Thulium |
| Symbol | Tm |
|---|---|
| Latin name | Thulium |
| Atomic number | 69 |
| Period | 6 |
| Element category | Inner transition elements |
| Relative atomic mass | 168.93421 |
| Group | III.B |
| Electronegativity | 1.2 |
| Oxidation numbers | 2, 3 |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f13 5d0 6s2 |
| Density [g/cm3] | 9.318 |
| State | Solid |
| Melting point [°C] | 1545 |
| Boiling point [°C] | 1947 |
| Atomic radius [pm] | 222 |
| Thermal conductivity [W m-1K-1] | 16.8 |
| Heat capacity [J K-1g-1] | 0.16 |
| Discovery | 1879 |
| Vickers hardness [MPa] | 520 |
| Brinell hardness [MPa] | 471 |
| Young's modulus [GPa] | 74 |
| Electrical conductivity [S m-1] | 1.4 · 106 |
| Shear modulus [GPa] | 31 |
| 1.st ionization energy [eV] | 6.1843 |
| 2.nd ionization energy [eV] | 12.054 |
| 3.rd ionization energy [eV] | 26.367 |
| Stable isotopes | 1 |
| Unstable isotopes | 17 |