Project Details Handling of Inorganic compounds for InChI V2

Project No.:
Start Date:
01 March 2013
End Date:


To establish requirements and guidelines for improving the handling of inorganic compounds in the next generation of the InChI algorithm to address the shortcomings of the current algorithm.

> Link to InChI subcommittee


The IUPAC International Chemical Identifier (InChI) algorithm is now well established as a powerful means of denoting the basic chemical structure of a well-defined, small (IUPAC Division VIII InChI Subcommittee is now starting work on a complete overhaul of the InChI algorithm, i.e. the beginning of plans for a version 2 of InChI. A crucial part of this work is intended to address the known shortcomings of the current InChI algorithm pertaining to the handling (or lack thereof) of various types of inorganic compounds.

The present project is devoted to analysis of the current handling of the various types of inorganic compounds in InChI, their deficiencies, their connection with metal disconnection and protonation/deprotonation, comparison of InChI’s current algorithm with approaches published in literature and/or used in other databases and software, and putting together a list of new requirements of how an InChI V2 algorithm should handle inorganic compounds and related issues.


This project is on hold, pending receipt of proposals for InChIs for organometallic and coordination compounds (project 2009-040-2-800).

March 2019 update – This project is still on hold, as it is dependent on progress on proposals for InChIs for organometallic and coordination compounds. The latter project task group has produced an outline that will allow further investigation of InChI production for such compounds.

Last update 12 March 2019