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 |
| 196 | 0.15% | STABLE |
| 198 | 9.97% | STABLE |
| 199 | 16.87% | STABLE |
| 200 | 23.10% | STABLE |
| 201 | 13.18% | STABLE |
| 202 | 29.86% | STABLE |
| 204 | 6.87% | STABLE |
Known Isotopes
| Mass Number | Half-life | Decay Mode | Branching Percentage |
| 171 | 59 microseconds | Alpha Decay | 100.00% |
| 172 | 231 microseconds | Alpha Decay | 100.00% |
| 173 | 0.6 milliseconds | Alpha Decay | 100.00% |
| 174 | 2.1 milliseconds | Alpha Decay | 99.60% |
| 175 | 10.6 milliseconds | Alpha Decay | 100.00% |
| 176 | 20.3 milliseconds | Alpha Decay | 94.00% |
| 177 | 118 milliseconds | Alpha Decay | 100.00% |
| 178 | 266.5 milliseconds | Alpha Decay | ~ 70.00% |
| Electron Capture | ~ 30.00% | ||
| 179 | 1.05 seconds | Electron Capture | 45.00% |
| Electron Capture with delayed Proton Emission | ~ 0.15% | ||
| Alpha Decay | 55.00% | ||
| 180 | 2.58 seconds | Electron Capture | 52.00% |
| Alpha Decay | 48.00% | ||
| 181 | 3.6 seconds | Electron Capture | 73.00% |
| Alpha Decay | 27.00% | ||
| Electron Capture with delayed Proton Emission | 0.01% | ||
| Electron Capture with delayed Alpha Decay | 9.0×10-6 % | ||
| 182 | 10.83 seconds | Electron Capture | 84.80% |
| Alpha Decay | 15.20% | ||
| 183 | 9.4 seconds | Alpha Decay | 11.70% |
| Electron Capture with delayed Proton Emission | 2.6×10-4 % | ||
| Electron Capture | 88.30% | ||
| 184 | 30.87 seconds | Electron Capture | 98.89% |
| Alpha Decay | 1.11% | ||
| 185 | 49.1 seconds | Electron Capture | 94.00% |
| Alpha Decay | 6.00% | ||
| 185m | 21.6 seconds | Isomeric Transition | 54.00% |
| Electron Capture | 46.00% | ||
| Alpha Decay | ~ 0.03% | ||
| 186 | 1.38 minutes | Alpha Decay | 0.02% |
| Electron Capture | 99.98% | ||
| 187 | 2.4 minutes | Electron Capture | 100.00% |
| Alpha Decay | < 3.7×10-4 % | ||
| 187m | 1.9 minutes | Electron Capture | 100.00% |
| Alpha Decay | < 3.7×10-4 % | ||
| 188 | 3.25 minutes | Electron Capture | 100.00% |
| Alpha Decay | 3.7×10-5 % | ||
| 189 | 7.6 minutes | Electron Capture | 100.00% |
| Alpha Decay | < 3.0×10-5 % | ||
| 189m | 8.6 minutes | Electron Capture | 100.00% |
| Alpha Decay | < 3.0×10-5 % | ||
| 190 | 20.0 minutes | Electron Capture | 100.00% |
| Alpha Decay | < 3.4×10-7 % | ||
| 191 | 49 minutes | Electron Capture | 100.00% |
| Alpha Decay | 5.0×10-6 % | ||
| 191m | 50.8 minutes | Electron Capture | 100.00% |
| 192 | 4.85 hours | Electron Capture | 100.00% |
| 193 | 3.80 hours | Electron Capture | 100.00% |
| 193m | 11.8 hours | Electron Capture | 92.80% |
| Isomeric Transition | 7.20% | ||
| 194 | 444 years | Electron Capture | 100.00% |
| 195 | 10.53 hours | Electron Capture | 100.00% |
| 195m | 41.6 hours | Isomeric Transition | 54.20% |
| Electron Capture | 45.80% | ||
| 196 | STABLE | - | - |
| 197 | 64.14 hours | Electron Capture | 100.00% |
| 197m | 23.8 hours | Isomeric Transition | 91.40% |
| Electron Capture | 8.60% | ||
| 198 | STABLE | - | - |
| 199 | STABLE | - | - |
| 199m | 42.67 minutes | Isomeric Transition | 100.00% |
| 200 | STABLE | - | - |
| 201 | STABLE | - | - |
| 202 | STABLE | - | - |
| 203 | 46.594 days | Beta-minus Decay | 100.00% |
| 204 | STABLE | - | - |
| 205 | 5.14 minutes | Beta-minus Decay | 100.00% |
| 205m | 1.09 milliseconds | Isomeric Transition | 100.00% |
| 206 | 8.32 minutes | Beta-minus Decay | 100.00% |
| 207 | 2.9 minutes | Beta-minus Decay | 100.00% |
| 208 | 41 minutes | Beta-minus Decay | 100.00% |
| 209 | 35 seconds | Beta-minus Decay | 100.00% |
| 210 | > 300 nanoseconds | Beta-minus Decay (suspected) | No Data Available |
| 211 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| Beta-minus Decay with delayed Neutron Emission | No Data Available | ||
| 212 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| Beta-minus Decay with delayed Neutron Emission | No Data Available | ||
| 213 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| Beta-minus Decay with delayed Neutron Emission | 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 with delayed Neutron Emission | No Data Available |
| Beta-minus Decay | No Data Available |
This page is maintained by Steve Gagnon.