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57
La
138.91
Lanthanum
Lanthanides · Group 3 · Period 6–7 (f)
Atomic properties
| Atomic number | 57 |
|---|---|
| Symbol | La |
| Standard atomic weight | 138.91 |
| Classification | Lanthanides |
| Group | f-block series |
| Period | 6 |
| Block | f-block (lanthanide) |
| Electron configuration | [Xe] 5d1 6s2 |
| Electronegativity (Pauling) | 1.10 |
| Common oxidation states | +3 |
Physical properties
| Phase at 20 °C | Solid |
|---|---|
| Density | 6.162 g/cm³ |
| Melting point | 920 °C |
| Boiling point | 3464 °C |
| Discovered | 1839 |
| CAS number | — |