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 |
| 203 | 29.524% | STABLE |
| 205 | 70.48% | STABLE |
Known Isotopes
| Mass Number | Half-life | Decay Mode | Branching Percentage |
| 176 | 5.2 milliseconds | Proton Emission | 100.00% |
| 177 | 18 milliseconds | Alpha Decay | 73.00% |
| Proton Emission | 27.00% | ||
| 178 | 254 milliseconds | Alpha Decay | ~ 53.00% |
| Electron Capture | ~ 47.00% | ||
| 179 | 0.23 seconds | Alpha Decay | < 100.00% |
| Electron Capture | No Data Available | ||
| Proton Emission | No Data Available | ||
| 179m | 1.5 milliseconds | Electron Capture | No Data Available |
| Isomeric Transition | No Data Available | ||
| Alpha Decay | <= 100.00% | ||
| Proton Emission | No Data Available | ||
| 180 | 1.09 seconds | Electron Capture | 94.00% |
| Alpha Decay | 6.00% | ||
| Electron Capture with delayed Spontaneous Fission | ~ 1.0×10-4 % | ||
| 181 | 3.2 seconds | Electron Capture | No Data Available |
| Alpha Decay | <= 10.00% | ||
| 181m | 1.40 milliseconds | Isomeric Transition | 99.60% |
| Alpha Decay | 0.40% | ||
| 182 | 3.1 seconds | Electron Capture | 97.50% |
| Alpha Decay | < 5.00% | ||
| 183 | 6.9 seconds | Alpha Decay | No Data Available |
| Electron Capture | > 0.00% | ||
| 183m | 53.3 milliseconds | Isomeric Transition | No Data Available |
| Electron Capture | No Data Available | ||
| Alpha Decay | 2.00% | ||
| 184 | 10.1 seconds | Electron Capture | 97.90% |
| Alpha Decay | 2.10% | ||
| 185 | 19.5 seconds | Electron Capture | No Data Available |
| 185m | 1.93 seconds | Alpha Decay | No Data Available |
| Isomeric Transition | No Data Available | ||
| 186 | 27.5 seconds | Alpha Decay | ~ 6.0×10-3 % |
| Electron Capture | 100.00% | ||
| 186m | 2.9 seconds | Isomeric Transition | 100.00% |
| 187 | ≈ 51 seconds | Electron Capture | 100.00% |
| Alpha Decay | ~ 0.03% | ||
| 187m | 15.60 seconds | Electron Capture | < 99.90% |
| Isomeric Transition | < 99.90% | ||
| Alpha Decay | 0.15% | ||
| 188 | 71 seconds | Electron Capture | 100.00% |
| Electron Capture | 100.00% | ||
| 188m | 41 milliseconds | Electron Capture | No Data Available |
| Isomeric Transition | 100.00% | ||
| 189 | 2.3 minutes | Electron Capture | 100.00% |
| 189m | 1.4 minutes | Electron Capture | < 100.00% |
| Isomeric Transition | < 4.00% | ||
| 190 | 2.6 minutes | Electron Capture | 100.00% |
| 190m | 3.7 minutes | Electron Capture | 100.00% |
| 190m1 | 0.75 milliseconds | Isomeric Transition | 100.00% |
| 191 | No Data Available | No Data Available | No Data Available |
| 191m | 5.22 minutes | No Data Available | No Data Available |
| 192 | 9.6 minutes | Electron Capture | 100.00% |
| 192m | 10.8 minutes | Electron Capture | 100.00% |
| 193 | 21.6 minutes | Electron Capture | 100.00% |
| 193m | 2.11 minutes | Isomeric Transition | <= 75.00% |
| Electron Capture | >= 25.00% | ||
| 194 | 33.0 minutes | Electron Capture | 100.00% |
| Alpha Decay | < 1.0×10-7 % | ||
| 194m | 32.8 minutes | Electron Capture | 100.00% |
| 195 | 1.16 hours | Electron Capture | 100.00% |
| 195m | 3.6 seconds | Isomeric Transition | 100.00% |
| 196 | 1.84 hours | Electron Capture | 100.00% |
| 196m | 1.41 hours | Electron Capture | 96.20% |
| Isomeric Transition | 3.80% | ||
| 197 | 2.84 hours | Electron Capture | 100.00% |
| 197m | 0.54 seconds | Isomeric Transition | 100.00% |
| 198 | 5.3 hours | Electron Capture | 100.00% |
| 198m | 1.87 hours | Electron Capture | 55.90% |
| Isomeric Transition | 44.10% | ||
| 198m1 | 32.1 milliseconds | Isomeric Transition | 100.00% |
| 199 | 7.42 hours | Electron Capture | 100.00% |
| 199m | 28.4 milliseconds | Isomeric Transition | 100.00% |
| 200 | 26.1 hours | Electron Capture | 100.00% |
| 200m | 34.0 milliseconds | Isomeric Transition | 100.00% |
| 201 | 3.0421 days | Electron Capture | 100.00% |
| 201m | 2.01 milliseconds | Isomeric Transition | 100.00% |
| 202 | 12.31 days | Electron Capture | 100.00% |
| 203 | STABLE | - | - |
| 204 | 3.783 years | Beta-minus Decay | 97.08% |
| Electron Capture | 2.92% | ||
| 205 | STABLE | - | - |
| 206 | 4.202 minutes | Beta-minus Decay | 100.00% |
| 206m | 3.74 minutes | Isomeric Transition | 100.00% |
| 207 | 4.77 minutes | Beta-minus Decay | 100.00% |
| 207m | 1.33 seconds | Isomeric Transition | 100.00% |
| 208 | 3.053 minutes | Beta-minus Decay | 100.00% |
| 209 | 2.161 minutes | Beta-minus Decay | 100.00% |
| 210 | 1.30 minutes | Beta-minus Decay | 100.00% |
| Beta-minus Decay with delayed Neutron Emission | 7.0×10-3 % | ||
| 211 | > 300 nanoseconds | Beta-minus Decay (suspected) | No Data Available |
| 212 | > 300 nanoseconds | Beta-minus Decay (suspected) | No Data Available |
| 213 | 101 seconds | Beta-minus Decay | No Data Available |
| 214 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| Beta-minus Decay with delayed Neutron Emission | No Data Available | ||
| 215 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| Beta-minus Decay with delayed Neutron Emission | No Data Available | ||
| 216 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| Beta-minus Decay with delayed Neutron Emission | No Data Available | ||
| 217 | > 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.