- Atomic Radius (Å)
Thulium is a chemical element with symbol Tm and atomic number 69. It is the thirteenth and antepenultimate (third-last) element in the lanthanide series. Like the other lanthanides, the most common oxidation state is +3, seen in its oxide, halides and other compounds.
69
Atomic Number
168.93 u
Atomic Mass
1818.15 K
Melting Point
2223 K
Boiling Point
9.32 g/cm³
Density
2.4 Å
Atomic Radius
1.9 Å
Covalent Radius
1.25
Electronegativity
6.18 eV
First Ionization Energy
99
Electron Affinity
6
Number of Shells
2, 8, 18, 31, 8, 2
Electron Shell Occupations
0.16 J/g
Specific Heat