It's Elemental
Isotopes of the Element Neptunium
Neptunium
Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information.
Known Isotopes
| Mass Number | Half-life | Decay Mode | Branching Percentage |
| 225 | No Data Available | Alpha Decay | 100.00% |
| 226 | 35 milliseconds | Alpha Decay | 100.00% |
| 227 | 0.51 seconds | Alpha Decay | 100.00% |
| 228 | 61.4 seconds | Electron Capture | 60.00% |
| Alpha Decay | 40.00% | ||
| 229 | 4.0 minutes | Alpha Decay | 68.00% |
| Electron Capture | 32.00% | ||
| 230 | 4.6 minutes | Electron Capture | <= 97.00% |
| Alpha Decay | >= 3.00% | ||
| 231 | 48.8 minutes | Electron Capture | 98.00% |
| Alpha Decay | 2.00% | ||
| 232 | 14.7 minutes | Electron Capture | 100.00% |
| Alpha Decay | 2.0×10-4 % | ||
| 233 | 36.2 minutes | Electron Capture | 100.00% |
| Alpha Decay | <= 1.0×10-3 % | ||
| 234 | 4.4 days | Electron Capture | 100.00% |
| 235 | 396.1 days | Electron Capture | 100.00% |
| Alpha Decay | 2.6×10-3 % | ||
| 236 | 153×10+3 years | Electron Capture | 86.30% |
| Beta-minus Decay | 13.50% | ||
| Alpha Decay | 0.16% | ||
| 236m | 22.5 hours | Beta-minus Decay | 50.00% |
| Electron Capture | 50.00% | ||
| 237 | 2.144×10+6 years | Alpha Decay | 100.00% |
| Spontaneous Fission | <= 2×10-10 % | ||
| 238 | 2.117 days | Beta-minus Decay | 100.00% |
| 239 | 2.356 days | Beta-minus Decay | 100.00% |
| 240 | 61.9 minutes | Beta-minus Decay | 100.00% |
| 240m | 7.22 minutes | Beta-minus Decay | 99.88% |
| Isomeric Transition | 0.12% | ||
| 241 | 13.9 minutes | Beta-minus Decay | 100.00% |
| 242 | 2.2 minutes | Beta-minus Decay | 100.00% |
| 242m | 5.5 minutes | Beta-minus Decay | 100.00% |
| 243 | 1.85 minutes | Beta-minus Decay | 100.00% |
| 244 | 2.29 minutes | Beta-minus Decay | 100.00% |
| 245 | No Data Available | No Data Available | No Data Available |
Citation and linking information
For questions about this page, please contact Carol McKisson.