Europium (Eu)
lanthanideSolid
Standard Atomic Weight
151.964 uElectron configuration
[Xe] 6s2 4f7Melting point
821.85 °CBoiling point
1528.85 °CDensity
5240 kg/m³Oxidation states
0, +2, +3Electronegativity (Pauling)
N/AIonization energy (1st)
5.670385 eVDiscovery year
1896Atomic radius
185 pmDetails
Europium is a lanthanide rare-earth metal with atomic number 63. It is chemically notable for the relative stability of both Eu³⁺ and Eu²⁺, a contrast to most lanthanides, which are dominated by the +3 state. This redox flexibility controls much of its mineral behavior and its optical technology. Europium is best known for intense, narrow luminescence from Eu³⁺ and Eu²⁺ ions in solid hosts, especially in phosphors and security materials.
As with other rare-earth metals, except for lanthanum, europium ignites in air at about 150 to 180°C. Europium is about as hard as lead and is quite ductile. It is the most reactive of the rare-earth metals, quickly oxidizing in air. It resembles calcium in its reaction with water. Bastnasite and monazite are the principal ores containing europium.
The name derives from the continent of Europe. It was separated from the mineral samaria in magnesium- samarium nitrate by the French chemist Eugène-Anatole Demarçay in 1896. It was also first isolated by Demarçay in 1901.
Europium was discovered by Eugène-Antole Demarçay, a French chemist, in 1896. Demarçay suspected that samples of a recently discovered element, samarium, were contaminated with an unknown element. He was able to produce reasonably pure europium in 1901. Today, europium is primarily obtained through an ion exchange process from monazite sand ((Ce, La, Th, Nd, Y)PO4), a material rich in rare earth elements.
Named after Europe. In 1890 Boisbaudran obtained basic fractions from samarium-gadolinium concentrates which had spark spectral lines not accounted for by samarium or gadolinium. These lines subsequently have been shown to belong to europium. The discovery of europium is generally credited to Demarcay, who separated the rare earth in reasonably pure form in 1901. The pure metal was not isolated until recent years.
Pure europium is a soft, silvery metal that tarnishes rapidly in air and can darken as oxide and hydroxide layers form. It is among the more reactive lanthanide metals and is usually stored under inert gas or oil to limit oxidation.
Europium is used chiefly as an activator ion in luminescent materials. Eu³⁺ gives red emission in many oxide and vanadate phosphors, while Eu²⁺ can give blue, green, or other emissions depending on the host lattice. These phosphors have been important in color television tubes, fluorescent lamps, light-emitting diodes, displays, and anti-counterfeiting inks. Europium-doped materials are also used as optical probes in analytical assays, taking advantage of sharp emission lines and long-lived excited states.
Europium is the most reactive of the rare earth elements. There are no commercial applications for europium metal, although it has been used to dope some types of plastics to make lasers. Since it is a good absorber of neutrons, europium is being studied for use in nuclear reactors.
Europium oxide (Eu2O3), one of europium's compounds, is widely used as a red phosphor in television sets and as an activator for yttrium-based phosphors.
Europium-doped plastic has been used as a laser material. With the development of ion-exchange techniques and special processes, the cost of the metal has been greatly reduced in recent years.
Isotopes in Geochronology
For more than 40 years, weapons-grade plutonium was manufactured by the Krasnoyarsk Mining and Chemical Combine in the now closed town of Krasnoyarsk Krai, Russia, using single-pass uranium-graphite production reactors [447] Z. G. Gritchenko, Y. V. Kuznetsov, V. K. Legin, V. N. Strukov. Radiochemistry44, 199 (2002).. Water from the Yenisei River was used for heat removal from the reactor core. Radioactively contaminated water was discharged into the Yenisei River and was a primary source of contamination of bottom sediments and floodland for hundreds of kilometers down gradient from the Krasnoyarsk Mining and Chemical Combine. In 2002, radioactive contamination of the bottom sediments and floodlands was composed primarily of 137Cs, 152Eu, 154Eu, and 60Co [447] Z. G. Gritchenko, Y. V. Kuznetsov, V. K. Legin, V. N. Strukov. Radiochemistry44, 199 (2002).. The decrease in the isotope-amount ratio n(154Eu)/n(152Eu) down the depth profiles (Fig. IUPAC.63.1) enables one to determine the age of bottom sediments and floodlands of the Yenisei River and calculate their average formation rates [447] Z. G. Gritchenko, Y. V. Kuznetsov, V. K. Legin, V. N. Strukov. Radiochemistry44, 199 (2002)..
