Bismuth-209
| General | |
|---|---|
| Symbol | 209Bi |
| Names | bismuth-209 |
| Protons (Z) | 83 |
| Neutrons (N) | 126 |
| Nuclide data | |
| Natural abundance | 100% |
| Half-life (t1/2) | 2.01×1019 years |
| Isotope mass | 208.980399 Da |
| Spin | 9/2− |
| Excess energy | −18258.461±2.4 keV |
| Nuclear binding energy | 7847.987±1.7 keV |
| Parent isotopes | 209Pb (β−) 209Po (β+) 213At (α) |
| Decay products | 205Tl |
| Decay modes | |
| Decay mode | Decay energy (MeV) |
| Alpha emission | 3.1373 |
| Isotopes of bismuth Complete table of nuclides | |
Bismuth-209 (209Bi) is an isotope of bismuth with the longest known half-life of any nuclide that undergoes α-decay (alpha decay); the decay product is thallium-205. It has 83 protons and a magic number of 126 neutrons, and naturally-occurring bismuth consists entirely of this isotope.