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 |
| 184 | 0.02% | > 5.6×1013 years |
| 186 | 1.59% | 2.0×10+15 years |
| 187 | 1.96% | STABLE |
| 188 | 13.24% | STABLE |
| 189 | 16.15% | STABLE |
| 190 | 26.26% | STABLE |
| 192 | 40.78% | STABLE |
Known Isotopes
| Mass Number | Half-life | Decay Mode | Branching Percentage |
| 161 | 0.64 milliseconds | Alpha Decay | 100.00% |
| 162 | 2.1 milliseconds | Alpha Decay | ~ 99.00% |
| 163 | 5.5 milliseconds | Alpha Decay | 100.00% |
| Electron Capture | No Data Available | ||
| 164 | 21 milliseconds | Alpha Decay | 98.00% |
| Electron Capture | 2.00% | ||
| 165 | 71 milliseconds | Electron Capture | < 40.00% |
| Alpha Decay | > 60.00% | ||
| 166 | 199 milliseconds | Alpha Decay | 72.00% |
| Electron Capture | 18.00% | ||
| 167 | 0.81 seconds | Alpha Decay | 57.00% |
| Electron Capture | 43.00% | ||
| 168 | 2.1 seconds | Electron Capture | 57.00% |
| Alpha Decay | 43.00% | ||
| 169 | 3.43 seconds | Electron Capture | 86.30% |
| Alpha Decay | 13.70% | ||
| 170 | 7.37 seconds | Alpha Decay | 9.50% |
| Electron Capture | 90.50% | ||
| 171 | 8.3 seconds | Electron Capture | 98.20% |
| Alpha Decay | 1.80% | ||
| 172 | 19.2 seconds | Electron Capture | 99.80% |
| Alpha Decay | 0.20% | ||
| 173 | 22.4 seconds | Electron Capture | No Data Available |
| Alpha Decay | 0.4% | ||
| 174 | 44 seconds | Electron Capture | 99.98% |
| Alpha Decay | 0.02% | ||
| 175 | 1.4 minutes | Electron Capture | 100.00% |
| 176 | 3.6 minutes | Electron Capture | 100.00% |
| 177 | 3.0 minutes | Electron Capture | 100.00% |
| 178 | 5.0 minutes | Electron Capture | 100.00% |
| Alpha Decay | No Data Available | ||
| 179 | 6.5 minutes | Electron Capture | 100.00% |
| 180 | 21.5 minutes | Electron Capture | 100.00% |
| 181 | 105 minutes | Electron Capture | 100.00% |
| 181m | 2.7 minutes | Electron Capture | 100.00% |
| Isomeric Transition | <= 3.00% | ||
| 182 | 21.84 hours | Electron Capture | 100.00% |
| 182m | 0.78 milliseconds | Isomeric Transition | 100.00% |
| 183 | 13.0 hours | Electron Capture | 100.00% |
| 183m | 9.9 hours | Electron Capture | 85.00% |
| Isomeric Transition | 15.00% | ||
| 184 | > 5.6×1013 years | Alpha Decay | No Data Available |
| 185 | 93.6 days | Electron Capture | 100.00% |
| 186 | 2.0×10+15 years | Alpha Decay | 100.00% |
| 187 | STABLE | - | - |
| 188 | STABLE | - | - |
| 189 | STABLE | - | - |
| 189m | 5.81 hours | Isomeric Transition | 100.00% |
| 190 | STABLE | - | - |
| 190m | 9.9 minutes | Isomeric Transition | 100.00% |
| 191 | 15.4 days | Beta-minus Decay | 100.00% |
| 191m | 13.10 hours | Isomeric Transition | 100.00% |
| 192 | STABLE | - | - |
| 192m | 5.9 seconds | Isomeric Transition | > 87.00% |
| Beta-minus Decay | < 13.00% | ||
| 193 | 30.11 hours | Beta-minus Decay | 100.00% |
| 194 | 6.0 years | Beta-minus Decay | 100.00% |
| 195 | ≈ 9 minutes | Beta-minus Decay | No Data Available |
| 196 | 34.9 minutes | Beta-minus Decay | 100.00% |
| 197 | 2.8 minutes | Beta-minus Decay | 100.00% |
| 198 | No Data Available | Beta-minus Decay | 100.00% |
| 199 | 5 seconds | Beta-minus Decay | 100.00% |
| 200 | 6 seconds | Beta-minus Decay | 100.00% |
| 201 | > 300 nanoseconds | Beta-minus Decay (suspected) | No Data Available |
| 202 | > 300 nanoseconds | Beta-minus Decay (suspected) | No Data Available |
This page is maintained by Steve Gagnon.