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 |
| 190 | 0.012% | 6.5×10+11 years |
| 192 | 0.782% | STABLE |
| 194 | 32.86% | STABLE |
| 195 | 33.78% | STABLE |
| 196 | 25.21% | STABLE |
| 198 | 7.36% | STABLE |
Known Isotopes
| Mass Number | Half-life | Decay Mode | Branching Percentage |
| 166 | 300 microseconds | Alpha Decay | 100.00% |
| 167 | 0.9 milliseconds | Alpha Decay | 100.00% |
| 168 | 2.02 milliseconds | Alpha Decay | 100.00% |
| 169 | 7.0 milliseconds | Alpha Decay | 100.00% |
| 170 | 13.8 milliseconds | Alpha Decay | 98.00% |
| Electron Capture | No Data Available | ||
| 171 | 45.5 milliseconds | Alpha Decay | 90.00% |
| Electron Capture | 10.00% | ||
| 172 | 97.6 milliseconds | Alpha Decay | 94.00% |
| Electron Capture | 6.00% | ||
| 173 | 382 milliseconds | Alpha Decay | 100.00% |
| Electron Capture (suspected) | No Data Available | ||
| 174 | 0.889 seconds | Electron Capture | 24.00% |
| Alpha Decay | 76.00% | ||
| 175 | 2.53 seconds | Alpha Decay | 64.00% |
| Electron Capture | 36.00% | ||
| 176 | 6.33 seconds | Electron Capture | 60.00% |
| Alpha Decay | 40.00% | ||
| 177 | 10.6 seconds | Electron Capture | 94.30% |
| Alpha Decay | 5.70% | ||
| 178 | 20.7 seconds | Electron Capture | 92.30% |
| Alpha Decay | 7.70% | ||
| 179 | 21.2 seconds | Electron Capture | 99.76% |
| Alpha Decay | 0.24% | ||
| 180 | 56 seconds | Electron Capture | 100.00% |
| Alpha Decay | ~ 0.30% | ||
| 181 | 52.0 seconds | Electron Capture | 100.00% |
| Alpha Decay | ~ 0.08% | ||
| 182 | 2.67 minutes | Electron Capture | 99.96% |
| Alpha Decay | 0.04% | ||
| 183 | 6.5 minutes | Electron Capture | 100.00% |
| Alpha Decay | ~ 1.3×10-3 % | ||
| 183m | 43 seconds | Isomeric Transition | No Data Available |
| Electron Capture | 100.00% | ||
| Alpha Decay | < 4.0×10-4 % | ||
| 184 | 17.3 minutes | Electron Capture | 100.00% |
| Alpha Decay | ~ 1.0×10-3 % | ||
| 184m | 1.01 milliseconds | Isomeric Transition | 100.00% |
| 185 | 70.9 minutes | Electron Capture | < 100.00% |
| 185m | 33.0 minutes | Electron Capture | 99.00% |
| Isomeric Transition | < 2.00% | ||
| 186 | 2.08 hours | Electron Capture | 100.00% |
| Alpha Decay | ~ 1.4×10-4 % | ||
| 187 | 2.35 hours | Electron Capture | 100.00% |
| 188 | 10.2 days | Alpha Decay | 2.6×10-5 % |
| Electron Capture | 100.00% | ||
| 189 | 10.87 hours | Electron Capture | 100.00% |
| 190 | 6.5×10+11 years | Alpha Decay | 100.00% |
| 191 | 2.83 days | Electron Capture | 100.00% |
| 192 | STABLE | - | - |
| 193 | 50 years | Electron Capture | 100.00% |
| 193m | 4.33 days | Isomeric Transition | 100.00% |
| 194 | STABLE | - | - |
| 195 | STABLE | - | - |
| 195m | 4.010 days | Isomeric Transition | 100.00% |
| 196 | STABLE | - | - |
| 197 | 19.8915 hours | Beta-minus Decay | 100.00% |
| 197m | 95.41 minutes | Isomeric Transition | 96.70% |
| Beta-minus Decay | 3.30% | ||
| 198 | STABLE | - | - |
| 199 | 30.80 minutes | Beta-minus Decay | 100.00% |
| 199m | 13.6 seconds | Isomeric Transition | 100.00% |
| 200 | 12.6 hours | Beta-minus Decay | 100.00% |
| 201 | 2.5 minutes | Beta-minus Decay | 100.00% |
| 202 | 44 hours | Beta-minus Decay | 100.00% |
| 202m | 0.28 milliseconds | Isomeric Transition | 100.00% |
| 203 | 10 seconds | Beta-minus Decay | 100.00% |
| 204 | 10.3 seconds | Beta-minus Decay | 100.00% |
| 205 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
This page is maintained by Steve Gagnon.