Lanthanum
📷 In Your World
Lanthanum is a soft, silvery-white metal that is the first element in the lanthanide series. Its compounds are used to make high-quality camera and telescope lenses because they have a high refractive index and low dispersion. It is also a key component in the nickel-metal hydride (NiMH) batteries used in many hybrid cars.
📖 The Discovery Story
Lanthanum was discovered in 1839 by Swedish chemist Carl Gustaf Mosander. He was studying a sample of cerium nitrate and realized it contained another, previously unknown element. He named it "lanthanum" from the Ancient Greek word lanthanein, meaning "to lie hidden," because it had been hiding undetected within cerium ore.
📊 Properties at a Glance
| Phase at STP | Solid |
| Melting Point | 920 °C / 1688 °F |
| Boiling Point | 3464 °C / 6267 °F |
| Electron Configuration | [Xe] 5d¹6s² |
| Abundance in Earth's Crust | 0.0039% |
⚠️ Safety & Handling
Lanthanum metal is reactive and will tarnish quickly in air. It is soft enough to be cut with a knife. While the pure metal has low to moderate toxicity, its compounds should be handled with care as their effects are not fully understood.