Isotopes in Industry
Europium isotopes have been used in nuclear-control applications because they are good neutron absorbers [448] C. R. Hammond. “The elements”, in CRC Handbook of Chemistry and Physics, C. Press, Taylor & Francis Group (1998).. 152Eu (with a half-life of 13.5 years), which is produced by 151Eu via the neutron capture reaction 151Eu (n, γ) 152Eu, and 154Eu (with a half-life of 8.59 years) are used as reference sources for calibration in gamma ray spectroscopy (Fig. IUPAC.63.2) [449] K. V. Vimalnatha, M. K. Dasb, M. Ananthakrishnana, N. Ramamoorthy. Appl. Radiat. Isot.62, 17 (2005)..
Isotopes Used as a Source of Radioactive Isotope(s)
Reactions on 153Eu can produce the therapeutic radionuclide 153Sm (with a half-life of about 1.9 days) via fast neutron irradiation 153Eu (n, p) 153Sm [451] M. Al-Abyad, I. Spahn, S. Sudár, M. Morsy, M. N. H. Comsan, J. Csikai, S. M. Qaim, H. H. Coenen. Appl. Radiat. Isot.64, 717 (2006)..
Europium chemistry is dominated by ionic compounds of Eu³⁺, but Eu²⁺ compounds are unusually accessible for a lanthanide and resemble alkaline-earth compounds in size and behavior. Europium(III) oxide, Eu₂O₃, is a common source and phosphor precursor. Europium(II) oxide, EuO, is a ferromagnetic semiconductor studied in solid-state physics. Halides such as europium(III) chloride, EuCl₃, and europium(II) chloride, EuCl₂, illustrate the two main oxidation states. Complexes of Eu³⁺ with organic ligands are widely used for luminescence studies.
See more information at the Europium compound page.
Europium metal presents a fire and chemical hazard because finely divided material can oxidize readily and reacts with moisture and acids to release hydrogen, H₂. Soluble europium salts are not known to have a biological role and should be treated as toxicologically incompletely characterized heavy-metal compounds. Dusts and aerosols are the main practical exposure concern in laboratories and phosphor manufacture. Natural europium is only weakly radioactive through long-lived ¹⁵¹Eu.
Europium occurs dispersed in rare-earth minerals rather than as native metal. It is typically present in monazite, bastnäsite, xenotime, and related deposits, and it follows other trivalent rare earths during weathering and sediment transport. Its ability to exist as Eu²⁺ under reducing geological conditions produces europium anomalies in rocks and minerals, which are useful tracers of magmatic and crustal processes. It has no known essential biological function.
Europium is produced as a separated rare earth from mineral concentrates, not mined as a primary element. Its separation is helped by the distinctive Eu²⁺/Eu³⁺ redox chemistry, but high purity still requires solvent extraction or ion-exchange processing. Demand has historically been tied to red phosphors for lamps and displays; changes in lighting technology and improved phosphor efficiency have reduced some consumption. Recycling from spent fluorescent lamps and display phosphors is technically possible, but collection, contamination, and changing waste streams limit broad recovery. Supply is linked to the wider rare-earth industry and to by-product recovery decisions.
Europium has been identified spectroscopically in the sun and certain stars. Seventeen isotopes are now recognized. Europium isotopes are good neutron absorbers and are being studied for use in nuclear control applications.
Europium is a rare element in the universe. Its stable isotopes are made mainly by neutron-capture nucleosynthesis, with the rapid r-process especially important. Because its spectral lines can be measured in old stars, europium is often used by astronomers as a tracer of r-process enrichment. In planetary materials it is lithophile and usually remains in oxide and silicate phases rather than metallic cores.
- Europium is one of the few lanthanides that commonly forms stable divalent compounds.
- Eu²⁺ can substitute for Ca²⁺ or Sr²⁺ in many phosphor host lattices.
- Europium anomalies help identify plagioclase fractionation in igneous rocks.
- The red emission of Eu³⁺ is extremely narrow compared with many organic dyes.
- EuO becomes ferromagnetic at low temperature.
