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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

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Physical & Chemical properties

Vapour pressure

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vapour pressure
Type of information:
other: Data obtained from collection of data
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Principles of method if other than guideline:
Interpolated from a temperature-vapour pressure correlation based on evaluated measured data.
GLP compliance:
Type of method:
other: Temperature-vapour pressure correlation
25 °C
Vapour pressure:
33.2 Pa
110.6 °C
Vapour pressure:
4 060 Pa
Transition / decomposition:

I.   Accepted experimental DIPPR value given. 
    Values given with error of 5%
   Other data cited by DIPPR. Only experimental and accepted values given. Smoothed, rejected and unused data not included.

The coefficients of the temperature-vapor pressure equation for Decamethylcyclopentasiloxane were obtained from critically evaluated experimental data measured over a wide range of temperature. The extrapolated value calculated by the database is comparable to values from other sources and is recognized by AIChE DIPPR as the best available vapor pressure for Decamethylcyclopentasiloxane at 25 ºC.

Description of key information

Vapour pressure: 33.2 Pa at 25°C 

Key value for chemical safety assessment

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

Additional information

A measured vapour pressure of 33 Pa at 25°C, which is based on interpolation from temperature-vapour correction, was reported for the substance in a collection of reliable data which has been subject to peer-review and in which the original data sources are traceable. The result is considered to be reliable and selected as key study. Similarly, measured vapour pressures of 28 Pa and 40 Pa at 20°C and 25°C, respectively, were determined for the substance using the static method (ebulliometer) in accordance with OECD 104 test guideline. Also, a vapour pressure value of 20.4±1.1 at 25°C was determined for the substance using an acceptable scientific method. A vapour pressure of 2 mmHg at 50°C was reported for decamethylcyclopentasiloxane in a supporting handbook or collection of reliable data.

In other secondary sources to which reliability could not be assigned; an extrapolated vapour pressure of 17 Pa at 25°C was reported when fitted into the Antoine equation (Flaningam 1986). Similarly, when the same data was fitted to the AIChE equation, a vapour pressure of 25 Pa at 25°C was obtained. Another source reported a vapour pressure of ca. 23 Pa at 25°C.