Comparison of Dysprosium and Thulium

Attribute	Thulium ×	Dysprosium ×
Standard state	Solid	Solid
Electron configuration	[Xe]6s²4f¹³	[Xe]6s²4f¹⁰
Atomic mass (u)	168.93422	162.5
Electronegativity (pauling scale)	1.25	1.22
Oxidation states	+3	+3
Ionization energy (eV)	6.184	5.939
Atomic radius (van der waals) (pm)	227	229
Boiling point (K)	2223	2840
Melting point (K)	1818	1685
Density (g/cm³)	9.32	8.55
Atomic number	69	66
Group name	Lanthanide	Lanthanide
Discovered (year)	1879	1886
Symbol	Tm	Dy