Project Details:

Preferred IUPAC Names (PINs) for Inorganic Compounds

Project No.:2006-038-1-800
Start date:2007-01-01
End date:0000-00-00
Division:Chemical Nomenclature and Structure Representation Division
To develop rules for choosing the Preferred IUPAC Names (PIN) forinorganic compounds, including coordination compounds, organometalliccompounds, and compounds that either do not contain carbon, or docontain at least one element from groups 1-12. These rules shouldresult in names that are suitable for use in legal and regulatorydocumentation.
The PIN concept has been developed in response to the difficulties that users of nomenclature strike when there is more that one systematic way of naming a compound. This issue is particularly problematic in legal and regulatory applications, where confusion over names could have major health and safety, legal, or financial implications.

Rules for choosing PINs for organic molecules have been developed as a major goal of the project for the revision of the Blue Book (project 2001-043-1-800). That project is nearing completion, and the resulting manuscript is in the IUPAC review process. It is obvious that PINs must also be available for inorganic compounds, but the methods that are typically used to name such compounds are different from those used for organic compounds, and consequently new rules will have to be developed.

A number of critical issues will have to be addressed; these include:

  • choice of central atom(s), particularly in polynuclear species;
  • clear definition of grammatical rules for the placement of k/h symbols in complicated ligand names;
  • selection of retained names, particularly for oxo-acids.

Once these issues have been addressed, the proposals that are developed will be submitted to the IUPAC review process. Further documents will then be prepared that provide detailed guidance for selecting PINs for particular classes of compounds (coordination compounds, organometallic compounds, main group compounds).


Jan 2012 update: A draft document has been prepared that expands and better delineates the grammar required for use of the kappa convention for describing coordination. The implications for more complicated systems are currently being discussed before the document is sent out for review.

After considerable discussion, the task group has a clearer idea of the extent of coverage of this project, particularly regarding the division of responsibility between this project and that on revision of the Blue Book (project 2001-043-1-800). Significant progress has been made on choice of central atoms.