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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Oxidising properties

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Administrative data

Link to relevant study record(s)

oxidising liquids
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
Interpretation of results:
GHS criteria not met

Description of key information

Sulphur dioxide does not contain chemical groups associated with oxidising properties. The sulphur atom in sulphuric acid and its salts, has the oxidation number +6. Sulphurous acid (H2SO3) contains sulphur with the oxidation number +4; it has reducing properties and is readily oxidised to sulphuric acid. This behavior is reflected in the electrochemical potential: SO4 2- + H2O + 2 e -> SO3 2- + 2 OH - E = -0,92 V. The UN O.2 test, as described in the UN Manual of Tests and Criteria is based on the reaction of a test compound towards cellulose in comparison to a reference oxidiser. SO3 is the anhydride of sulphuric acid. It is strongly hygroscopic and also acts like an agressive sulfonating agent. SO3 would react exothermally with cellulose. The reaction is not an oxidation but rather a sulfonation and desiccation. Thus, SO3 does not behave like an oxidiser and should not be classified as such.

Key value for chemical safety assessment

Oxidising properties:
non oxidising

Additional information

Justification for classification or non-classification

Sulphur trioxide does not behave like an oxidiser and should not be classified as such.