Cerium

Cerium, chemical element, symbol Ce; for physical constants see Periodic Table. A malleable metal, cerium is the most abundant of the rare-earth metals. Cerium was discovered in 1803 by Jons Berzelius and Wilhelm van Hisinger. It is found in various minerals monazite, being the most important source. Cerium and its compounds are used for decolorizing and polishing glass, in incandescent gas mantles, in carbon-arc lighting, and as catalysts.