Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Stability in organic solvents and identity of relevant degradation products

Administrative data

stability in organic solvents and identity of relevant degradation products
Type of information:
experimental study
Adequacy of study:
supporting study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Experimental data was reviewed by the ECETOC Task Force, author of the JACC Report No. 53, “Cyanides of Hydrogen, Sodium and Potassium, and Acetone Cyanohydrin (CAS No. 74-90-8, 143-33-9, 151-50-8 and 75-86-5)”, 2007. The report is a weight of evidence approach to an extensive body of literature, much of which was undertaken prior to development of guidelines. The report was peer reviewed by the scientific non-governmental organization (NGO), which judged the data to be reliable with restrictions.

Data source

Reference Type:
review article or handbook

Materials and methods

Test material

Constituent 1
Chemical structure
Reference substance name:
Hydrogen cyanide
EC Number:
EC Name:
Hydrogen cyanide
Cas Number:
Molecular formula:
hydrogen cyanide

Results and discussion

Test substance stable:

Applicant's summary and conclusion

HCN presents a stable gas in the atmosphere.
Executive summary:

The HCN molecule is strongly bound; it presents a stable gas in the atmosphere. The large enthalpies exclude many theoretically possible endo/exothermic reactions in the gas phase; only those with OH radical and O(1D) are important. Photodissociation is only expected in the upper stratosphere (UV light, λ = 175 - 238 nm).