page_title: Commission on Isotopic Abundances and Atomic Weights
section_title: Notable members
hierarchical_section_title: Commission on Isotopic Abundances and Atomic Weights / Notable members
caption_attribution_description: Photograph of Harvard scientist Theodore Richards from about 1905, Harold Hartley, Theodore William Richards Memorial Lecture
context_page_description: The Commission on Isotopic Abundances and Atomic Weights is an international scientific committee of the International Union of Pure and Applied Chemistry under its Division of Inorganic Chemistry. Since 1899, it is entrusted with periodic critical evaluation of atomic weights of chemical elements and other cognate data, such as the isotopic composition of elements. The biennial CIAAW Standard Atomic Weights are accepted as the authoritative source in science and appear worldwide on the periodic table wall charts.
  The use of CIAAW Standard Atomic Weights is also required legally, for example, in calculation of calorific value of natural gas, or in gravimetric preparation of primary reference standards in gas analysis. In addition, until 2019 the definition of kelvin, the SI unit for thermodynamic temperature, made direct reference to the isotopic composition of oxygen and hydrogen as recommended by CIAAW. The latest CIAAW report was published in February 2016. After 20 May 2019 a new definition for kelvin came into force based on the Boltzmann constant.
context_section_description: Since its establishment, many notable chemists have been members of the Commission. Notably, eight Nobel laureates have served in the Commission: Henri Moissan (1903-1907), Wilhelm Ostwald (1906-1916), Francis William Aston, Frederick Soddy, Theodore William Richards, Niels Bohr, Otto Hahn and Marie Curie.
  Richards was awarded the 1914 Nobel Prize in Chemistry "in recognition of his accurate determinations of the atomic weight of a large number of chemical elements" while he was a member of the Commission. Likewise, Francis Aston was a member of the Commission when he was awarded the 1922 Nobel Prize in Chemistry for his work on isotope measurements. Incidentally, the 1925 Atomic Weights report was signed by three Nobel laureates.
  Among other notable scientists who have served on the Commission were Georges Urbain (discoverer of lutetium, though priority was disputed with Carl Auer von Welsbach), André-Louis Debierne (discoverer of actinium, though priority has been disputed with Friedrich Oskar Giesel), Marguerite Perey (discoverer of francium), Georgy Flyorov (namesake of the element flerovium), Robert Whytlaw-Gray (first isolated radon), and Arne Ölander (Secretary and Member of the Nobel Committee for Chemistry).
caption: The Harvard chemist Theodore W. Richards, a member of the International Atomic Weights Commission, was awarded the 1914 Nobel Prize in Chemistry for his work on atomic weight determination
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