Substance Information - ECHA - European Union

The ‘Substance identity’ section is calculated from substance identification information from all ECHA databases. The substance identifiers displayed in the InfoCard are the best available substance name, EC number, CAS number and/or the molecular and structural formulas.

Some substance identifiers may have been claimed confidential, or may not have been provided, and therefore not be displayed.

EC (European Community) Number

The EC Number is the numerical identifier for substances in the EC Inventory. The EC Inventory is a combination of three independent European lists of substances from the previous EU chemicals regulatory frameworks (EINECS, ELINCS and the NLP-list). More information about the EC Inventory can be found here.

If the substance was not covered by the EC Inventory, ECHA attributes a list number in the same format, starting with the numbers 6, 7, 8 or 9.

The EC or list number is the primary substance identifier used by ECHA.

CAS (Chemical Abstract Service) registry number

The CAS number is the substance numerical identifier assigned by the Chemical Abstracts Service, a division of the American Chemical Society, to substances registered in the CAS registry database. A substance identified primarily by an EC or list number may be linked with more than one CAS number, or with CAS numbers that have been deleted. More information about CAS and the CAS registry can be found here.

Molecular formula

The molecular formula identifies each type of element by its chemical symbol and identifies the number of atoms of each element found in one discrete molecule of the substance. This information is only displayed if the substance is well–defined, its identity is not claimed confidential and there is sufficient information available in ECHA’s databases for ECHA’s algorithms to generate a molecular structure.

Molecular structure

The molecular structure is based on structures generated from information available in ECHA’s databases. If generated, an InChI string will also be generated and made available for searching. This information is only displayed if the substance is well-defined, its identity is not claimed confidential and there is sufficient information available in ECHA’s databases for ECHA’s algorithms to generate a molecular structure.

More help available here.