How we work
Work to extend the InChI standard is governed by IUPAC and the InChI Trust, via the Scientific Advisory Group and the Technical Implementation Steering Group (for terms of reference etc, see here).
InChI Project Groups
InChI Project Groups are set up to specify new extensions to the algorithm or applications of the InChI to address other scientific use cases.
For extensions of the standard, we currently have groups looking at organics/inorganics, extended stereochemistry, tautomers, isotopologues, large molecules and Markush.
Applications of the InChI algorithm or approach are being explored or have been implemented for nanomaterials, mixtures, reactions, QR codes, InChI resolver, and educational materials.
Here’s a recent slide desk which summarises InChI and much of the work from the project groups (Aug 2024): Dynamic InChI: canonical, unique and on-the-fly
Extension project groups
Organics and Inorganics
Organometallics/Inorganics Project Group Chair: Sonja Herres-Pawlis, Gerd Blanke
Project Group Members: Sonja Herres-Pawlis; Gerd Blanke;
Possible other members: Alex Clark; Andrey Yerin; Clare Tovee; Colin Batchelor; Dmitrii Tchekhovskoi; Evan Bolton; Ian Bruno; Jane Frommer; Jonathan Goodman; Richard Hartshorn; Steve Hellers; Thomas Doerner; Ulrich Schatzschneider; Yulia Borodina
The Working Group is discussing how a proposed representation of organometallic and inorganic compounds within InChI can be implemented. A prototype for molecular inorganics is available through the Web Demo
See:
Gerd Blanke, Jan Brammer, Djordje Baljozovic, Nauman Ullah Khan, Frank Lange, Felix Bänsch, Clare A. Tovee, Ulrich Schatzschneider, Richard M. Hartshorn and Sonja Herres-Pawlis
Making the InChI FAIR and sustainable while moving to inorganics,
Faraday Discuss., 2025, 256, 503-519
DOI: https://doi.org/10.1039/D4FD00145A
Extended Stereochemistry
Project Group Chair: Andrey Yerin
Project Group Members: Andrey Yerin; Gerd Blanke; Burt Leland; Jürgen Kammerer; Clare Tovee; Yulia Borodina; Jane Frommer; Nicki Davis; Per-Ola Norrby; Jonathan M Goodman
The project is making progress and is investigating possible solutions for further consideration. These include enhanced stereo marks; tropisomers; longer allenes; etc.
Tautomers
Project Group Chair: Marc C. Nicklaus
Project Group Members: Gerd Blanke; Evan Bolton; Alex M. Clark; Bret Daniel; Devendra Dhaked; Laura Guasch; Wolf; Dietrich Ihlenfeldt; Gregory Landrum; John W. Mayfield; Hitesh Patel; Roger Sayle; Dmitrii Tchekhovskoi
This group is studying how to extend tautomer handling in InChI. Of the 90 tautomeric transforms that were identified, six could be incorporated in an experimental version of the InChI code (based on InChI version 1.06). See the report “Tautomers in InChI” presented at the March 2021 NIH InChI Workshop.
Also see:
Toward a Comprehensive Treatment of Tautomerism in Chemoinformatics Including in InChI V2, Devendra K. Dhaked, Wolf-Dietrich Ihlenfeldt, Hitesh Patel, Victorien Delannée, and Marc C. Nicklaus, Journal of Chemical Information and Modeling 2020 60 (3), 1253-1275 DOI: 10.1021/acs.jcim.9b01080
Isotopologues
Project Group Chair: Hunter Moseley
Project Group Members: Hunter Moseley; Philippe Rocca-Serra; Reza Salek; Masanori Arita; Emma Schymanski
Develop enhanced specifications within the regular InChI standard for representing isotopologues and isotopomers. More specifically, augment the isotopic layer specifications of the regular InChI standard so that specific isotopologues, isotopomers, partial isotopomers, and isotopologue fragments can be represented by a single InChI string and used to identify isotope-informative analytical features.
See:
Moseley, H.N.B., Rocca-Serra, P., Salek, R.M. et al. InChI isotopologue and isotopomer specifications. J Cheminform 16, 54 (2024). https://doi.org/10.1186/s13321-024-00847-8
Markush
Project Group Chair: Jonathan Goodman
Project group: Gerd Blanke, István Öri, Anthony Baston
Summary:
- A framework is been defined, based on InChI v1.06
- Canonicalization and stereo differentiation under examination
- Creating VInChI: provide a list of InChI and VInChI
- Creating MarkInChI: currently hand-crafted by artisans
Large Molecules
Project Group Chair: Evan Bolton
Project Group Members: Keith Taylor; Roger Sayle; John May; Noel O’Boyle; Daniel Lowe; Claire Bellamy; Anna Gaulton; Leah McEwen
A presentation titled ‘Progress towards “Large Molecule” support within InChI’ was given at a recent (March 2021) NIH Workshop on InChI by Evan Bolton.
