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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Physical & Chemical properties

Vapour pressure

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Description of key information

Vapour pressure [hexachlorodisilane]: 280 Pa at 25°C (QSAR)
Vapour pressure [Hexahydroxydisilane]: <1E-06 Pa at 25 °C (QSAR)
Vapour pressure [Monosilicic Acid]: <1E-06 Pa at 25 °C (QSAR)

Key value for chemical safety assessment

Vapour pressure:
280 Pa
at the temperature of:
25 °C

Additional information

A predicted vapour pressure value of 280 Pa at 25°C, based on a boiling point of 146°C, has been obtained for the substance using a validated QSAR estimation method. The result is considered to be reliable and is selected as key study. In secondary sources to which reliability could not be assigned, a vapour pressure value of 1600 Pa at 20°C was reported for the substance.

The vapour pressure has been obtained for the hydrolysis products using an appropriate calculation method:

Vapour pressure [Hexahydroxydisilane]: <1E-06 Pa at 25 °C (QSAR) - initial hydrolysis product

Vapour pressure [Monosilicic Acid]: <1E-06 Pa at 25 °C (QSAR) - ultimate hydrolysis product

The method has not been validated for inorganic substances but gives an indication of very low vapour pressure. Neither hydrolysis product has been isolated and the predicted values are included for completeness only.