The IUPAC International Chemical Identifier (InChI) is a non-proprietary identifier for chemical substances that can be used in printed and electronic data sources. It is derived solely from a structural representation of that substance, such that a single compound always yields the same identifier.

Prefix

inchi

Keywords

centrally registered identifier chemical entity chemical structure image cheminformatics chemistry molecular entity structure

Links

Homepage

Publications

2021 InChI version 1.06: now more than 99.99% reliable

2015 InChI, the IUPAC International Chemical Identifier

2015 Many InChIs and quite some feat

2024 InChI isotopologue and isotopomer specifications

Pattern for Local Unique Identifiers

Local identifiers in InChI should match this regular expression:
^InChI\=1S?\/[A-Za-z0-9\.]+(\+[0-9]+)?(\/[cnpqbtmsih][A-Za-z0-9\-\+\(\)\,\/\?\;\.]+)*$

Example Local Unique Identifier

InChI=1S/C2H6O/c1-2-3/h3H,2H2,1H3   Resolve

Pattern for CURIES

Compact URIs (CURIEs) constructed from InChI should match this regular expression:
^inchi:InChI\=1S?\/[A-Za-z0-9\.]+(\+[0-9]+)?(\/[cnpqbtmsih][A-Za-z0-9\-\+\(\)\,\/\?\;\.]+)*$

Example CURIE

inchi:InChI=1S/C2H6O/c1-2-3/h3H,2H2,1H3

Contact

Stephen R. Heller   0000-0002-5538-8482

A summary of the relations in the Bioregistry schema can be found here.

In Collection (1)

Synapse.org external links

Mappings from records in Bioregistry to external registries comprises the metaregistry. This resource has 6 mappings to external registries with 4 unique external prefixes.

A provider turns a local unique identifiers from a resource into a URI. Many providers are also resolvable as URLs (i.e., they can be used in a web browser).

The local unique identifier InChI=1S/C2H6O/c1-2-3/h3H,2H2,1H3 is used to demonstrate the providers available for InChI. Some providers may use a different example, which is displayed in the table below. A guide for curating additional providers can be found here.

Additional providers curated in the Bioregistry are listed here. These are typically inherited from Identifiers.org or Prefix Commons, and need extra curation.