Comparison of Molybdenum and Ruthenium

Attribute	Ruthenium ×	Molybdenum ×
Atomic mass (u)	101.1	95.95
Standard state	Solid	Solid
Oxidation states	+3	+6
Electron configuration	[Kr]5s¹4d⁷	[Kr]5s¹4d⁵
Atomic radius (van der waals) (pm)	207	209
Electronegativity (pauling scale)	2.2	2.16
Electron affinity (eV)	1.05	0.746
Ionization energy (eV)	7.361	7.092
Boiling point (K)	4423	4912
Melting point (K)	2607	2896
Density (g/cm³)	12.1	10.2
Atomic number	44	42
Group name	Transition metal	Transition metal
Discovered (year)	1827	1778
Symbol	Ru	Mo