Comparison of Niobium and Iridium

Attribute	Iridium ×	Niobium ×
Atomic mass (u)	192.22	92.90637
Standard state	Solid	Solid
Oxidation states	+3 +4	+3 +5
Electron configuration	[Xe]6s²4f¹⁴5d⁷	[Kr]5s¹4d⁴
Atomic radius (van der waals) (pm)	202	207
Electronegativity (pauling scale)	2.2	1.6
Electron affinity (eV)	1.565	0.893
Ionization energy (eV)	9.1	6.759
Boiling point (K)	4701	5017
Melting point (K)	2719	2750
Density (g/cm³)	22.42	8.57
Atomic number	77	41
Group name	Transition metal	Transition metal
Discovered (year)	1803	1801
Symbol	Ir	Nb