Europium (Eu)
Element 63 · Lanthanide · atomic mass 151.96 u · f-block, period 6
Electron shells: 2, 8, 18, 25, 8, 2
Europium is the most reactive rare earth and the best red phosphor known. Its glow under UV is used as an anti-counterfeiting mark in euro banknotes.
Hold a euro note under UV light and the red glow you see is europium.
- Atomic number
- 63
- Atomic mass
- 151.96 u
- Electron configuration
- [Xe] 6s² 4f⁷
- Group · period · block
- f-block · 6 · f
- Oxidation states
- +2, +3
- Electronegativity
- Not measured
- Melting point
- 822 °C
- Boiling point
- 1,529 °C
- Density
- 5.24 g/cm³
- State at 20 °C
- Solid
- Appearance
- Soft, silvery metal
- Discovered
- Eugène-Anatole Demarçay, 1901
63 protons, and 63 electrons when neutral
IUPAC standard atomic weight
Shown in the strip below the table
What Europium is used for
- Red and blue phosphors in displays and LEDs
- Banknote anti-counterfeiting markers
- Fluorescent lamps
- Nuclear control rods
Atomic structure of Europium
A neutral europium atom has 63 protons and 63 electrons. Its most common isotope carries about 89 neutrons, which is where the mass number 152 comes from. Change the neutron count and you have a different isotope of europium; change the proton count and you have a different element entirely.
Those electrons fill shells from the inside out: 2, 8, 18, 25, 8, 2. In orbital notation that is [Xe] 6s² 4f⁷. As a f-block element its valence count is variable, which is why it can form compounds in several oxidation states.
3D electron orbitals
See where Europium's electrons actually are — a cloud of 26,000 points sampled from the probability density |ψ|², not a cartoon of a lobe.
Where Europium sits in the periodic table
The first f-block row, elements 57-71. Chemically near-identical to each other and hard to separate, yet essential to magnets, lasers and phosphors.
- One proton lighter: Samarium.
- One proton heavier: Gadolinium.
Discovery and naming
Europium was discovered by Eugène-Anatole Demarçay in 1901. Its name comes from The continent of Europe.
Keep exploring
Atomic weight from IUPAC/CIAAW; physical properties from PubChem (US National Library of Medicine). Values that have never been measured are shown as “not measured” rather than estimated.
Related Calculators
Frequently Asked Questions
What is the atomic mass of Europium?
The standard atomic weight of Europium is 151.96 u, as published by IUPAC's Commission on Isotopic Abundances and Atomic Weights.
How many protons, neutrons and electrons does Europium have?
Europium has 63 protons, because the atomic number is the proton count and that is what makes an atom Europium at all. A neutral Europium atom has the same number of electrons, 63. The neutron count varies by isotope; the most common one has about 89, since 152 − 63 = 89.
What is the electron configuration of Europium?
The electron configuration of Europium is [Xe] 6s² 4f⁷. Its electrons are arranged 2, 8, 18, 25, 8, 2 across 6 shells.
Is Europium a metal?
Yes. Europium is classified as a lanthanide, on the metallic side of the table.
What group and period is Europium in?
Europium sits in the f-block strip below the main table, in period 6, among the lanthanides. Elements in that strip are not given a group number in the standard 18-column layout.
What is the charge of Europium?
Europium most commonly forms a 3+ or 2+ ion. Like most transition metals it has several accessible oxidation states, so the charge depends on the compound.
What is the melting point of Europium?
Europium melts at 822 °C and boils at 1,529 °C. That puts it in the solids at everyday temperatures.
What is Europium used for?
Red and blue phosphors in displays and LEDs, Banknote anti-counterfeiting markers, Fluorescent lamps, Nuclear control rods. Europium is the most reactive rare earth and the best red phosphor known.
Who discovered Europium, and where does its name come from?
Europium (Eu) was discovered by Eugène-Anatole Demarçay in 1901. The name comes from The continent of Europe.