Europium is valued for light-emitting materials, including red-emitting phosphors and security features. It also absorbs neutrons effectively. Its applications show why a small amount of an element can matter: an added species can give a material a distinctive response to light or radiation.
FROM ELEMENT TO APPLICATION
AN ELEMENT IN CONTEXT
Why does a europium phosphor need excitation before it emits useful red light?
Europium-containing phosphor
FOLLOW THIS RELATIONSHIP
Place europium in a phosphor
Europium-containing optical centers occupy a compound or host material. Their environment differs from europium atoms in a macroscopic piece of metal.
Explore the model (optional)
Spatial model
INTERACTIVE 3D36 visible sites
Europium · an activator in a hostDrag to rotate · scroll or pinch to zoom
Phosphor host
An activator ion occupies a small fraction of sites in a host material. Select excitation to connect this arrangement to light emission.
What this representation means
Conceptual phosphor schematic, not a specific crystal structure, measured spectrum, or atomistic emission simulation. Color is an explanatory cue; host sites and concentration are illustrative.
Which change removes an essential part of this operating explanation?
Atomic identity, reference properties and structure models
INTERACTIVE 3D36 visible sites
Europium · an activator in a hostDrag to rotate · scroll or pinch to zoom
Phosphor host
An activator ion occupies a small fraction of sites in a host material. Select excitation to connect this arrangement to light emission.
What this representation means
Conceptual phosphor schematic, not a specific crystal structure, measured spectrum, or atomistic emission simulation. Color is an explanatory cue; host sites and concentration are illustrative.
A rare-earth separation becomes an optical signature
Eugène-Anatole Demarçay established europium in 1901 through careful separation of samarium-containing material. Its distinct optical behavior later became useful in phosphors and luminescent markers. A 2020 research demonstration used europium-containing materials in light-activated codes on banknote specimens. These events connect identification and application: characteristic light signals can reveal an element in a laboratory and carry designed information in a material.
1901
Europium separated
Demarçay distinguished europium from samarium-containing material.
2020
Optical-code demonstration
Researchers demonstrated europium-based luminescent codes on banknote specimens.
Europium occurs with other rare-earth elements in such as monazite and bastnaesite. It is dispersed among chemically related constituents rather than normally found as native metal. creates the separated europium compounds used in optical materials, connecting mineral chemistry to a very different visible application.
Europium compounds can emit distinctive light after excitation, but color depends on and host environment. Trivalent europium commonly supplies red in phosphors; this does not make every europium-containing material red. Luminescence releases previously supplied energy and should not be represented as continuous light produced without an energy source.
Each section links its supporting references. Descriptions and diagrams were authored for this atlas. Source checks completed. Source checks dated 2026-09-06.
CITE THIS PAGE
Family labels and the group-3 layout are teaching conventions. A table position does not establish an unknown bulk property. Electronic configurations refer to neutral atoms; ions and material environments require their own account.
Read each reference property together with its units, conditions and the reference information below.
Not yet recorded: electron affinity, second ionization energy, ground-state term symbol, van der waals radius, thermal conductivity, specific heat capacity, electrical resistivity, crystal structure, lattice parameter a, space group, abundance in seawater, abundance in the universe, annual production, supply-risk listing, hazard classification, biological role, cas registry number, pubchem cid, wikidata item. These families are declared and awaiting an ingestion run against the source each names; they are listed here rather than shown as empty rows.
Physical
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Phase at 20 °C
solid
293.15 K, 101.325 kPa
Melting point in K
1099 K
at standard pressure unless noted
Boiling point in K
1802 K
101.325 kPa
Density in g/cm³
5.24 g/cm³
solids and liquids at 293 K; gases at 273 K and 101.325 kPa
Atomic and electronic
Intended reference: Pauling electronegativity scale · Widely tabulated; original in The Nature of the Chemical Bond
Electronegativity in Pauling
1.2 Pauling
Pauling scale
First ionization energy in kJ/mol
547.1 kJ/mol
gas-phase neutral atom, ground state
Covalent radius in pm
198 pm
single-bond covalent radius
Common oxidation states
+2, +3
states met in ordinary compounds; not exhaustive
Occurrence and identity
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Abundance in the crust in mg/kg
2 mg/kg
upper continental crust, mass fraction
Has stable isotopes
Yesderived
Discovery year in CE
1901 CEderived
WHERE IT SITS AMONG ITS NEIGHBORS
Electronegativity across period 6
Eu 1.2 Pauling · Europium
Electronegativity across period 6. Exact values.
Cs
0.79
Ba
0.89
La
1.1
Ce
1.12
Pr
1.13
Nd
1.14
Sm
1.17
Eu
1.2
Gd
1.2
Tb
1.1
Dy
1.22
Ho
1.23
Er
1.24
Tm
1.25
Yb
1.1
Lu
1.27
Hf
1.3
Ta
1.5
W
2.36
Re
1.9
Os
2.2
Ir
2.2
Pt
2.28
Au
2.54
Hg
2
Tl
1.62
Pb
2.33
Bi
2.02
Po
2
At
2.2
The trend uses the same reference-property values as the periodic table. Elements with no recorded value are left out of the line rather than drawn at zero.
