Average atomic weight: 157.25(3) u
| Isotope | Fraction | Atomic weight/u |
| 152 | 0.0020(1) | 151.9197995(18) |
| 154 | 0.0218(3) | 153.9208741(17) |
| 155 | 0.1480(12) | 154.9226305(17) |
| 156 | 0.2047(9) | 155.9221312(17) |
| 157 | 0.1565(2) | 156.9239686(17) |
| 158 | 0.2484(7) | 157.9241123(17) |
| 160 | 0.2186(19) | 159.9270624(18) |
Atomic weights and isotopic compositions were obtained from NIST Database 144
The Atomic Line List does not contain any data for this element
(Atomic Line List v3.00b5)
