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Description of key information

Key value for chemical safety assessment

Additional information

No measured data are available for trichlorosilane.

Trichlorosilane contains no chromophores that would absorb visible or UV radiation, so direct photolysis is not likely to be significant. Trichlorosilane hydrolyses very rapidly (half-life ≤ 0.3 min at pH 7 and 25°C) therefore, reaction with water vapour, rather than photolysis, is expected to be the primary degradation process in air. The initial hydrolysis product is silanetriol, which is expected to react rapidly (expected half-life <12 hours at pH 7 and 25°C) to monosilicic acid [Si(OH)4], which condenses at concentrations above approximately 100-150 mg/l as SiO2to give a dynamic equilibrium between monomer, oligomers and insoluble amorphous polysilicic acid

These hydrolysis products are inorganic substances which enter natural biogeochemical cycles.