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69
Tm
168.93
Thulium
Lanthanides · Group 15 · Period 6–7 (f)
Atomic properties
| Atomic number | 69 |
|---|---|
| Symbol | Tm |
| Standard atomic weight | 168.93 |
| Classification | Lanthanides |
| Group | f-block series |
| Period | 6 |
| Block | f-block (lanthanide) |
| Electron configuration | [Xe] 4f13 6s2 |
| Electronegativity (Pauling) | 1.25 |
| Common oxidation states | +3 |
Physical properties
| Phase at 20 °C | Solid |
|---|---|
| Density | 9.32 g/cm³ |
| Melting point | 1545 °C |
| Boiling point | 1950 °C |
| Discovered | 1879 |
| CAS number | — |