[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
Radon has no naturally occurring isotopes.
Known Isotopes
| Mass Number | Half-life | Decay Mode | Branching Percentage |
| 193 | 1.15 milliseconds | Alpha Decay | 100.00% |
| 194 | 0.78 milliseconds | Alpha Decay | 100.00% |
| 195 | 6 milliseconds | Alpha Decay | 100.00% |
| 195m | 5 milliseconds | Alpha Decay | 100.00% |
| 196 | 4.4 milliseconds | Alpha Decay | 99.90% |
| Electron Capture | ~ 0.10% | ||
| 197 | 53 milliseconds | Alpha Decay | 100.00% |
| 197m | 25 milliseconds | Alpha Decay | 100.00% |
| 198 | 65 milliseconds | Alpha Decay | No Data Available |
| Electron Capture | No Data Available | ||
| 199 | 0.59 seconds | Alpha Decay | 94.00% |
| Electron Capture | 6.00% | ||
| 199m | 0.31 seconds | Alpha Decay | 97.00% |
| Electron Capture | 3.00% | ||
| 200 | 1.03 seconds | Alpha Decay | 86.00% |
| Electron Capture | 14.00% | ||
| 201 | 7.0 seconds | Alpha Decay | No Data Available |
| Electron Capture | No Data Available | ||
| 201m | 3.8 seconds | Electron Capture | No Data Available |
| Alpha Decay | No Data Available | ||
| 202 | 9.7 seconds | Alpha Decay | 78.00% |
| Electron Capture | 22.00% | ||
| 203 | 44 seconds | Alpha Decay | 66.00% |
| Electron Capture | 34.00% | ||
| 203m | 26.9 seconds | Alpha Decay | 75.00% |
| Electron Capture | 25.00% | ||
| 204 | 74.5 seconds | Alpha Decay | 72.40% |
| Electron Capture | 27.60% | ||
| 205 | 170 seconds | Alpha Decay | 24.60% |
| Electron Capture | 75.40% | ||
| 206 | 5.67 minutes | Alpha Decay | 62.00% |
| Electron Capture | 38.00% | ||
| 207 | 9.25 minutes | Electron Capture | 79.00% |
| Alpha Decay | 21.00% | ||
| 208 | 24.35 minutes | Alpha Decay | 62.00% |
| Electron Capture | 38.00% | ||
| 209 | 28.5 minutes | Electron Capture | 83.00% |
| Alpha Decay | 17.00% | ||
| 210 | 2.4 hours | Electron Capture | 4.00% |
| Alpha Decay | 96.00% | ||
| 211 | 14.6 hours | Electron Capture | 72.60% |
| Alpha Decay | 27.40% | ||
| 212 | 23.9 minutes | Alpha Decay | 100.00% |
| 213 | 19.5 milliseconds | Alpha Decay | 100.00% |
| 214 | 0.27 microseconds | Alpha Decay | 100.00% |
| 215 | 2.30 microseconds | Alpha Decay | 100.00% |
| 216 | 45 microseconds | Alpha Decay | 100.00% |
| 217 | 0.54 milliseconds | Alpha Decay | 100.00% |
| 218 | 35 milliseconds | Alpha Decay | 100.00% |
| 219 | 3.96 seconds | Alpha Decay | 100.00% |
| 220 | 55.6 seconds | Alpha Decay | 100.00% |
| 221 | 25 minutes | Beta-minus Decay | 78.00% |
| Alpha Decay | 22.00% | ||
| 222 | 3.8235 days | Alpha Decay | 100.00% |
| 223 | 24.3 minutes | Beta-minus Decay | 100.00% |
| 224 | 107 minutes | Beta-minus Decay | 100.00% |
| 225 | 4.66 minutes | Beta-minus Decay | 100.00% |
| 226 | 7.4 minutes | Beta-minus Decay | 100.00% |
| 227 | 20.8 seconds | Beta-minus Decay | 100.00% |
| 228 | 65 seconds | Beta-minus Decay | 100.00% |
| 229 | 12.0 seconds | Beta-minus Decay | 100.00% |
| 230 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
| 231 | > 300 nanoseconds | Beta-minus Decay | No Data Available |
This page is maintained by Steve Gagnon.