Silane

  • Silicon hydride
  • Silicon tetrahydride
Formula SiH4
Structure
Description Gas. Repulsive odor.
Uses Source of hyperpure silicon for semiconductors.

Registry Numbers and Inventories.
CAS 7803-62-5
EC (EINECS/ELINCS) 232-263-4
RTECS VV1400000
RTECS class Mutagen
UN (DOT) 2203
Merck 12,8633
Beilstein/Gmelin 274 (G)
Canada DSL/NDSL DSL
US TSCA Listed
Austrailia AICS Listed
New Zealand Listed
Japan ENCS (MITI) Listed
Korea ECL Listed

Properties.
Formula H4Si(1+)
Formula mass 32.11
Melting point, °C -184.67
Boiling point, °C -107.17
Vapor pressure, mmHg 530 (-118 C)
Vapor density (air=1) 1.13
Density 0.557 g/cm3
Solubility in water Decomposes
Heat of fusion 0.67 kJ/mol

Hazards and Protection.
Storage Store in a cool, dry, well ventilated location. Separate from alkalies, oxidizing materials, halogens, and air. Outside or detached storage is preferred.
Handling All chemicals should be considered hazardous. Avoid direct physical contact. Use appropriate, approved safety equipment. Untrained individuals should not handle this chemical or its container. Handling should occur in a chemical fume hood.
Protection Wear appropriate protective gloves, clothing and goggles. Always wear thermal protective clothing when handling refrigerated/cryogenic liquids.
Respirators Wear positive pressure self-contained breathing apparatus (SCBA).
Small spills/leaks Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Attempt to stop leak if without undue personnel hazard. Use water spray to knock-down vapors.
Stability Stable at ordinary temperature; completely decomp at approx 400 C into silicon and hydrogen; decomp by an electric dischage. he substance may spontaneously ignite on contact with air.
Incompatibilities Reacts with water to form silicon hydroxides and hydrogen gas.
Decomposition The silanes decomposition at elevated temp to liberate hydrogen and deposit a high purity silicon, which leads to some of the principal uses of silanes.

Fire.
Upper exp. limit, % 100
Lower exp. limit, % 1.37
Fire fighting Do not extinguish fire unless flow can be stopped. Do not apply water to point of leak in tank car or container. Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use alcohol foam, dry chemical or carbon dioxide.
Fire potential EXTREMELY FLAMMABLE.
Hazards Silane will ignite spontaneously in air. May polymerize explosively when heated or involved in a fire. Vapors from liquefied gas are initially heavier than air and spread along ground. Vapors may travel to source of ignition and flash back. Containers may explode when heated. Ruptured cylinders may rocket.
Combustion products Fire may produce irritating and/or toxic gases.
NFPA Health 1
  Flammability 4  
  Reactivity 3  

Health.
Exposure limit(s) TLV (as TWA): 5 ppm; 6.6 mg/m3 (ACGIH 1996). NIOSH REL: TWA 5 ppm (7 mg/m3)
Exposure effects
   Ingestion Nausea, vomiting and diarrhea are possible if ingested.
   Inhalation Cough, tachypnea, and wheezing are common after inhalation.
   Skin Redness, swelling and pain may occur.
   Eyes Irritants may cause swelling, redness and pain at any site, especially at mucous membranes. The mouth, nose, and eyes are susceptible to these effects.

First aid		  
   Ingestion Seek medical assistance.
   Inhalation Vapors may cause dizziness or asphyxiation without warning. May be toxic if inhaled at high concentrations.
   Skin Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
   Eyes Flush with running water for at least 20 minutes.

Transport.
UN number 2203
Response guide 116
Hazard class 2.1
Std. Transport # 4905406