InChI and InChIKeys for chemical structures

The InChI Trust is a nonprofit charity which works to develop and promote the use of the IUPAC InChI open-source chemical structure representation algorithm.

The InChI with its associated InChIKey was developed as a non-proprietary international standard to represent chemical structures and has just celebrated its tenth anniversary. The Trust aims to develop and improve on the current InChI standard, further enabling the interlinking of chemistry and chemical structures on the web.


Signup for our newsletter


Working groups status:

InChI releasev1.05 now released, available from the downoad area
Positional isomersWorking group to be set up
InChI ResolverDefinition in progress, led by Markus Sitzmann
Reaction InChIv1.00 of the RInChI is available from the downoad area
Markush InChIProposed solution exists. Awaiting funding from interested parties
Electronic statesDraft plans developed by Don Burgess
OrganometallicsWorking group close to final report, led by Colin Batchelor
InorganicsWill review needs following Organometallics implementation
InChI for large moleculesWorking group led by Keith Taylor; report on first meeting available
TautomersWorking group set up, led by Marc Nicklaus
Mixture compositionStarted Jul 2016
Support of simple polymersReleased in InChI v1.05 - now available

Watch our set of videos to find out more about the InChI and why it’s so cool.

What on Earth is InChI?

This video introduces the InChI standard to represent chemical structures.

The Googlable InChIKey

An InChIKey enables chemical structures to be uniquely identified on the web.

The Birth of the InChI

This video describes the background to the development of the InChI standard.

InChI and the Islands

The InChI standard – the International Chemical Identifier – enables the linking of information.