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 |
| 138 | 0.08881% | 1.02×10+11 years |
| 139 | 99.9119% | STABLE |
Known Isotopes
| Mass Number | Half-life | Decay Mode | Branching Percentage |
| 117 | 23.5 milliseconds | Proton Emission | 93.90% |
| Electron Capture | 6.10% | ||
| 117m | 10 milliseconds | Proton Emission | 97.40% |
| Electron Capture | 2.60% | ||
| 118 | No Data Available | Electron Capture (suspected) | No Data Available |
| 119 | No Data Available | Electron Capture (suspected) | No Data Available |
| 120 | 2.8 seconds | Electron Capture | 100.00% |
| Electron Capture with delayed Proton Emission | > 0.00% | ||
| 121 | 5.3 seconds | Electron Capture | 100.00% |
| 122 | 8.6 seconds | Electron Capture | 100.00% |
| Electron Capture with delayed Proton Emission | No Data Available | ||
| 123 | 17 seconds | Electron Capture | 100.00% |
| 124 | 29.21 seconds | Electron Capture | 100.00% |
| 124m | 21 seconds | Electron Capture | 100.00% |
| 125 | 64.8 seconds | Electron Capture | 100.00% |
| 125m | 0.39 seconds | No Data Available | No Data Available |
| 126 | 54 seconds | Electron Capture | > 0.00% |
| 126m | < 50 seconds | Electron Capture | No Data Available |
| Isomeric Transition | No Data Available | ||
| 127 | 5.1 minutes | Electron Capture | 100.00% |
| 127m | 3.7 minutes | Electron Capture | 100.00% |
| Isomeric Transition | No Data Available | ||
| 128 | 5.18 minutes | Electron Capture | 100.00% |
| 128m | < 1.4 minutes | Electron Capture | 100.00% |
| 129 | 11.6 minutes | Electron Capture | 100.00% |
| 129m | 0.56 seconds | Isomeric Transition | 100.00% |
| 130 | 8.7 minutes | Electron Capture | 100.00% |
| 131 | 59 minutes | Electron Capture | 100.00% |
| 132 | 4.8 hours | Electron Capture | 100.00% |
| 132m | 24.3 minutes | Isomeric Transition | 76.00% |
| Electron Capture | 24.00% | ||
| 133 | 3.912 hours | Electron Capture | 100.00% |
| 134 | 6.45 minutes | Electron Capture | 100.00% |
| 135 | 19.5 hours | Electron Capture | 100.00% |
| 136 | 9.87 minutes | Electron Capture | 100.00% |
| 136m | 114 milliseconds | Isomeric Transition | 100.00% |
| 137 | 6×10+4 years | Electron Capture | 100.00% |
| 138 | 1.02×10+11 years | Electron Capture | 65.60% |
| Beta-minus Decay | 34.40% | ||
| 139 | STABLE | - | - |
| 140 | 1.67855 days | Beta-minus Decay | 100.00% |
| 141 | 3.92 hours | Beta-minus Decay | 100.00% |
| 142 | 91.1 minutes | Beta-minus Decay | 100.00% |
| 143 | 14.2 minutes | Beta-minus Decay | 100.00% |
| 144 | 40.8 seconds | Beta-minus Decay | 100.00% |
| 145 | 24.8 seconds | Beta-minus Decay | 100.00% |
| 146 | 6.27 seconds | Beta-minus Decay | 100.00% |
| 146m | 10.0 seconds | Beta-minus Decay | 100.00% |
| 147 | 4.06 seconds | Beta-minus Decay | 100.00% |
| Beta-minus Decay with delayed Neutron Emission | 0.04% | ||
| 148 | 1.26 seconds | Beta-minus Decay | 100.00% |
| Beta-minus Decay with delayed Neutron Emission | 0.15% | ||
| 149 | 1.05 seconds | Beta-minus Decay | 100.00% |
| Beta-minus Decay with delayed Neutron Emission | 1.43% | ||
| 150 | 0.86 seconds | Beta-minus Decay with delayed Neutron Emission | 2.70% |
| Beta-minus Decay | 100.00% | ||
| 151 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| Beta-minus Decay with delayed Neutron Emission | No Data Available | ||
| 152 | > 150 nanoseconds | Beta-minus Decay | 100.00% |
| 153 | > 100 nanoseconds | Beta-minus Decay (suspected) | No Data Available |
| 154 | No Data Available | Beta-minus Decay (suspected) | No Data Available |
| 155 | No Data Available | Beta-minus Decay (suspected) | No Data Available |
This page is maintained by Steve Gagnon.