Images
Properties
Physical
- Atomic radius (empirical)
- 185 pm Compare Atomic radius (empirical) of all elements →
- Covalent radius
- 198 pm Compare Covalent radius of all elements →
- Van der Waals radius
- 233 pm Compare Van der Waals radius of all elements →
- Density
- 5240 kg/m³ Compare Density of all elements →
- Molar volume
- 0.0289 L/mol
- Phase at STP
- Solid Compare Phase at STP of all elements →
- Melting point
- 821.85 °C Compare Melting point of all elements →
- Boiling point
- 1528.85 °C Compare Boiling point of all elements →
- Thermal conductivity
- 13.9 W/(m·K) Compare Thermal conductivity of all elements →
- Specific heat capacity
- 0.182 J/(g·K) Compare Specific heat capacity of all elements →
- Molar heat capacity
- 27.66 J/(mol·K) Compare Molar heat capacity of all elements →
- Crystal structure
- Body-centered cubic Compare Crystal structure of all elements →
Chemical
- Electron affinity
- 0.116 eV
- Ionization energy (1st)
- 5.670385 eV Compare Ionization energy (1st) of all elements →
- Ionization energy (2nd)
- 11.240039 eV Compare Ionization energy (2nd) of all elements →
- Ionization energy (3rd)
- 24.840086 eV Compare Ionization energy (3rd) of all elements →
- Ionization energy (4th)
- 42.940148 eV Compare Ionization energy (4th) of all elements →
- Ionization energy (5th)
- 63.200218 eV Compare Ionization energy (5th) of all elements →
- Oxidation states
- 0, +2, +3 Compare Oxidation states of all elements →
- Valence electrons
- 3 Compare Valence electrons of all elements →
- Electron configuration
- [Xe] 6s2 4f7
Thermodynamic
- Heat of fusion
- 0.09535161 eV Compare Heat of fusion of all elements →
- Heat of vaporization
- 1.824118 eV Compare Heat of vaporization of all elements →
- Heat of sublimation
- 1.886304 eV
- Heat of atomization
- 1.886304 eV
- Atomization enthalpy
- 1.838628 eV
Nuclear
- Protons
- 63 Compare Protons of all elements →
- Neutrons
- 88 Compare Neutrons of all elements →
- Known isotopes
- 41 Compare Known isotopes of all elements →
- Stable isotopes
- 0 Compare Stable isotopes of all elements →
- Most stable isotope
- Eu-151
- Discovery year
- 1896
Abundance
- Abundance (Earth's crust)
- 2 mg/kg Compare Abundance (Earth's crust) of all elements →
- Abundance (ocean)
- 1.3 × 10−7 mg/L Compare Abundance (ocean) of all elements →
Crystal Structure
- Lattice constant a
- 461 pm
Electronic Structure
- Electrons per shell
- 2, 8, 18, 25, 8, 2 Compare Electrons per shell of all elements →
Identifiers
- CAS number
- 7440-53-1 Compare CAS number of all elements →
- Term symbol
- 8S°7/2
- InChI
- InChI=1S/Eu
- InChI Key
- OGPBJKLSAFTDLK-UHFFFAOYSA-N
Electron Configuration Measured
Eu: 4f⁷ 6s²[Xe] 4f⁷ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f⁷ 6s²Atomic model
Isotopes change neutron count, mass, and stability — not the electron configuration of a neutral atom.
Schematic atomic model, not to scale.
Atomic Fingerprint
Emission / Absorption Spectrum
Isotope Distribution
No stable isotopes.
| Mass number | Atomic mass (u) | Natural abundance | Half-life |
|---|---|---|---|
| 153 Radioactive | 152.921238 ± 0.0000018 | 52.1900% | 550 Py |
| 134 Radioactive | 133.9464 ± 0.00032 | N/A | 500 ms |
| 169 Radioactive | 168.961717 ± 0.000537 | N/A | 420 ms |
| 133 Radioactive | 132.94929 ± 0.00032 | N/A | 200 ms |
| 168 Radioactive | 167.957863 ± 0.000429 | N/A | 200 ms |
Phase / State
Reason: 796.9 °C below melting point (821.85 °C)
Schematic, not to scale
Phase transition points
Transition energies
Energy required to melt 1 mol at melting point
Energy required to vaporize 1 mol at boiling point
Energy required to sublime 1 mol at sublimation point
Density
At standard conditions
At standard conditions
Atomic Spectra
Showing 10 of 63. Sorted by ion charge (ascending).
