Europium(III) oxide

Europium(III) oxide (Eu2O3), is a chemical compound of europium and oxygen. It is widely used as a red or blue phosphor in television sets and fluorescent lamps, and as an activator for yttrium-based phosphors. It is also an agent for the manufacture of fluorescent glass. Europium fluorescence is used in the anti-counterfeiting phosphors in Euro banknotes.

Europium oxide has two common structures: Monoclinic (mS30, space group C2/m, No. 12) and cubic (cI80, space group Ia$\overline{3}$, No. 206). The cubic structure is similar to that of manganese(III) oxide.

It may be formed by ignition of europium metal.

It can react with acids to form the corresponding europium(III) salts.