Characteristics: Gray, ductile, highly reactive metal. Attacked by dilute and concentrated mineral acids and by alkalies. Readily oxidizes in moist air at room temperature. It has four allotropic forms. It is the second most reactive rare-earth metal. Cerium forms alloys with other lanthanides, it also forms a nonmetal with hydrogen, as well as carbides and intermetallic compounds. Decomposes in water; nontoxic.
Derivation: Chemical processing and separation of ores.
Hazard: May ignite on heating to 300 oF (148.9 oC). Strong reducing agent.