The Commission on Isotopic Abundances and Atomic Weights is a commission under the Inorganic Division (Division II) of the International Union of Pure and Applied Chemistry (IUPAC). Founded in 1919, IUPAC is a voluntary, non-governmental, nonprofit association of 44 National Adhering Organizations representing the chemists of their countries.

The objectives of IUPAC are:
(i) to promote continuing cooperation among the chemists of the member countries,
(ii) to study topics of international importance to pure and applied chemistry that needs standardization and codification,
(iii) to cooperate with other international organizations that deal with topics of a chemical nature, and
(iv) to contribute to the advancement of pure and applied chemistry.

Purpose of the Commission
For several decades the Commission on Isotopic Abundances and Atomic Weights (CIAAW) has met biennial at or prior to the IUPAC General Assembly. CIAAW evaluates the scientific literature and publishes at regular intervals a Table of Standard Atomic Weights, a Table of Isotopic Compositions of the Elements, and a Review of Atomic Weights of the Elements. As needed, abridged Tables of Standard Atomic Weights, recommendations on reporting of isotopic data, and other reports are published. In evaluating the literature and recommending values, CIAAW follows its Technical Guidelines.

History of the Commission
The Commission on Isotopic Abundances and Atomic Weights derives from The International Committee on Atomic Weights formed in 1902 and was affiliated with IUPAC at its formation in 1919. The name of the Commission has changed during the last century and it has been know as the Committee on Chemical Elements, the Atomic Weights Committee, the Commission of Atomic Weights, and the Commission of Atomic Weights and Isotopic Abundances (CAWIA). Recognizing the increasing importance of isotopic abundances, the Commission was renamed in 2002 to the Commission on Isotopic Abundances and Atomic Weights (CIAAW).

Links of Interest
Société Française des Isotopes Stables