Pm
Promethium
Z = 61 · Lanthanide · 145.0 u
Nuclear Engineering Significance
All isotopes are radioactive. Pm-147 (t₁/₂ = 2.62 y) is a fission product that decays to Sm-147, which captures neutrons to produce the strong poison Sm-149. Promethium is the link in the samarium poisoning chain and affects long-term reactivity.
Basic properties
- Atomic number (Z)
- 61
- Standard atomic mass
- 145.0 u
- Category
- Lanthanide
Isotopes & cross-section data
| Isotope | Mass (A) | Half-life | ZAID | Libraries |
|---|---|---|---|---|
| Pm-147 | 147 | 2.6234 y | .80c.71c | |
| Pm-149 | 149 | 53.08 h | .80c.71c |