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 Inorganic Chemistry (II)

Commission on Atomic Weights and
Isotopic Abundances (II.1)


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Summary of Minutes of Commission Meeting at IUPAC General Assembly, Brisbane, Australia, 30 June-2 July 2001

The Commission on Atomic Weights and Isotopic Abundances (II.1) met for three days of discussions under the chairmanship of Prof. Ludolf Schultz during the 41st IUPAC General Assembly in Brisbane. As well as the normal scientific work of Commission II.1, considerable discussion also took place on the continued existence of the Commission and the operations of its subcommittees under the project-driven post-2001 IUPAC.

The standard atomic weights of four chemical elements have been changed, based on new determinations of isotopic abundances and reviews of previous isotopic abundances. The standard atomic weight of zinc was changed from 65.39(2) to 65.409(4), of krypton from 83.80(1) to 83.798(2), of molybdenum from 95.94(1) to 95.94(2), and of dysprosium from 162.50(3) to 162.500(1). These changes in atomic weights will be published in a new Table of Standard Atomic Weights 2001, which will be submitted to Pure and Applied Chemistry (PAC) by the end of 2001.

The Commission also continued its review of publications on the variation in the natural isotopic abundances in both terrestrial and extraterrestrial materials. The groundbreaking work of the Subcommittee for Natural Isotope Fractionation (SNIF) has produced a valuable isotopic composition database for use by the other subcommittees in determinations of the uncertainties of atomic weights and culminated in a major manuscript currently being finalized for publication in PAC.

In the future, the work performed by the SNIF will be undertaken by the Subcommittee for Isotopic Abundance Measurements. The element-by-element review 2000 project, coordinated and edited over the last few years by Prof. John de Laeter, has resulted in a major document of special historical and scientific interest. This report is also now being prepared for publication in PAC.

The future of the Commission and its scientific work was discussed in a joint session with the Commission on Isotopic Specific Measurements as Traceable References (II.4). The joint session supported the proposal before the Bureau and Council to establish a Commission on Isotopic Abundances and Atomic Weights. It was recommended that the following subcommittees be formed by the Division Committee: Subcommittee for Isotopic Abundance Measurements (SIAM), Subcommittee for Extraterrestrial Isotopic Ratios (SETIR), and Subcommittee for Applications of Isotopic Specific Measurements (SAISR). A number of projects were prepared by the subcommittees for presentation to the Division Committee.

On a very sad note, the Commission learned of the most unexpected death of a long-standing Titular Member, Dr. Gregory Ramendik, in the days immediately following the Commission meeting. Gregory’s efforts on behalf of the Commission will be long remembered, and our deepest sympathy and condolences are extended to his family and colleagues.

Robert D. Loss
Secretary, IUPAC Commission on Atomic Weights and Isotopic Abundances II.1

> Download full text of the minutes of the meeting (pdf file - xxkb)

> Summary published in Chem. Int. 23(6), 2001

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