Silane is a chemical compound with formula SiH4. It is the silicon analogue of methane. At room temperature, silane is a pyrophoric gas: it undergoes spontaneous combustion in air without the need for external ignition.
Several industrial and medical applications exist for silane and functionalised silanes. For instance, silanes are used as coupling agents to adhere glass fibres to a polymer matrix, stabilising the composite material.
A number of fatal industrial accidents produced by detonation and combustion of leaked silane in air have been reported. Diluted silane mixtures with inert gases such as nitrogen or argon are even more likely to ignite when leaked into open air, compared to pure silane. Even a 1% mixture of silane in pure nitrogen easily ignites when exposed to air.
Silane is reported to have a repulsive smell.
Silane Characteristics
Synonyms
Silicon tetrahydride, Monosilane
CAS No.
7803-62-5
Chemical formula
SiH4
Vapour density
1.11 (air = 1)
Safe Work Australia ES
TWA
5 ppm
STEL
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Flammable limits
LEL
Spontaneously flammable in air
UEL
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Equipment group
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Temperature classification
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Chemical/physical properties
Silane is a colourless, pyrophoric (spontaneously flammable) gas at room temperature with a repulsive odour.
Hazardous properties
Apart from being a serious fire risk, silane is considered to be mildly toxic by inhalation and irritating to the skin, eyes and mucous membranes.
Occurrence/Uses
The main use of silane is as a doping agent in the production of semiconductors.
