogens, oxidizers
Conditions to Avoid: Heat, sparks, static discharge, incompatible chemicals (chlorine, water vapor, acids)
Decomposition: Hydrolyzes to form boric acid and hydrogen, releases boron trioxide under thermal stress
Polymerization: Not reported to undergo hazardous polymerization under normal conditions
Incompatibility: Nitric acid, peroxides, strong bases and acids

Toxicological Information

Acute Toxicity: LC₅₀ in rats at 10 ppm/4 hr, extremely toxic by inhalation
Effects of Exposure: Upper and lower respiratory tract irritation, pulmonary edema, headaches, seizures at higher doses
Routes: Inhalation is most significant, with moderate skin and eye absorption
Chronic Effects: Repeated low level exposure linked to bronchitis, nosebleeds, dry cough, anemia
Carcinogenicity: Not classified as a human carcinogen
Other Effects: Reproductive toxicity shown in animal studies, not well established in humans
Sensitization: Not reported; caution due to corrosive nature on tissues
Target Organs: Lungs, mucous membranes, skin

Ecological Information

Environmental Impact: Highly toxic to aquatic life, especially due to rapid hydrolysis products
Persistence and Degradability: Hydrolyzes quickly on contact with moisture, forms boric acid which persists longer
Biodegradability: Not readily biodegradable; slow boron cycle breakdown in soil/water
Bioaccumulation Potential: Low bioaccumulation expected for parent compound
Mobility: High mobility as gas, settles in low-lying areas, significant potential for off-site drift
Water Hazard Rating: Classified as hazardous to water sources, prompt response required

Disposal Considerations

Waste Disposal: Always treat as hazardous waste, seek out specialized hazardous gas incinerators or chemical neutralization by qualified professionals
Cylinder Disposal: Return partially filled or empty cylinders to supplier, do not vent or incinerate on site
Containment: Prevent entry to water courses or drains, use chemical trapping only as last resort
Legal Regulations: All local, state, and federal waste regulations apply; consult environmental health and safety departments
Spill Management: Absorb solid residues with inert material, collect in sealed drums for disposal under hazmat protocols

Transport Information

UN Number: 1911
Shipping Name: Diborane, compressed gas
Transport Hazard Class: Hazard Class 2.3: toxic gas, subsidiary Class 2.1: flammable gas
Packing Group: Not assigned due to gas status
Labeling Requirements: Toxic gas label, flammable gas label
Special Precautions: Double-walled packaging frequently required, keep cylinders upright and secure, compliance with IATA, IMDG, DOT regulations mandatory
Emergency Guide Number: Reference Emergency Response Guidebook (ERG) for spills and leaks during transit

Regulatory Information

OSHA: Listed as hazardous and regulated under Process Safety Management (PSM) in the U.S.
EPCRA: Reportable quantity for accidental releases; notification to EPA and local response teams
TSCA: All components listed or compliant
REACH/CLP (EU): Strict registration and use conditions, authorization required, listed as a major accident hazard chemical
State Regulations: California Proposition 65: not listed, workplace exposure standards enforced
Chemical Facility Requirements: Site security, inventory reporting, and risk assessment protocols under national regulations
Transport Regulations: Classified under international dangerous goods lists, detailed documentation required throughout supply chain