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EC number: 213-603-0
CAS number: 993-07-7
Trimethylsilane is a gas at
standard temperature and pressure, with melting point of -135.9°C and
boiling point of 6.7°C. The requirement to conduct a relative density
study was waived because the substance is a gas; a density value of 3.1
kg/m3 at 20°C was calculated for the substance on the basis
of molecular weight of 74.2 g/mol and Ideal Gas Laws. The vapour
pressure of the substance is expected to be greater than the limit of
measurement, i.e. >1E+05 Pa at 20°C, due to the boiling point of the
The substance is classified as an
extremely flammable gas according to Regulation (EC) No. 1272/2008. This
is on the basis of a measured Lower Flammability Limit and Upper
Flammability Limit of 1.38 (vol%) in a 5 litre chamber and 51.3 (vol%)
in a 1 litre chamber respectively, at 25°C and 1013 hPa. It has a
measured auto-ignition temperature of 245°C.
On the basis of structural
examination, the substance is not considered to be surface active, it is
not oxidising and does not have any of the chemical structures that are
associated with explosive properties.
In contact with water
trimethylsilane reacts slowly (half-life of about 3 days at 24.7°C) to
produce trimethylsilanol and hydrogen according to the following
+ H2O → (CH3)3SiOH + H2
Trimethylsilane has a predicted
log Kow of 2.2 at 20°C. Measurement of the solubility in
water of the substance is considered technically not feasible because
trimethylsilane is a gas under standard conditions of temperature and
pressure, with an expected vapour pressure of >1E+05 Pa.
The silanol hydrolysis product,
trimethylsilanol, has the potential to form dimers in solution. The
concentration of trimethylsilanol in water may be determined by this
condensation reaction rather than by the solubility of trimethylsilanol
itself. It has a measured solubility of 995 mg/l at 20°C and a measured
log Kow of 1.19 at 20°C and is not surface active. Trimethylsilanol
has a measured vapour pressure of 1290 Pa at 20°C and 1900 Pa at 25°C.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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