Application project groups
Nanomaterials
Project Group Chair: Iseult Lynch
Project Group Members: Iseult Lynch; Antreas Afantitis; Thomas Exner; Fred Klaessig; Nikolay Kochev; Martin Himly; Gergana Tancheva; Jaleesia Amos; Mark Wiesner; Egon Willighagen; Alex Clarke; Gerd Blanke; Jonathan Goodman; Vladimir Lobaskin; John Rumble; Georgia Melagraki; Tassos Papadiamantsis; Harry Sarimveis; Dieter Maier; Effie Marcoulaki; Kostas Blekos; Steve Heller; Clyde Daly; Michael Schwartz; Nikki Davis; Diego Martinez; Nikolaos Nikoloudakis; Ioannis Xiarchos
This project proposes to identify a specific nanomaterial/nanoform through an extension of the IUPAC InChI called NInChI. The approach is to encode information
This project proposes to identify a specific nanomaterial/nanoform through an extension of the IUPAC InChI called NInChI. The approach is to encode information such as composition, size, shape, surface chemistry, etc. As nanomaterials are particulates, there is an intimate relationship between the core and surface compositions that challenges traditional naming conventions, thereby limiting information exchange among scientists and computational modelers across academia, industry and regulatory agencies. Leveraging best practices with other InChI working groups e.g. Mixture InChI, Reaction InChI & Polymer InChI are planned.
See:
Lynch, I.; Afantitis, A.; Exner, T.; Himly, M.; Lobaskin, V.; Doganis, P.; Maier, D.; Sanabria, N.; Papadiamantis, A.G.; Rybinska-Fryca, A.; et al. Can an InChI for Nano Address the Need for a Simplified Representation of Complex Nanomaterials across Experimental and Nanoinformatics Studies? Nanomaterials 2020, 10, 2493. https://doi.org/10.3390/nano10122493
Mixtures
Project Group Chair: Leah McEwen
Project group: Alex Clark, Antony Davies, John Duffus, Chris Jakober, Jon LaRue, Gerd Blank, Richard Hartshorn, Andrey Yerin
The IUPAC MInChI project defines a method to apply the IUPAC InChI identifier to describe what is definitively known about the chemical composition of a given mixed substance, generating an unambiguous machine-readable linear notation for mixed substances of uniform properties that can resolve to unique components. These requirements and guidelines allow for the generation of a unique computer-readable MInChI for chemical mixtures that can be used in chemical stock inventories and information systems based on the InChI standard.
See:
Capturing mixture composition: an open machine-readable format for representing mixed substances.
Clark, Alex M.; McEwen, Leah R.; Gedeck, Peter; Bunin, Barry A.
J Cheminform 11 33 (2019).
DOI: https://www.doi.org/10.1186/s13321-019-0357-4
Reactions
Project Group Chair: Gerd Blanke
Project group: Gerd Blanke, Günter Grethe, Gudrun Gygli, Hans Kraut, István Öri, Jan Holst Jensen, Jonathan Goodman, Nicki Davis
A standard machine-readable, indexable and searchable representation of chemical reactions based on the IUPAC International Chemical Identifier (InChI).
Version 1.0 of the Reaction InChI is the current version, with RInChI 1.1 in test as of end-2023.
See InChI Downloads and:
International chemical identifier for reactions (RInChI).
Grethe, Guenter; Blanke, Gerd; Kraut, Hans; Goodman, Jonathan M.
J Cheminform 10 22 (2018).
DOI: 10.1186/s13321-018-0277-8
Education (OER)
Project Group Chair: Robert E. Belford
Project Group Members: Bob Belford; Nathan Brown; Ehren Bucholtz; Jordi Cuadros; Tanya Gupta; Tina Qin; Vincent Scalfani; Martin Walker; Steven Wathen; Andrew Cornell
The primary mission of the OER task group is to bring about a greater awareness of InChI in the education community, while also facilitating its use and adoption across other communities. There are three major facets to this endeavor; creating original educational material, and creating resources that allow educators and scientists to share material with others, with the latter being the mission of the OER website, and general outreach (running workshops, symposia, giving talks, posters, etc).
See:
IUPAC International Chemical Identifier (InChI)-related education and training materials through InChI Open Education Resource (OER): Cornell, Andrew P., Kim, Sunghwan, Cuadros, Jordi, Bucholtz, Ehren C., Pence, Harry E., Potenzone, Rudy and Belford, Robert E.
Chemistry Teacher International, 2024.
https://doi.org/10.1515/cti-2023-0009
QR Codes
Project Group Chairs: Jeremy Frey and Richard Hartshorn
Project Group Members: Jeremy Frey; Richard Hartshorn; Leah McEwen
A proof-of-principle implementation was made available: www-rinchi.ch.cam.ac.uk/qrinchi.
A revised draft of the InChI QR code specification document, formulated as an IUPAC Recommendation, was prepared and sent out for approval. The recommendation was then revised and submitted to PAC where it is currently under review.
Resolver
Project Group Chair: Markus Sitzmann
Is it possible to recalculate the InChI out of an InChIKey? No! The InChIKey is the hashed representation of its InChI. The hashing makes it impossible to go backwards from the InChIKey to the original InChI. To find a solution the “Resolver Protocol” project was started.
The InChI Resolver Protocol is a common API protocol which allows any InChI Resolver instance to be findable and browsable for an (automated) client system in a systematic, predefined manner. It will also allow for the implementation of a network of federated InChI Resolvers
Benefits:
(long-term) an autonomous client can find and collect information based in InChI web resources providing data & information based on InChI become findable & interlinked on the web their content is accessible in a generic way
