(this element does not have any stable isotopes)
Atomic weight of the most stable isotope: 227.0277523(25) u
| Isotope | Atomic weight/u | Half-life |
| 224 | 224.0217232(45) | 2.78 h 17 |
| 225 | 225.0232300(53) | 9.920 d 3 |
| 226 | 226.0260984(36) | 29.37 h 12 |
| 227 | 227.0277523(25) | 21.772 y 3 |
| 228 | 228.0310215(27) | 6.15 h 2 |
| 229 | 229.032956(13) | 62.7 m 5 |
Units: y = year, d = day, h = hour, m = minute, s = second, ms = millisecond, µs = microsecond.
Numbers in italics are uncertainties with the same unit as the last digit of the half-life.
Atomic weights were obtained from NIST Database 144
The half-life of radioactive isotopes was obtained from the Nuclear Wallet Cards
The Atomic Line List does not contain any data for this element
(Atomic Line List v3.00b5)
