Project Details IUPAC/IUPAP Joint Working Group to Examine the 1991 Criteria used to Verify Claims for the Discovery of New Elements

Project No.:
Start Date:
01 June 2017
End Date:
04 August 2020


Over twenty-five years have elapsed since the criteria* that are currently used to verify claims for the discovery of a new element were set down. Given the fact that technology and verification methods have changed and improved in the last two decades, it is justified to ask the question if the criteria are still valid. The recent completion of the naming of the one-hundred and eighteen elements in the first seven periods of the Periodic Table of the elements provides a natural opportunity for a necessary expert review of these criteria in the light of the experimental and theoretical advances in the field. It is proposed to set up a project for an IUPAC/IUPAP Joint Working Group (JWG) to examine and update these criteria.

*Wapstra et al “Criteria that must be satisfied for the discovery of a new chemical element to be recognized”, Pure Appl. Chem., Vol. 63, No. 6, pp. 879-886 (1991);


This JWG is set up for the specific task of reviewing and, if necessary, updating the criteria for validation of discoveries of new elements from 1991. This JWG is distinct from the IUPAC/IUPAP Joint Working Parties (JWP) which has and which – later – will evaluate actual claims of discovered new elements. Should the present JWG recommend any changes to these criteria, it will include in its report a recommendation on whether a JWP needs to be appointed to re-examine priorities assigned to any of the recently discovered elements based on these new criteria.


May 2018 – A draft of the technical report has been prepared and is under review.

The first meeting of the JWG was in May 2017 and a report prepared by Sigurd Hofmann, Sergey N. Dmitriev, Claes Fahlander, Jacklyn M. Gates, James B. Roberto and Hideyuki Sakai, was submitted to the Presidents of IUPAC and IUPAP May 25, 2018.

Foundation meeting of the ‘Joint Working Group’, JWG, in Egelsbach near Darmstadt, Germany, 20-22 May 2017. Left to right: Sigurd Hofmann (Chair), Sergey Dmitriev, Jacklyn Gates, Natalia Tarasova (2017 President of IUPAC) proudly keeping the Chart of Nuclei in her hands, Bruce McKellar (2017 President of IUPAP), James Roberto, Hideyuki Sakai (Vice Chair), and Claes Fahlander, respectfully holding the Periodic Table of the Elements.


Nov 2018 update – A IUPAC/IUPAP Provisional Report titled “On the discovery of new elements” has been prepared and is available for comments till 31 March 2019 – see details. See also News item released 14 Nov 2018.


Sept 2020 update – The IUPAC/IUPAP Report titled “On the discovery of new elements” has been finalized and published in PAC 92(9), 1387-1446 (AOP 4 Aug 2020);


Project completed

Page last updated 23 Sep 2020