Lanthanum, with the chemical symbol La and atomic number 57, was discovered in 1839 by Swedish chemist Carl Gustaf Mosander. He isolated it from cerium salts and named it after the Greek word "lanthanein," meaning "to lie hidden," reflecting the challenges of separating it from other lanthanides.
On Earth, lanthanum is relatively abundant and is found in minerals such as monazite and bastnäsite, constituting about 0.004% of the Earth's crust. Lanthanum has a silver-white color and is a soft, malleable metal.
Lanthanum finds exciting applications in technology, particularly in the production of catalysts for oil refining and in nickel-metal hydride batteries. Lanthanum oxide is also used in the glass and ceramic industry to enhance optical properties.