(this element does not have any stable isotopes)
Atomic weight of the most stable isotope: 263.11249(20) u
| Isotope | Atomic weight/u | Half-life |
| 255 | 255.10127(12) | 1.68 s 9 |
| 256 | 256.101152(19) | 6.67 ms 10 |
| 257 | 257.102918(12) | 4.4 s +6-5 |
| 258 | 258.103428(34) | 14.7 ms +12-1 |
| 259 | 259.105596(78) | 2.4 s 4 |
| 260 | 260.10644(22) | 21 ms 1 |
| 261 | 261.108773(54) | 68 s 3 |
| 262 | 262.10992(24) | 2.3 s 4 |
| 263 | 263.11249(20) | 10 m 2 |
| 265 | 265.11668(39) | 1.0 m +12-3 |
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)
