Comparison of Niobium and Thorium

Attribute	Thorium ×	Niobium ×
Atomic mass (u)	232.038	92.90637
Standard state	Solid	Solid
Oxidation states	+4	+3 +5
Electron configuration	[Rn]7s²6d²	[Kr]5s¹4d⁴
Atomic radius (van der waals) (pm)	237	207
Electronegativity (pauling scale)	1.3	1.6
Electron affinity (eV)	-	0.893
Ionization energy (eV)	6.08	6.759
Boiling point (K)	5061	5017
Melting point (K)	2023	2750
Density (g/cm³)	11.72	8.57
Atomic number	90	41
Group name	Actinide	Transition metal
Symbol	Th	Nb
Discovered (year)	1828	1801