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 |
| 191 | 37.3% | STABLE |
| 193 | 62.7% | STABLE |
Known Isotopes
| Mass Number | Half-life | Decay Mode | Branching Percentage |
| 164 | 94 microseconds | Proton Emission | > 0.00% |
| Alpha Decay | No Data Available | ||
| Electron Capture | No Data Available | ||
| 165 | 1 microseconds | Proton Emission (suspected) | No Data Available |
| Alpha Decay (suspected) | No Data Available | ||
| 165m | 0.30 milliseconds | Alpha Decay | 13.00% |
| Proton Emission | 87.00% | ||
| 166 | 10.5 milliseconds | Alpha Decay | 93.00% |
| Proton Emission | 7.00% | ||
| 166m | 15.1 milliseconds | Alpha Decay | 98.20% |
| Proton Emission | 1.80% | ||
| 167 | 35.2 milliseconds | Alpha Decay | 48.00% |
| Proton Emission | 32.00% | ||
| Electron Capture | 20.00% | ||
| 167m | 25.7 milliseconds | Proton Emission | 0.40% |
| Alpha Decay | 80.00% | ||
| Electron Capture | 20.00% | ||
| 168 | 222 milliseconds | Alpha Decay | <= 100.00% |
| Electron Capture | No Data Available | ||
| Proton Emission | No Data Available | ||
| 168m | 159 milliseconds | Alpha Decay | 77.00% |
| Electron Capture | <= 23.00% | ||
| Proton Emission | No Data Available | ||
| 169 | 0.353 seconds | Alpha Decay | 45.00% |
| Electron Capture | No Data Available | ||
| Proton Emission | No Data Available | ||
| 169m | 0.281 seconds | Electron Capture | No Data Available |
| Proton Emission | No Data Available | ||
| Alpha Decay | 72.00% | ||
| 170 | 0.87 seconds | Electron Capture | 94.80% |
| Alpha Decay | 5.20% | ||
| 170m | 811 milliseconds | Isomeric Transition | <= 62.00% |
| Electron Capture | <= 62.00% | ||
| Alpha Decay | 38.00% | ||
| 171 | 3.2 seconds | Alpha Decay | > 0.00% |
| Proton Emission | No Data Available | ||
| Electron Capture | No Data Available | ||
| 171m | 1.40 seconds | Proton Emission | <= 42.00% |
| Electron Capture | <= 42.00% | ||
| Alpha Decay | 58.00% | ||
| 172 | 4.4 seconds | Electron Capture | 98.00% |
| Alpha Decay | ~ 2.00% | ||
| 172m | 2.0 seconds | Electron Capture | 77.00% |
| Alpha Decay | 23.00% | ||
| 173 | 9.0 seconds | Electron Capture | > 93.00% |
| Alpha Decay | < 7.00% | ||
| 173m | 2.4 seconds | Electron Capture | No Data Available |
| Alpha Decay | 7.00% | ||
| 174 | 7.9 seconds | Electron Capture | 99.50% |
| Alpha Decay | 0.50% | ||
| 174m | 4.9 seconds | Electron Capture | 97.50% |
| Alpha Decay | 2.50% | ||
| 175 | 9 seconds | Electron Capture | 99.15% |
| Alpha Decay | 0.85% | ||
| 176 | 8.7 seconds | Electron Capture | 96.90% |
| Alpha Decay | 3.10% | ||
| 177 | 30 seconds | Electron Capture | 99.94% |
| Alpha Decay | 0.06% | ||
| 178 | 12 seconds | Electron Capture | 100.00% |
| 179 | 79 seconds | Electron Capture | 100.00% |
| 180 | 1.5 minutes | Electron Capture | 100.00% |
| 181 | 4.90 minutes | Electron Capture | 100.00% |
| 182 | 15 minutes | Electron Capture | 100.00% |
| 183 | 57 minutes | Electron Capture | 100.00% |
| 184 | 3.09 hours | Electron Capture | 100.00% |
| 185 | 14.4 hours | Electron Capture | 100.00% |
| 186 | 16.64 hours | Electron Capture | 100.00% |
| 186m | 1.90 hours | Electron Capture | ~ 75.00% |
| Isomeric Transition | ~ 25.00% | ||
| 187 | 10.5 hours | Electron Capture | 100.00% |
| 187m | 30.3 milliseconds | Isomeric Transition | 100.00% |
| 188 | 41.5 hours | Electron Capture | 100.00% |
| 188m | 4.2 milliseconds | Electron Capture (suspected) | No Data Available |
| Isomeric Transition | No Data Available | ||
| 189 | 13.2 days | Electron Capture | 100.00% |
| 189m | 13.3 milliseconds | Isomeric Transition | 100.00% |
| 189m1 | 3.7 milliseconds | Isomeric Transition | 100.00% |
| 190 | 11.78 days | Electron Capture | 100.00% |
| 190m | 1.120 hours | Isomeric Transition | 100.00% |
| 190m1 | 3.087 hours | Isomeric Transition | 8.60% |
| Electron Capture | 91.40% | ||
| 191 | STABLE | - | - |
| 191m | 4.899 seconds | Isomeric Transition | 100.00% |
| 191m1 | 5.5 seconds | Isomeric Transition | 100.00% |
| 192 | 73.829 days | Beta-minus Decay | 95.24% |
| Electron Capture | 4.76% | ||
| 192m | 1.45 minutes | Isomeric Transition | 99.98% |
| Beta-minus Decay | 0.02% | ||
| 192m1 | 241 years | Isomeric Transition | 100.00% |
| 193 | STABLE | - | - |
| 193m | 10.53 days | Isomeric Transition | 100.00% |
| 194 | 19.28 hours | Beta-minus Decay | 100.00% |
| 194m | 31.85 milliseconds | Isomeric Transition | 100.00% |
| 194m1 | 171 days | Beta-minus Decay | 100.00% |
| 195 | 2.5 hours | Beta-minus Decay | 100.00% |
| 195m | 3.8 hours | Beta-minus Decay | 95.00% |
| Isomeric Transition | 5.00% | ||
| 196 | 52 seconds | Beta-minus Decay | 100.00% |
| 196m | 1.40 hours | Beta-minus Decay | 100.00% |
| Isomeric Transition | < 0.30% | ||
| 197 | 5.8 minutes | Beta-minus Decay | 100.00% |
| 197m | 8.9 minutes | Isomeric Transition | 0.25% |
| Beta-minus Decay | 99.75% | ||
| 198 | 8 seconds | Beta-minus Decay | 100.00% |
| 199 | 6 seconds | Beta-minus Decay | No Data Available |
| 200 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| 201 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| 202 | 11 seconds | Beta-minus Decay | 100.00% |
| 203 | > 300 nanoseconds | Beta-minus Decay (suspected) | No Data Available |
| 204 | No Data Available | No Data Available | No Data Available |
This page is maintained by Steve Gagnon.