Most of the isotope data on this site has been obtained from the National Nuclear Data Center.
Naturally Occurring Isotopes
Californium has no naturally occurring isotopes.
Known Isotopes
| Mass Number | Half-life | Decay Mode | Branching Percentage |
| 237 | 0.8 seconds | Spontaneous Fission | 70.00% |
| Alpha Decay | 30.00% | ||
| 238 | 21 milliseconds | Spontaneous Fission | 100.00% |
| 239 | 39 seconds | Electron Capture | No Data Available |
| Alpha Decay | No Data Available | ||
| 240 | 64 seconds | Alpha Decay | 98.50% |
| Spontaneous Fission | 1.50% | ||
| 241 | 3.78 minutes | Electron Capture | ~ 75.00% |
| Alpha Decay | ~ 25.00% | ||
| 242 | 3.7 minutes | Alpha Decay | 80.00% |
| Electron Capture | 20.00% | ||
| Spontaneous Fission | <= 0.01% | ||
| 243 | 10.7 minutes | Alpha Decay | ~ 14.00% |
| Electron Capture | ~ 86.00% | ||
| 244 | 19.4 minutes | Alpha Decay | <= 100.00% |
| 245 | 45.0 minutes | Electron Capture | 64.70% |
| Alpha Decay | 35.30% | ||
| 246 | 35.7 hours | Alpha Decay | 100.00% |
| Electron Capture | < 4.0×10-3 % | ||
| Spontaneous Fission | 2.4×10-4 % | ||
| 246m | 45 nanoseconds | Spontaneous Fission | <= 100.00% |
| 247 | 3.11 hours | Electron Capture | 99.97% |
| Alpha Decay | 0.04% | ||
| 248 | 333.5 days | Alpha Decay | 100.00% |
| Spontaneous Fission | 2.9×10-3 % | ||
| 249 | 351 years | Alpha Decay | 100.00% |
| Spontaneous Fission | 5.0×10-7 % | ||
| 250 | 13.08 years | Alpha Decay | 99.92% |
| Spontaneous Fission | 0.08% | ||
| 251 | 898 years | Alpha Decay | 100.00% |
| Spontaneous Fission | No Data Available | ||
| 252 | 2.645 years | Alpha Decay | 96.91% |
| Spontaneous Fission | 3.09% | ||
| 253 | 17.81 days | Alpha Decay | 0.31% |
| Beta-minus Decay | 99.69% | ||
| 254 | 60.5 days | Spontaneous Fission | 99.69% |
| Alpha Decay | 0.31% | ||
| 255 | 85 minutes | Beta-minus Decay | 100.00% |
| 256 | 12.3 minutes | Spontaneous Fission | 100.00% |
| Beta-minus Decay | < 1.00% | ||
| Alpha Decay | ~ 1.0×10-6 % |
This page is maintained by Steve Gagnon.