(this element does not have any stable isotopes)
Atomic weight of the most stable isotope: 223.0197360(25) u
| Isotope | Atomic weight/u | Half-life |
| 198 | [198] | 15 ms 3 |
| 199 | 199.007259(45) | 4.5 ms +31-13 |
| 200 | 200.006586(63) | 49 ms 4 |
| 201 | 201.003867(77) | 62 ms 5 |
| 202 | 202.003320(55) | 0.372 s 12 |
| 203 | 203.0009407(67) | 0.55 s 1 |
| 204 | 204.000652(26) | 1.8 s 3 |
| 205 | 204.9985939(84) | 3.97 s 4 |
| 206 | 205.998666(30) | ≈ 16 s |
| 207 | 206.996946(19) | 14.8 s 1 |
| 208 | 207.997138(12) | 59.1 s 3 |
| 209 | 208.995955(16) | 50.5 s 7 |
| 210 | 209.996422(16) | 3.18 m 6 |
| 211 | 210.995556(13) | 3.10 m 2 |
| 212 | 211.9962257(94) | 20.0 m 6 |
| 213 | 212.9961860(55) | 34.82 s 14 |
| 214 | 213.9989713(93) | 5.0 ms 5 |
| 219 | 219.0092524(76) | 20 ms 2 |
| 220 | 220.0123277(44) | 27.4 s 3 |
| 221 | 221.0142552(54) | 286.1 s 10 |
| 222 | 222.017552(23) | 14.2 m 3 |
| 223 | 223.0197360(25) | 22.00 m 7 |
| 224 | 224.023398(14) | 3.33 m 10 |
| 225 | 225.025573(13) | 3.95 m 14 |
| 226 | 226.029566(13) | 49 s 1 |
| 227 | 227.031869(14) | 2.47 m 3 |
| 228 | 228.035823(14) | 38 s 1 |
| 229 | 229.038298(15) | 50.2 s 20 |
| 230 | 230.042416(17) | 19.1 s 5 |
| 231 | 231.045158(27) | 17.6 s 6 |
| 232 | 232.04937(17) | 5.5 s 6 |
| 233 | 233.05264(32) | 0.9 s 1 |
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)
