It's Elemental
Isotopes of the Element Cesium
Cesium
Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information.
Isotopes With A Known Natural Abundance
| Mass Number | Natural Abundance | Half-life |
| 133 | 100% | STABLE |
Known Isotopes
| Mass Number | Half-life | Decay Mode | Branching Percentage |
| 112 | 0.5 milliseconds | Proton Emission | 100.00% |
| 113 | 16.7 microseconds | Proton Emission | 100.00% |
| Alpha Decay | No Data Available | ||
| 114 | 0.57 seconds | Electron Capture | 99.98% |
| Electron Capture with delayed Proton Emission | 8.70% | ||
| Electron Capture with delayed Alpha Decay | 0.19% | ||
| Alpha Decay | 0.02% | ||
| 115 | 1.4 seconds | Electron Capture | 100.00% |
| Electron Capture with delayed Proton Emission | ~ 0.07% | ||
| 116 | 0.70 seconds | Electron Capture | 100.00% |
| Electron Capture with delayed Proton Emission | 2.80% | ||
| Electron Capture with delayed Alpha Decay | 0.05% | ||
| 116m | 3.85 seconds | Electron Capture | 100.00% |
| Electron Capture with delayed Proton Emission | 0.51% | ||
| Electron Capture with delayed Alpha Decay | 8.0×10-3 % | ||
| 117 | 8.4 seconds | Electron Capture | 100.00% |
| 117m | 6.5 seconds | Electron Capture | No Data Available |
| 118 | 14 seconds | Electron Capture | 100.00% |
| Electron Capture with delayed Proton Emission | < 0.04% | ||
| Electron Capture with delayed Alpha Decay | < 2.4×10-3 % | ||
| 118m | 17 seconds | Electron Capture | 100.00% |
| Electron Capture with delayed Proton Emission | < 0.04% | ||
| Electron Capture with delayed Alpha Decay | < 2.4×10-3 % | ||
| 119 | 43.0 seconds | Electron Capture | 100.00% |
| 119m | 30.4 seconds | Electron Capture | 100.00% |
| 120 | 61.3 seconds | Electron Capture | 100.00% |
| Electron Capture with delayed Alpha Decay | 2.0×10-5 % | ||
| Electron Capture with delayed Proton Emission | 7.0×10-6 % | ||
| 120m | 57 seconds | Electron Capture | 100.00% |
| 121 | 155 seconds | Electron Capture | 100.00% |
| 121m | 122 seconds | Isomeric Transition | 17.00% |
| Electron Capture | 83.00% | ||
| 122 | 21.18 seconds | Electron Capture | 100.00% |
| 122m | 0.36 seconds | Isomeric Transition | 100.00% |
| 122m1 | 3.70 minutes | Electron Capture | 100.00% |
| 123 | 5.88 minutes | Electron Capture | 100.00% |
| 123m | 1.64 seconds | Isomeric Transition | 100.00% |
| 124 | 30.9 seconds | Electron Capture | 100.00% |
| 124m | 6.3 seconds | Isomeric Transition | 100.00% |
| 125 | 46.7 minutes | Electron Capture | 100.00% |
| 125m | 0.90 milliseconds | Isomeric Transition | 100.00% |
| 126 | 1.64 minutes | Electron Capture | 100.00% |
| 127 | 6.25 hours | Electron Capture | 100.00% |
| 128 | 3.66 minutes | Electron Capture | 100.00% |
| 129 | 32.06 hours | Electron Capture | 100.00% |
| 130 | 29.21 minutes | Electron Capture | 98.40% |
| Beta-minus Decay | 1.60% | ||
| 130m | 3.46 minutes | Isomeric Transition | 99.84% |
| Electron Capture | 0.16% | ||
| 131 | 9.689 days | Electron Capture | 100.00% |
| 132 | 6.480 days | Electron Capture | 98.13% |
| Beta-minus Decay | 1.87% | ||
| 133 | STABLE | - | - |
| 134 | 2.0652 years | Beta-minus Decay | 100.00% |
| Electron Capture | 3.0×10-4 % | ||
| 134m | 2.912 hours | Isomeric Transition | 100.00% |
| 135 | 2.3×10+6 years | Beta-minus Decay | 100.00% |
| 135m | 53 minutes | Isomeric Transition | 100.00% |
| 136 | 13.04 days | Beta-minus Decay | 100.00% |
| 136m | 17.5 seconds | Beta-minus Decay | No Data Available |
| Isomeric Transition | > 0.00% | ||
| 137 | 30.08 years | Beta-minus Decay | 100.00% |
| 138 | 33.41 minutes | Beta-minus Decay | 100.00% |
| 138m | 2.91 minutes | Isomeric Transition | 81.00% |
| Beta-minus Decay | 19.00% | ||
| 139 | 9.27 minutes | Beta-minus Decay | 100.00% |
| 140 | 63.7 seconds | Beta-minus Decay | 100.00% |
| 141 | 24.84 seconds | Beta-minus Decay | 100.00% |
| Beta-minus Decay with delayed Neutron Emission | 0.04% | ||
| 142 | 1.684 seconds | Beta-minus Decay | 100.00% |
| Beta-minus Decay with delayed Neutron Emission | 0.09% | ||
| 143 | 1.791 seconds | Beta-minus Decay | 100.00% |
| Beta-minus Decay with delayed Neutron Emission | 1.64% | ||
| 144 | 0.994 seconds | Beta-minus Decay | 100.00% |
| Beta-minus Decay with delayed Neutron Emission | 3.03% | ||
| 144m | < 1 seconds | Beta-minus Decay | No Data Available |
| 145 | 0.587 seconds | Beta-minus Decay | 100.00% |
| Beta-minus Decay with delayed Neutron Emission | 14.70% | ||
| 146 | 0.321 seconds | Beta-minus Decay | 100.00% |
| Beta-minus Decay with delayed Neutron Emission | 14.20% | ||
| 147 | 0.230 seconds | Beta-minus Decay | 100.00% |
| Beta-minus Decay with delayed Neutron Emission | 28.50% | ||
| 148 | 146 milliseconds | Beta-minus Decay | 100.00% |
| Beta-minus Decay with delayed Neutron Emission | 25.10% | ||
| 149 | > 50 milliseconds | Beta-minus Decay | No Data Available |
| Beta-minus Decay with delayed Neutron Emission | No Data Available | ||
| 150 | > 50 milliseconds | Beta-minus Decay | No Data Available |
| Beta-minus Decay with delayed Neutron Emission | No Data Available | ||
| 151 | > 50 milliseconds | Beta-minus Decay | No Data Available |
| Beta-minus Decay with delayed Neutron Emission | No Data Available |
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