Element 57 · Lanthanide (Rare Earth)
Lanthanum
The first of the rare earth lanthanides — used in catalytic cracking of petroleum and rechargeable battery anodes.
Element Facts
SYMBOL
La
ATOMIC NO.
57
ATOMIC WEIGHT
138.91
CATEGORY
Lanthanide (Rare Earth)
PERIOD
Period 6
GROUP
Group 3
Origins
Lanthanum was discovered in 1839 by Carl Gustaf Mosander by extracting an impurity from cerium nitrate. Named from the Greek “lanthanein” meaning to lie hidden, as it had escaped detection in earlier cerium research. It gave its name to the entire lanthanide series. In the early 20th century, lanthanum oxide was used in high-refractive-index optical glass for camera lenses. Lanthanum-nickel alloy became important for hydrogen storage in nickel-metal hydride (NiMH) batteries used in hybrid vehicles.
Key Properties
Lanthanum is element 57, the namesake of the lanthanide series. It is a soft silvery rare earth metal that tarnishes rapidly in air. Despite the term "rare earth," lanthanum is more abundant than lead in the Earth's crust — the "rare" name reflects historical extraction difficulty, not actual rarity.
Modern Applications
Petroleum cracking catalysts (FCC catalysts) for converting crude oil into petrol and diesel. Nickel-metal hydride (NiMH) battery negative electrodes. High-refractive-index camera lenses. Carbon arc electrodes for cinema projectors and welding.
At the Yard
Why QuickStop Metals doesn’t buy Lanthanum:
Lanthanum and other rare earths exist in commercial products only as alloying elements at small percentages. Recovery requires complex chemical extraction not available at general scrap yards. Items containing rare earths typically flow into general non-ferrous or steel scrap streams where the rare earth content is unrecoverable in standard processing.
Market Value
Lanthanum oxide trades at approximately £1–3/kg — as the most abundant rare earth it is also one of the cheapest. Not a scrap yard metal, sourced mainly from Chinese bastnasite processing.