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.

The Trust will be holding an InChI Symposium ahead of the ACS National Meeting in San Diego, on 23-24 August 2019. The event will include a mix of themed talks on use cases and working breakout sessions. Short talks around use cases especially welcome, so please indicate in the event sign-up if you would like to be a speaker.  Register for the symposium

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Working groups status:

InChI releasev1.05 now released, available from the downoad area. 1.06 bugfix in preparation
Positional isomers and variabilityScientific proposals under review
Reaction InChIv1.00 of the RInChI is available from the download area; further extensions being discussed
OrganometallicsExploring a new InChI layer for organometallic and coordination compounds
InChI for large moleculesScientific proposals under review
TautomersPilot site: https://cactus.nci.nih.gov/tautomerizer/
Mixture compositionFinalising provisional spec of the notation, a pilot implementation and test case, and description of several target use cases
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.