This metal hid so well that scientists named it after the Greek word for "hidden." Swedish chemist Carl Mosander spent years searching for it inside cerium minerals. In 1839 he finally pulled lanthanum out of hiding. Today this soft, silvery metal leads an entire family of 15 elements called the lanthanides.
Despite the label "rare earth," lanthanum is anything but rare. There is more of it in the Earth's crust than silver or mercury. Without lanthanum, oil refineries would grind to a halt, camera lenses would blur, and hybrid cars would lose their batteries.
Lanthanum is a quiet workhorse of modern industry. Every year it helps refine billions of barrels of crude oil into gasoline. Its oxide makes optical glass remarkably clear. And a lanthanum-nickel alloy absorbs hydrogen like a sponge — powering the batteries in the Toyota Prius.
China produces over 60% of the world's lanthanum supply. Demand keeps climbing as hydrogen energy and electric vehicles expand. This once-hidden element has become an essential ingredient in 21st-century technology.
Powdered lanthanum is pyrophoric — it can ignite on its own at around 450 °C. Shavings may catch fire just from friction during cutting. The sneaky part: lanthanum compounds accumulate in the liver over time and can trigger granulomatosis (tissue inflammation). Working with lanthanum powder demands an inert atmosphere (argon or nitrogen). Bulk metal is safer, but prolonged skin contact may cause irritation.
The name "lanthanum" comes from the Greek word for "to hide." The element stayed hidden inside cerite minerals for 36 years until Mosander isolated it in 1839.
Every Toyota Prius hybrid contains about 10 kg of lanthanum. The alloy LaNi₅ absorbs hydrogen at 400 times its own metal volume — a sponge for hydrogen gas.
Lanthanum oxide has a refractive index of 1.95 — one of the highest among oxides. That is why lanthanum glass produces sharp images without color distortion.
Lanthanum-based catalysts process billions of barrels of oil every year. Without them, gasoline at the pump would cost significantly more.
Lanthanum is the father of a whole family. The 15 elements from lanthanum to lutetium are called lanthanides, and all share similar chemical behavior.
Lighter flints contain mischmetal — an alloy with about 25% lanthanum. The spark appears because this metal ignites easily from friction.
| Isotope | Mass (u) | Abundance | Half-life | Decay |
|---|---|---|---|---|
138La☢ | 137.907112 | 0.09% | 1.02×10¹¹ years | EC/β− |
139La | 138.906353 | 99.91% | stable | — |
Separation from cerium oxide