[Click for Main Data] Proton Emission Neutron Emission Electron Emission Positron Emission
Most of the isotope data on this site has been obtained from the National Nuclear Data Center.
Naturally Occurring Isotopes
Francium has no naturally occurring isotopes.
Known Isotopes
| Mass Number | Half-life | Decay Mode | Branching Percentage |
| 199 | 12 milliseconds | Alpha Decay | > 0.00% |
| Electron Capture | No Data Available | ||
| 200 | 49 milliseconds | Alpha Decay | 100.00% |
| 201 | 62 milliseconds | Alpha Decay | 100.00% |
| 201m | 19 milliseconds | Alpha Decay | 100.00% |
| 202 | 0.30 seconds | Alpha Decay | 100.00% |
| 202m | 0.29 seconds | Alpha Decay | 100.00% |
| 203 | 0.55 seconds | Alpha Decay | <= 100.00% |
| 204 | 1.8 seconds | Alpha Decay | 92.00% |
| Electron Capture | 8.00% | ||
| 204m | 1.6 seconds | Alpha Decay | 90.00% |
| Electron Capture | 10.00% | ||
| 204m1 | 0.8 seconds | Alpha Decay | 74.00% |
| Electron Capture | 26.00% | ||
| 205 | 3.97 seconds | Alpha Decay | 98.50% |
| Electron Capture | 1.50% | ||
| 206 | ≈ 16 seconds | Alpha Decay | ~ 84.00% |
| Electron Capture | ~ 16.00% | ||
| Electron Capture | ~ 16.00% | ||
| Alpha Decay | ~ 84.00% | ||
| 206m | 0.7 seconds | Isomeric Transition | 95.00% |
| Alpha Decay | 5.00% | ||
| 207 | 14.8 seconds | Alpha Decay | 95.00% |
| Electron Capture | 5.00% | ||
| 208 | 59.1 seconds | Alpha Decay | 89.00% |
| Electron Capture | 11.00% | ||
| 209 | 50.5 seconds | Alpha Decay | 89.00% |
| Electron Capture | 11.00% | ||
| 210 | 3.18 minutes | Alpha Decay | 71.00% |
| Electron Capture | 29.00% | ||
| 211 | 3.10 minutes | Alpha Decay | 87.00% |
| Electron Capture | 13.00% | ||
| 212 | 20.0 minutes | Electron Capture | 57.00% |
| Alpha Decay | 43.00% | ||
| 213 | 34.82 seconds | Alpha Decay | 99.44% |
| Electron Capture | 0.56% | ||
| 214 | 5.0 milliseconds | Alpha Decay | 100.00% |
| 214m | 3.35 milliseconds | Alpha Decay | 100.00% |
| 215 | 86 nanoseconds | Alpha Decay | 100.00% |
| 216 | 700 nanoseconds | Alpha Decay | 100.00% |
| 217 | 19 microseconds | Alpha Decay | 100.00% |
| 218 | 1.0 milliseconds | Alpha Decay | 100.00% |
| 218m | 22.0 milliseconds | Alpha Decay | <= 100.00% |
| Isomeric Transition | No Data Available | ||
| 219 | 20 milliseconds | Alpha Decay | 100.00% |
| 220 | 27.4 seconds | Alpha Decay | 99.65% |
| Beta-minus Decay | 0.35% | ||
| 221 | 286.1 seconds | Alpha Decay | 100.00% |
| Beta-minus Decay | < 0.10% | ||
| 222 | 14.2 minutes | Beta-minus Decay | 100.00% |
| 223 | 22.00 minutes | Alpha Decay | 6.0×10-3 % |
| Beta-minus Decay | 99.99% | ||
| 224 | 3.33 minutes | Beta-minus Decay | 100.00% |
| 225 | 3.95 minutes | Beta-minus Decay | 100.00% |
| 226 | 49 seconds | Beta-minus Decay | 100.00% |
| 227 | 2.47 minutes | Beta-minus Decay | 100.00% |
| 228 | 38 seconds | Beta-minus Decay | <= 100.00% |
| 229 | 50.2 seconds | Beta-minus Decay | 100.00% |
| 230 | 19.1 seconds | Beta-minus Decay | 100.00% |
| 231 | 17.6 seconds | Beta-minus Decay | 100.00% |
| 232 | 5.5 seconds | Beta-minus Decay | 100.00% |
| 233 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
This page is maintained by Steve Gagnon.