(this element does not have any stable isotopes)
Atomic weight of the most stable isotope: 209.9871479(83) u
| Isotope | Atomic weight/u | Half-life |
| 194 | 193.999236(29) | 310 ms 8 |
| 195 | 194.9962685(98) | 290 ms 20 |
| 196 | 195.995800(33) | 0.388 s 7 |
| 197 | 196.993189(55) | 0.388 s 6 |
| 198 | 197.992784(54) | 4.2 s 2 |
| 199 | 198.9905277(58) | 6.92 s 13 |
| 200 | 199.990351(26) | 43 s 1 |
| 201 | 200.9884171(88) | 85.2 s 16 |
| 202 | 201.988630(30) | 184 s 1 |
| 203 | 202.986943(11) | 7.4 m 2 |
| 204 | 203.987251(24) | 9.12 m 11 |
| 205 | 204.986076(16) | 26.9 m 8 |
| 206 | 205.986657(16) | 30.6 m 8 |
| 207 | 206.985800(13) | 1.81 h 3 |
| 208 | 207.9866133(96) | 1.63 h 3 |
| 209 | 208.9861702(55) | 5.42 h 5 |
| 210 | 209.9871479(83) | 8.1 h 4 |
| 211 | 210.9874966(30) | 7.214 h 7 |
| 212 | 211.9907377(26) | 0.314 s 2 |
| 217 | 217.0047192(55) | 32.3 ms 4 |
| 218 | 218.008695(12) | 1.5 s 3 |
| 219 | 219.0111618(42) | 56 s 3 |
| 220 | 220.015433(15) | 3.71 m 4 |
| 221 | 221.018017(15) | 2.3 m 2 |
| 222 | 222.022494(17) | 54 s 10 |
| 223 | 223.025151(15) | 50 s 7 |
| 224 | 224.029749(24) | 1.3 m +23-43 |
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)
