61
Pm
145
Promethium
Element 61 · 145 u · f-block
lanthanide
The only radioactive lanthanide with no stable isotopes. Used in nuclear batteries and luminous paint.
Phase (STP)
Solid
Melting Point
1042 °C
Boiling Point
3000 °C
Density
7.26 g/cm³
Electronegativity
1.13
Atomic Radius
185 pm
Ionization Energy
540 kJ/mol
Electron Affinity
12 kJ/mol
Discovered
1945 · Jacob Marinsky
Electron Configuration
[Xe] 4f5 6s2
Electron Orbitals
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