Average atomic weight: 91.224(2) u
| Isotope | Fraction | Atomic weight/u |
| 90 | 0.5145(40) | 89.9046977(20) |
| 91 | 0.1122(5) | 90.9056396(20) |
| 92 | 0.1715(8) | 91.9050347(20) |
| 94 | 0.1738(28) | 93.9063108(20) |
| 96 | 0.0280(9) | 95.9082714(21) |
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)
