Europium

Europium is a chemical element with the symbol Eu and atomic number 63. It is named after the continent Europe. It is a moderately hard, silvery metal which readily oxidizes in air and water. Being a typical member of the lanthanide series, europium usually assumes the oxidation state +3, but the oxidation state +2 is also common: all europium compounds with oxidation state +2 are slightly reducing. Europium has no significant biological role and is relatively non-toxic compared to other heavy metals. Most applications of europium exploit the phosphorescence of europium compounds.
Symbol: Eu
Electron configuration: Xe 4f7 6s2
Melting point: 826 °C
Atomic number: 63
Discovered: 1901
Atomic mass: 151.964 ± 0.001 u