Lanthano

Part of speech: noun

Definitions

1. A rare chemical element of the lanthanide series characterized by atomic number 57, used in various high-tech applications
2. Referring to a metallic element mostly found in rare earth minerals, often utilized in alloys and phosphors
3. Denoting a substance that occurs naturally in minerals and is significant in multiple industrial processes and technologies

Etymology: In 1839, the Swedish chemist Carl Gustaf Mosander was separating samples of cerium, a metal recovered from ore out of the Bastnäs mine. He found that his cerium samples contained a second substance that stayed hidden until he separated it out. He named it from the Greek "lanthanein," meaning "to lie hidden," a fitting name for an element that had been concealed inside cerium. The "-um" ending follows the convention for metallic elements, as in "platinum" and "potassium." The stem "lanthano-" appears in the names of the series of related elements that share its properties, which is why the family is called the lanthanides. The metal itself was not isolated in pure form until decades later, so Mosander named a substance that chemists could only identify indirectly for most of the nineteenth century.