Europium

The red glow of old color televisions, and part of the hidden glow that protects euro banknotes from counterfeiters.

At a glance

Symbol: Eu
Atomic number: 63
Average atomic mass: 151.96
Group: none; it sits in the lanthanide row below the table
Period: 6
Family: lanthanide
Electron configuration: [Xe] 4f⁷ 6s²
Electronegativity: not measured
Common ions: Eu³⁺ and Eu²⁺

On the table

Period 6, in the lanthanide row set below the main table. The other lanthanides are tinted, and every cell opens its own article.

Electrons and bonding

Like the other lanthanides, it gives up three electrons to form the Eu³⁺ ion in most of its compounds.

Properties

State at 25 °C: solid
What it looks like: soft, silvery metal that tarnishes quickly; the most reactive lanthanide
Melting point: 822 °C
Boiling point: 1529 °C
Density: 5.24 g/cm³

Where it is found

One of the less common rare earths, found in bastnäsite and monazite, mostly mined in China.

Discovery and name

Eugène-Anatole Demarçay separated it in 1901 after noticing unexplained lines in the spectra of samarium samples, and named it after Europe.

What it is used for

Europium phosphors glow red and blue in fluorescent lamps, LEDs and old tube televisions, whose red dots contained europium. Europium compounds that glow under ultraviolet light are used as security marks, including on euro banknotes.

In compounds

Eu₂O₃europium oxide, red phosphorEuCl₃europium chlorideEuSeuropium sulfide