La
Lanthanum is the namesake of the lanthanide series, used in camera lenses and catalysts.
Physical Properties
| Atomic Mass | 138.91 u |
| Density | 6.145 g/cm³ |
| Melting Point | 1193.0 K |
| Boiling Point | 3737.0 K |
| Appearance | Silvery-white metallic |
| State at Room Temp | Solid |
Chemical Properties
| Electronegativity | 1.1 (Pauling) |
| 1st Ionization Energy | 538.1 kJ/mol |
| Electron Affinity | 53.0 kJ/mol |
| Oxidation States | +2, +3 |
Atomic Properties
| Electron Configuration | [Xe] 5d1 6s2 |
| Atomic Radius | 187.0 pm |
| Covalent Radius | 207.0 pm |
| Van der Waals Radius | 240.0 pm |
Discovery
| Discovered By | Carl Gustaf Mosander |
| Discovery Year | 1839 |
| Location | Stockholm, Sweden |
| Named After | Greek 'lanthanein' meaning to lie hidden |
About Lanthanum
Lanthanum is a soft, ductile, silvery-white metal that tarnishes rapidly. It is found in rare earth minerals like monazite and bastnaesite. It has no biological role.
Uses & Applications
Camera and telescope lenses, catalytic cracking in petroleum, battery electrodes, and lighter flints.
Fun Fact
Lanthanum was 'hidden' inside cerium oxide for 36 years before separation -- fitting since its name means 'to lie hidden'.
Isotopes
| Mass Number | Abundance | Half-Life | Stable |
| 138 | 0.0009% | - | Yes |
| 139 | 0.9991% | - | Yes |
Electron Configuration
[Xe] 5d1 6s2