Appearance and Characteristics
Harmful effects:
Europium is considered to be mildly toxic. The metal dust is considered to be a fire and explosion hazard.
Characteristics:
Europium is a soft, ductile, silvery-white metal that instantly oxidizes in air. It is the most reactive of the rare earth metals and ignites in air at temperatures in excess of 150 oC to 180 oC. In water it reacts in a similar way to calcium, producing europium hydroxide and hydrogen gas. Unlike most other rare earth metals, europium can form stable compounds in the divalent state, Eu2+ (europous) as well as the usual trivalent state, Eu3+ (europic).
Uses of Europium
Europium oxide (europia) is widely used as a doping agent in phosphors in television sets and computer monitors: valency three europium produces a red radiance and valency two europium produces a blue radiance. When both valencies are combined a white light is produced which is used in compact fluorescent bulbs.
Europium is also used in phosphors in anti-forgery marks on Euro bank notes. Europium isotopes are good neutron absorbers and are used in nuclear reactor control rods.