ELEMENTLE

Element 63 · Lanthanide

Europium

Period 6

Europium is a chemical element with symbol Eu and atomic number 63. It was isolated in 1901 and is named after the continent of Europe. It is a moderately hard, silvery metal which readily oxidizes in air and water.

Three reasons Europium stands out

  1. 1

    Used as red phosphor in TVs, glows red under UV light.

  2. 2

    It is printed invisibly on euro banknotes as an anti-counterfeiting measure that only fluoresces under ultraviolet light.

  3. 3

    It has the strongest fluorescence of any element, making it invaluable in security and display technology.

The element behind a red pixel

Europium ions emit intense, sharply defined red and blue light when excited. Red phosphors made color television convincing, and modern security inks use the same optical fingerprints. Europium is also unusually willing among lanthanides to form a +2 ion, giving its chemistry a distinctive branch.

Europium at a glance
Atomic number / protons63
SymbolEu
Family (Elementle)Lanthanide
Classification (PubChem)Lanthanide
Period6
GroupLanthanide / actinide series
Atomic mass (u)151.964
Standard stateSolid
Electron configuration[Xe]6s2 4f7
Reported oxidation states+3, +2
Electronegativity (Pauling)Not available
Atomic radius (pm)233
First ionization energy (eV)5.670
Electron affinity (eV)Not available
Density (g/cm³)5.24
Melting point1095 K (821.85 °C)
Boiling point1802 K (1,528.85 °C)
Discovery (PubChem)1901

Values are reference data, not a specification for every temperature, pressure, or allotrope. Unknown properties are left unavailable. Superheavy-element predictions remain uncertain.

Sources & further reading

PubChem: Europium · Europium on Wikipedia

The introduction and original editorial story are adapted from Wikipedia contributors via Periodic-Table-JSON. Element descriptions and their adaptations are available under CC BY-SA 3.0. Numerical attributes use the PubChem periodic-table dataset, retrieved September 22, 2026.