The IUPAC International Chemical Identifier (InChI) algorithm is now well established as a powerful means of denoting the chemical structure of a well-defined, small (

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 each case the aim is to define precisely the requirements for structural representation in areas of chemistry not currently handled satisfactorily by InChI, bearing in mind that these requirements are to be translated into extensions of the InChI algorithm.

Discussions will take place by e-mail and at two face-to-face (annual) meetings. Once established, the requirements will be applied to the necessary software development 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. The present project is devoted to representations of organometallic and coordination compound structures. Such structures are particularly difficult to handle because standard representations based on simple connection tables are not a good approximation to reality and different, conflicting, conventions are used by different databases. The project will examine the various types of representation in general use, and propose appropriate translations to forms that an InChI-type algorithm can handle. Test structures will be provided by Elsevier (10,000) and the US National Cancer Institute (250,000), and the members of the Editorial Board and International Advisory Board of Dalton Transactions will be consulted for advice on currently acceptable representations.