Atomic Weights of the Elements 1979 [dataset]

N. E. Holden
2016 IUPAC Standards Online   unpublished
The biennial review of atomic weight determinations and other cognate data has resulted in the following changes in recommended values (1975 values in parentheses): V 50.9415 (50.9414*); Lu 174.967* (174.97). These values are considered to be reliable to ±1 in the last digit or ±3 when followed by an asterisk (*) and are incorporated in the full Table of Atomic Weights of the Elements 1977. Atomic mass numbers were added for elements 104 to 106. These elements are desigmated by the names and
more » ... by the names and symbols provisionally suggested by IUPAC: 261 Unq; 262 Unp; 263 Unh. The Report outlines various problems which arise from the present imprecise definition of "atomic weight (relative atomic mass)" and has made a proposal to overcome the difficulties. The importance of having informative labels on commercially available chemicals is emphasized, particularly in order to warn or reassure users of the presence or absence of materials containing elements with unusual atomic weights due to the enrichment or depletion of isotopes. The Report includes a complete review of the natural isotopic composition of the elements and also tabulates the Relative Atomic Masses for Selected Radioisotopes.
doi:10.1515/iupac.52.0023 fatcat:7y43oxc3bnde3cb5fdahbl5y2y