PubChem uses the latest IUPAC atomic mass

PubChem now uses the latest IUPAC recommendations for atomic mass and isotopic composition information. In addition, the allowed isotopes for a given element are restricted to those with a half-life of one millisecond or greater. These changes affect the molecular weight values computed for nearly all compounds in PubChem. To learn more, please read this post.
Source: PubChem News - Category: Chemistry Authors: Source Type: news