| General | |
|---|---|
| Symbol | 232Th |
| Names | thorium-232, 232Th, Th-232 |
| Protons (Z) | 90 |
| Neutrons (N) | 142 |
| Nuclide data | |
| Natural abundance | 99.98%[1] |
| Half-life (t1/2) | 1.4×1010 years[1] |
| Isotope mass | 232.0380536[2] Da |
| Spin | 0+ |
| Parent isotopes | 236U (α) 232Ac (β−) |
| Decay products | 228Ra |
| Decay modes | |
| Decay mode | Decay energy (MeV) |
| alpha decay | 4.0816[3] |
| Isotopes of thorium Complete table of nuclides | |
Thorium-232 (232
Th
) is the main naturally occurring isotope of thorium, with a relative abundance of 99.98%. It has a half life of 14 billion years, which makes it the longest-lived isotope of thorium. It decays by alpha decay to radium-228; its decay chain terminates at stable lead-208.
Thorium-232 is a fertile material; it can capture a neutron to form thorium-233, which subsequently undergoes two successive beta decays to uranium-233, which is fissile. As such, it has been used in the thorium fuel cycle in nuclear reactors; various prototype thorium-fueled reactors have been designed. However, as of 2024, thorium has not been used for commercial-scale nuclear power.
- ^ a b Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
- ^ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
- ^ National Nuclear Data Center. "NuDat 3.0 database". Brookhaven National Laboratory. Retrieved 19 Feb 2022.
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