Gadolinium
Isotope | Atomic mass (Da) | Isotopic abundance (amount fraction) |
---|---|---|
152Gd | 151.919 799(8) | 0.0020(3) |
154Gd | 153.920 873(8) | 0.0218(2) |
155Gd | 154.922 630(8) | 0.1480(9) |
156Gd | 155.922 131(8) | 0.2047(3) |
157Gd | 156.923 968(8) | 0.1565(4) |
158Gd | 157.924 112(8) | 0.2484(8) |
160Gd | 159.927 062(9) | 0.2186(3) |
In 1969, the Commission recommended the atomic weight of gadolinium to be Ar(Gd) = 157.25(3) based on recent mass-spectrometric determinations. It has remained unchanged since that time.
152Gd has a very long half-life in excess of 1014 a. Within the life time of the earth, this radioactivity will not have affected the atomic weight to the precision here quoted. The "g" notation arises from the presence of naturally occurring fission products found in fossil reactors at Gabon, south-west Africa.
© IUPAC 2003
CIAAW