- 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
Atomic Mass (u)
1818.15
Melting Point (K)
2223
Boiling Point (K)
9.32
Density (solid: g/cm³, gas: g/liter)
2.4
Atomic Radius (Å)
1.9
Covalent Radius (Å)
1.25
Electronegativity
6.18
First Ionization Energy (eV)
99
Electron Affinity
6
Number of Shells
2, 8, 18, 31, 8, 2
Electron Shell Occupations
0.16
Specific Heat (J/g)