Comparison of Germanium and Promethium

Attribute	Promethium ×	Germanium ×
Atomic mass (u)	144.91276	72.63
Standard state	Solid	Solid
Oxidation states	+3	+2 +4
Electron configuration	[Xe]6s²4f⁵	[Ar]4s²3d¹⁰4p²
Atomic radius (van der waals) (pm)	236	211
Electronegativity (pauling scale)	-	2.01
Electron affinity (eV)	-	1.35
Ionization energy (eV)	5.55	7.9
Boiling point (K)	3273	3106
Melting point (K)	1315	1211.4
Density (g/cm³)	7.26	5.323
Atomic number	61	32
Group name	Lanthanide	Metalloid
Symbol	Pm	Ge
Discovered (year)	1945	1886