Comparison of Tantalum and Osmium

Attribute	Osmium ×	Tantalum ×
Atomic mass (u)	190.2	180.9479
Standard state	Solid	Solid
Oxidation states	+3 +4	+5
Electron configuration	[Xe]6s²4f¹⁴5d⁶	[Xe]6s²4f¹⁴5d³
Atomic radius (van der waals) (pm)	216	217
Electronegativity (pauling scale)	2.2	1.5
Electron affinity (eV)	1.1	0.322
Ionization energy (eV)	8.7	7.89
Boiling point (K)	5285	5731
Melting point (K)	3306	3290
Density (g/cm³)	22.57	16.4
Atomic number	76	73
Group name	Transition metal	Transition metal
Discovered (year)	1803	1802
Symbol	Os	Ta