Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Melting point / freezing point

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
melting point/freezing point
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Guideline:
other: Not reported
Type of method:
other: Not reported
Key result
Melting / freezing pt.:
16.8 °C
Atm. press.:
ca. 101 325 Pa
Conclusions:
The melting point of sulphur trioxide is 16.8 °C
Executive summary:

The melting point of sulphur trioxide is reported to be 16.8 °C. However, it should be noted that the different polymerised forms of the substance have different melting points: α form (62.4 °C), β form (32.5 °C), γ form (16.8 °C). Melted sulphur trioxide usually exists in the γ form.

Description of key information

The melting point of sulphur trioxide is reported to be 16.8 °C. However, it should be noted that the different polymerised forms of the substance have different melting points: α form (62.4 °C), β form (32.5 °C), γ form (16.8 °C). Melted sulphur trioxide usually exists in the γ form.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
16.8 °C

Additional information