Most of the isotope data on this site has been obtained from the National Nuclear Data Center.
Naturally Occurring Isotopes
| Mass Number | Natural Abundance | Half-life |
| 209 | 100% | 1.9×10+19 years |
Known Isotopes
| Mass Number | Half-life | Decay Mode | Branching Percentage |
| 184 | 13 milliseconds | Alpha Decay | 100.00% |
| Alpha Decay | 100.00% | ||
| 185 | 58 microseconds | Proton Emission | 90.00% |
| Alpha Decay | 10.00% | ||
| 186 | 15.0 milliseconds | Alpha Decay | 100.00% |
| 186m | 9.8 milliseconds | Alpha Decay | 100.00% |
| 187 | 37 milliseconds | Alpha Decay | 100.00% |
| 187m | 0.370 milliseconds | Alpha Decay | 100.00% |
| 188 | 265 milliseconds | Alpha Decay | 100.00% |
| Electron Capture (suspected) | No Data Available | ||
| 188m | 60 milliseconds | Alpha Decay | 100.00% |
| Electron Capture (suspected) | No Data Available | ||
| 189 | 674 milliseconds | Alpha Decay | > 50.00% |
| Electron Capture | < 50.00% | ||
| 189m | 5.0 milliseconds | Alpha Decay | > 50.00% |
| Electron Capture | < 50.00% | ||
| 190 | 6.3 seconds | Alpha Decay | 90.00% |
| Electron Capture | 10.00% | ||
| 190m | 6.2 seconds | Alpha Decay | 70.00% |
| Electron Capture | 30.00% | ||
| 191 | 12.4 seconds | Alpha Decay | 51.00% |
| Electron Capture | 49.00% | ||
| 191m | 125 milliseconds | Alpha Decay | 68.00% |
| Isomeric Transition | 32.00% | ||
| Electron Capture | No Data Available | ||
| 192 | 34.6 seconds | Electron Capture | 88.00% |
| Alpha Decay | 12.00% | ||
| 192m | 39.6 seconds | Electron Capture | 90.00% |
| Alpha Decay | 10.00% | ||
| 193 | 63.6 seconds | Electron Capture | 96.50% |
| Alpha Decay | 3.50% | ||
| 193m | 3.2 seconds | Alpha Decay | 84.00% |
| Electron Capture | 16.00% | ||
| 194 | 95 seconds | Electron Capture | 99.54% |
| Alpha Decay | 0.46% | ||
| 194m | 125 seconds | Electron Capture | 100.00% |
| 194m1 | 115 seconds | Electron Capture | 99.80% |
| Alpha Decay | 0.20% | ||
| 195 | 183 seconds | Electron Capture | 99.97% |
| Alpha Decay | 0.03% | ||
| 195m | 87 seconds | Electron Capture | 67.00% |
| Alpha Decay | 33.00% | ||
| 196 | 308 seconds | Electron Capture | 100.00% |
| Alpha Decay | 1.2×10-3 % | ||
| 196m | 0.6 seconds | Electron Capture | No Data Available |
| Isomeric Transition | No Data Available | ||
| 196m1 | 240 seconds | Electron Capture | 74.20% |
| Isomeric Transition | 25.80% | ||
| Alpha Decay | 3.8×10-4 % | ||
| 197 | 9.33 minutes | Electron Capture | 100.00% |
| Alpha Decay | 1.0×10-4 % | ||
| 197m | 5.04 minutes | Alpha Decay | 55.00% |
| Electron Capture | 45.00% | ||
| Isomeric Transition | < 0.30% | ||
| 198 | 10.3 minutes | Electron Capture | 100.00% |
| 198m | 11.6 minutes | Electron Capture | 100.00% |
| 198m1 | 7.7 seconds | Isomeric Transition | 100.00% |
| 199 | 27 minutes | Electron Capture | 100.00% |
| 199m | 24.70 minutes | Electron Capture | 99.00% |
| Isomeric Transition | <= 2.00% | ||
| Alpha Decay | ~ 0.01% | ||
| 200 | 36.4 minutes | Electron Capture | 100.00% |
| 200m | 31 minutes | Electron Capture | <= 100.00% |
| 200m1 | 0.40 seconds | Isomeric Transition | 100.00% |
| 201 | 103 minutes | Electron Capture | 100.00% |
| 201m | 57.5 minutes | Electron Capture | > 91.10% |
| Isomeric Transition | <= 8.60% | ||
| Alpha Decay | ~ 0.30% | ||
| 202 | 1.71 hours | Electron Capture | 100.00% |
| 203 | 11.76 hours | Electron Capture | 100.00% |
| 203m | 305 milliseconds | Isomeric Transition | 100.00% |
| 204 | 11.22 hours | Electron Capture | 100.00% |
| 204m | 13.0 milliseconds | Isomeric Transition | 100.00% |
| 204m1 | 1.07 milliseconds | Isomeric Transition | 100.00% |
| 205 | 15.31 days | Electron Capture | 100.00% |
| 206 | 6.243 days | Electron Capture | 100.00% |
| 206m | 0.89 milliseconds | Isomeric Transition | 100.00% |
| 207 | 31.55 years | Electron Capture | 100.00% |
| 208 | 3.68×10+5 years | Electron Capture | 100.00% |
| 208m | 2.58 milliseconds | Isomeric Transition | 100.00% |
| 209 | 1.9×10+19 years | Alpha Decay | 100.00% |
| 210 | 5.012 days | Beta-minus Decay | 100.00% |
| Alpha Decay | 1.3×10-4 % | ||
| 210m | 3.04×10+6 years | Alpha Decay | 100.00% |
| 211 | 2.14 minutes | Alpha Decay | 99.72% |
| Beta-minus Decay | 0.28% | ||
| 212 | 60.55 minutes | Beta-minus Decay | 64.06% |
| Alpha Decay | 35.94% | ||
| 212m | 25.0 minutes | Alpha Decay | 67.00% |
| Beta-minus Decay | 33.00% | ||
| Beta-minus Decay with delayed Alpha Decay | 30.00% | ||
| 212m1 | 7.0 minutes | Beta-minus Decay | 100.00% |
| 213 | 45.59 minutes | Beta-minus Decay | 97.80% |
| Alpha Decay | 2.20% | ||
| 214 | 19.9 minutes | Beta-minus Decay | 99.98% |
| Alpha Decay | 0.02% | ||
| 215 | 7.6 minutes | Beta-minus Decay | 100.00% |
| 215m | 36.9 seconds | Isomeric Transition | 76.2% |
| Beta-minus Decay | 23.8% | ||
| 216 | 2.25 minutes | Beta-minus Decay | <= 100.00% |
| 216m | 6.6 minutes | Beta-minus Decay | <= 100.00% |
| 217 | 98.5 seconds | Beta-minus Decay | 100.00% |
| 218 | 33 seconds | Beta-minus Decay | 100.00% |
| 219 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| 220 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| 221 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| Beta-minus Decay with delayed Neutron Emission | No Data Available | ||
| 222 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| 223 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| Beta-minus Decay with delayed Neutron Emission | No Data Available | ||
| 224 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| Beta-minus Decay with delayed Neutron Emission | No Data Available |
This page is maintained by Steve Gagnon.