Protactinium-231 (Pa-231)
Identity
- Protons
- 91
- Neutrons
- 140
- Mass number
- 231
- Mass
- 231.0 ± 1.9 u
- Mass excess
- 33.424 MeV
- Spin
- 3/2-*
Stability
Half-life: 3.27 × 10⁴ years
Natural occurrence
100.00 % of protactinium
Decays to
- alpha 100.0 % Ac-227
- spontaneous fission 3.0e-10 %