Comparison of Lanthanum and Actinium

Attribute	Actinium ×	Lanthanum ×
Atomic mass (u)	227.02775	138.9055
Standard state	Solid	Solid
Oxidation states	+3	+3
Electron configuration	[Rn]7s²6d¹	[Xe]6s²5d¹
Atomic radius (van der waals) (pm)	260	240
Electronegativity (pauling scale)	1.1	1.1
Electron affinity (eV)	-	0.5
Ionization energy (eV)	5.17	5.577
Boiling point (K)	3471	3737
Melting point (K)	1324	1191
Density (g/cm³)	10.07	6.15
Atomic number	89	57
Group name	Actinide	Lanthanide
Symbol	Ac	La
Discovered (year)	1899	1839