Project Details Evaluated published isotope ratio data (2007-2009)

Project No.:
Start Date:
01 January 2008
End Date:
13 December 2010


Evaluate isotope ratio publications between 2007 and early 2009, to determine “best isotope ratio measurements” for compilation and publication in a 2009 TICE, recommend “new” standard atomic weights, and publish “Atomic Weights of the Elements 2009” in Pure and Applied Chemistry, which will also include a table of relative atomic masses.

Remark: project 2005-027-1-200 covered data 2005-2007


The aim of the task group is to evaluate isotope ratio publications between early-2007 and early 2009. The evaluated data will be incorporated into the CIAAW* Table of Isotopic Composition of the elements (TICE) and Table of Standard Atomic Weights.

> *see CIAAW activities

The Subcommittee on Isotopic Abundance Measurements (SIAM) in CIAAW recognizes that there are a number of elements that need particular attention and for which significant publications are expected. These include Cr and Zn.

In July 2009, task group members will convene in Glasgow, prior to the IUPAC General Assembly, to evaluate recently published isotope ratios and resulting atomic-weights reports face-to-face. Detailed discussions and calculations will be carried out on any chemical element for which new isotope ratio information exists. Particular attention will be paid to authors’ evaluations of uncertainty, the selection of materials for analysis, and the variability of isotope ratio measurements in these materials. In a second meeting in July 2009, task group members will present their recommendations for adoption of best isotopic ratios and new standard atomic weights to the Commission on Isotopic Abundances and Atomic Weights at the General Assembly in Glasgow.

It is anticipated that new standard atomic weights will be recommended, and a press release announcing these recommendations will be provided to the IUPAC Secretariat. Subsequently, a publication titled “Atomic Weights of the Elements 2009” will be prepared for Pure and Applied Chemistry. Subsequently, publication in J. Phys. Chem. Ref. Data is anticipated.


> December 2010 – Project completed – IUPAC Technical report titled ‘Atomic weights of the elements 2009’ is published online 2010-12-12, doi:10.1351/PAC-REP-10-09-14; PAC 2011, Vol. 83, No. 2, pp. 359-396

> see also Chem Int preprint titled ‘Atomic Weights—No Longer Constants of Nature

last modified 20110321