||I U P A C
The IUPAC International Chemical Identifier
The IUPAC International Chemical Identifier (InChITM)
is a non-proprietary identifier for chemical substances that can be
used in printed and electronic data sources thus enabling easier linking
of diverse data compilations.* It was developed
under IUPAC Project
2000-025-1-800 during the period 2000-2004. Details of the project
and the history of its progress are available from the project
> A list of software
providers, and journal
publishers incorporating InChI in their products is
The InChITM program version 1.04 is free software developed under the auspices of the International Union of Pure and Applied Chemistry (IUPAC) and the InChI Trust. You can redistribute it and/or modify it under the terms of the IUPAC-InChI Trust License <http://www.inchi-trust.org/sites/default/files/inchi-1.04/LICENCE.pdf>. This is a more permissive version of the GNU Lesser General Public License version 2.1 <http://www.opensource.org/licenses/lgpl-2.1.php> that was applied to previous versions of the software.
The source code and associated software and documentation can be
downloaded from HERE.
1.01 Software Release, August 2006
> InChI 1.02beta Software
Release, September 2007
> InChI Software Version 1.02 – final, implemented for Standard InChI/InChIKey, January 2009
> InChI version 1 (software version 1.03 for Standard and Non-Standard InChI/InChIKey), June 2010
> InChI version 1 (software version 1.04 for Standard and Non-Standard InChI/InChIKey), September 2011
[access Software Downloads on www.inchi-trust.org]
IUPAC continues to maintain oversight of InChI development;
only systems compliant with the validation protocol (first issued
with software release 1.01) are authorised to use the InChI designation.
IUPAC welcomes proposals for enhancements. To enable and encourage
development of InChI facilities and applications in an Open Source
context, a project to encompass this work has been registered with
SourceForge.net (see http://sourceforge.net/projects/inchi),
and people wishing to participate should register via the SourceForge
web page <https://lists.sourceforge.net/lists/listinfo/inchi-discuss>.
> News articles on the Identifier are listed here
> Journal articles that use InChI are listed here
The following websites provide the facility to generate
This service works as a resolver for different chemical structure identifiers and allows the conversion of a given structure identifier into another representation or structure identifier.
Services provide methods to manipulate InChI Strings and InChIKeys,
including conversion to and from the MOLfile format, checking validity
of the InChI identifiers, searching ChemSpider using InChI inputs
PubChem Server Side Structure Editor v1.8 includes a facility for
generating InChIs as you draw the structure.
For a video about InChI, see Stephen Heller
and Stephen Stein at Google Tech Talks on 2 Nov 2006 (1
hr 7 min 18 sec; Flash 7 or higher to watch this video)
For presentation slides only, see here.
Abstract : The central token of information in Chemistry is
a chemical substance, an entity that can often be represented as a
well-defined chemical structure. With InChI we have a means of representing
this entity as a unique string of characters, which is otherwise represented
by various of 2-D and 3-D chemical drawings, 'connection tables' and
synonyms. InChI therefore represents a discrete physical entity, to
which is associated as array of chemical properties and data...
Also of interest, see Google Tech Talks of 13 Sept 2006
by Peter Murray-Rust, titled 'The Semantic Chemical Web: GoogleInChI
and other Mashups' (54 min 48 sec)
* Stephen E. Stein, Stephen R. Heller,
and Dmitrii Tchekhovskoi, An
Open Standard for Chemical Structure Representation: The IUPAC Chemical
Identifier, in Proceedings of the 2003 International Chemical
Information Conference (Nimes), Infonortics, pp. 131-143.
Promotion and extension
Page last modified 12 October 2011.
Copyright ©1997- 2011 International Union of Pure and Applied Chemistry.
Questions or comments about IUPAC, please contact, the Secretariat.
Questions regarding the website, please contact Web