Project Details Standard InChI-based Representation of Chemical Reactions

Project No.:
Start Date:
01 November 2010
End Date:
31 March 2017


To develop a standard machine-readable, indexable and searchable representation of chemical reactions based on the IUPAC International Chemical Identifier (InChI).

> Link to InChI subcommittee


The IUPAC International Chemical Identifier (InChI) algorithm is now well established as a powerful means of denoting a well-defined chemical structure as a unique machine-readable character string, suitable for electronic data storage, searching and exchange.

The IUPAC Division VIII InChI Subcommittee is now working on widening the range of applicability of the Identifier, and with this in mind is creating a number of projects designed to facilitate various extensions. In the present case the aim is to develop an InChI-based representation of chemical reactions. The work will build upon the preliminary meeting on this subject in Berlin in May 2008 and the resulting exploratory work carried out in Summer 2009 at the Unilever Centre for Molecular Science Informatics in Cambridge UK.
Discussions will take place by e-mail and at two face-to-face (annual) meetings. Any necessary software development will be carried out by contractors appointed and paid by the InChI Trust, a non-profit entity funded by external organizations that use and benefit from the InChI algorithm.


A trial version for a reaction InChI is available as a basis for discussion on:

Sept 2015 update – A test system prepared by StructurePendium is available to the working group, and a release in 2016 is expected.

March 2017 update – Prototype versions of the RInChI have been available since 2011 (Grethe, Goodman and Allen, Journal of Cheminformatics 2013, 5, 45. DOI: 10.1186/1758-2946-5-45). The first official release (RInChI-V1.00), funded by the InChI Trust and with Gerd Blanke as lead developer, is now available for download ( This release defines the format and generates hashed representations (RInChIKeys) suitable for database and web operations. The RInChI provides a concise description of the key data in chemical processes, and facilitates the manipulation and analysis of reaction data.

The RInChI-V1.00 release is announced in Chem Int Apr 2017, p. 20;

Page last updated 26 May 2017