Lanthanum (La)
Lanthanum (La) is element 57 of the periodic table, a lanthanide in period 6, in the f-block. Its standard atomic weight is 138.90547, so one mole of lanthanum atoms has a mass of 138.90547 g. At room temperature it is a solid; it melts at 917.85 °C and boils at 3463.85 °C.
| Atomic number | 57 |
|---|---|
| Symbol | La |
| Standard atomic weight | 138.90547 |
| Molar mass | 138.90547 g/mol |
| Category | Lanthanide |
| Group | f-block (lanthanide series) |
| Period | 6 |
| Block | f-block |
| Electron configuration | [Xe] 6s2 5d1 |
| Oxidation states | +3 |
| Electronegativity (Pauling) | 1.1 |
| Atomic radius (van der Waals) | 240 pm |
| First ionisation energy | 5.577 eV (538.1 kJ/mol) |
| Electron affinity | 0.5 eV |
| State at room temperature | Solid |
| Melting point | 1191 K (917.85 °C) |
| Boiling point | 3737 K (3463.85 °C) |
| Density | 6.15 g/cm³ |
| Discovered | 1839 |
Lanthanides
Ce · CeriumPr · PraseodymiumNd · NeodymiumPm · PromethiumSm · SamariumEu · EuropiumGd · GadoliniumTb · TerbiumDy · DysprosiumHo · HolmiumEr · ErbiumTm · ThuliumYb · Ytterbium
Calculate with Lanthanum
Atomic weight: IUPAC CIAAW standard atomic weight. Other properties: PubChem (U.S. National Library of Medicine, public domain). Values such as melting point and radius depend on how they were measured; check a data book for precise work.