Comparison of Hafnium and Iridium

Attribute	Iridium ×	Hafnium ×
Standard state	Solid	Solid
Electron affinity (eV)	1.565	-
Electron configuration	[Xe]6s²4f¹⁴5d⁷	[Xe]6s²4f¹⁴5d²
Atomic mass (u)	192.22	178.49
Electronegativity (pauling scale)	2.2	1.3
Oxidation states	+3 +4	+4
Ionization energy (eV)	9.1	6.825
Atomic radius (van der waals) (pm)	202	212
Boiling point (K)	4701	4876
Melting point (K)	2719	2506
Density (g/cm³)	22.42	13.3
Atomic number	77	72
Group name	Transition metal	Transition metal
Discovered (year)	1803	1923
Symbol	Ir	Hf