Pm
Promethium-139m
Protons (Z)
61
Neutrons (N)
78
Mass number
139
Half-Life
180.0 ms
Abundance
---
Mass
138.917 u
Mass Excess
-77,312.0 keV
Spin
(11/2-)
Discovered
1975
Binding energy per nucleon
8,284 keV
Neutron separation energy
10,469 keV
Proton separation energy
2,584 keV
Decay Mode
Decay chain
- PmPromethium-139Z 61 · N 78180.0 ms
- γ100%
- β⁺100%
- β⁺100%
- β⁺100%
- EC100%