Lines Holdings ?
| Ion | Charge | Total lines | Transition probabilities | Level designations |
|---|---|---|---|---|
| Eu I | 0 | 350 | 152 | 343 |
| Eu II | +1 | 218 | 13 | 13 |
| Eu III | +2 | 229 | 0 | 0 |
Levels Holdings ?
| Ion | Charge | Levels |
|---|---|---|
| Eu I | 0 | 592 |
| Eu II | +1 | 163 |
| Eu III | +2 | 118 |
| Eu IV | +3 | 13 |
| Eu V | +4 | 2 |
| Eu VI | +5 | 2 |
| Eu VII | +6 | 2 |
| Eu VIII | +7 | 2 |
| Eu IX | +8 | 2 |
| Eu X | +9 | 2 |
Ionic Radii
| Charge | Coordination | Spin | Radius |
|---|---|---|---|
| +2 | 6 | N/A | 117 pm |
| +2 | 7 | N/A | 120 pm |
| +2 | 8 | N/A | 125 pm |
| +2 | 9 | N/A | 130 pm |
| +2 | 10 | N/A | 135 pm |
| +3 | 6 | N/A | 94.69999999999999 pm |
| +3 | 7 | N/A | 101 pm |
| +3 | 8 | N/A | 106.60000000000001 pm |
| +3 | 9 | N/A | 112.00000000000001 pm |
Compounds
Isotopes (5)
| Mass number | Atomic mass (u) | Natural abundance | Half-life | Decay mode | |
|---|---|---|---|---|---|
| 153 Radioactive | 152.921238 ± 0.0000018 | 52.1900% ± 0.0600% | 550 Py | IS =52.19±0.6% | |
| 134 Radioactive | 133.9464 ± 0.00032 | N/A | 500 ms | β+ =100%β+p =? | |
| 169 Radioactive | 168.961717 ± 0.000537 | N/A | 420 ms | β- ? | |
| 133 Radioactive | 132.94929 ± 0.00032 | N/A | 200 ms | β+ ?β+p ? | |
| 168 Radioactive | 167.957863 ± 0.000429 | N/A | 200 ms | β- =100%β-n ? |
Extended Properties
Covalent Radii (Extended)
- Covalent radius (Pyykkö)
- 168 pm
- Covalent radius (Pyykkö, double)
- 134 pm
Van der Waals Radii
- Alvarez
- 287 pm
- UFF
- 349.3 pm
- MM3
- 294 pm
Atomic & Metallic Radii
- Atomic radius (Rahm)
- 280 pm
Numbering Scales
- Mendeleev
- 25
- Pettifor
- 18
- Glawe
- 17
Electronegativity Scales
- Ghosh
- 0
- Miedema
- 3
- Gunnarsson–Lundqvist
- 3
- Robles–Bartolotti
- 2
Polarizability & Dispersion
- Dipole polarizability
- 184 a.u.
- Dipole polarizability (unc.)
- 20 a.u.
- C₆ (Gould–Bučko)
- 2940 Ha·Bohr6
Miedema Parameters
- Miedema molar volume
- 19.97 cm3/mol
- Miedema electron density
- 2
Supply Risk & Economics
- Production concentration
- 97
- Relative supply risk
- 10
- Reserve distribution
- 50
- Political stability (top producer)
- 24
- Political stability (top reserve)
- 24
Phase Transitions & Allotropes
| Melting point | 1095.15 K |
| Boiling point | 1802.15 K |
Oxidation State Categories
Advanced Reference Data
Screening Constants (13)
| n | Orbital | σ |
|---|---|---|
| 1 | s | 1.2391 |
| 2 | p | 4.282 |
| 2 | s | 16.5292 |
| 3 | d | 13.7472 |
| 3 | p | 19.716 |
| 3 | s | 20.1318 |
| 4 | d | 34.0592 |
| 4 | f | 38.68 |
| 4 | p | 31.1252 |
| 4 | s | 30.132 |
Crystal Radii Detail (9)
| Charge | CN | Spin | rcrystal (pm) | Origin |
|---|---|---|---|---|
| 2 | VI | 131 | ||
| 2 | VII | 134 | ||
| 2 | VIII | 139 | ||
| 2 | IX | 144 | ||
| 2 | X | 149 | ||
| 3 | VI | 108.7 | from r^3 vs V plots, | |
| 3 | VII | 115 | ||
| 3 | VIII | 120.6 | from r^3 vs V plots, | |
| 3 | IX | 126 | from r^3 vs V plots, |
Isotope Decay Modes (63)
| Isotope | Mode | Intensity |
|---|---|---|
| 130 | p | 100% |
| 130 | B+ | — |
| 130 | B+p | — |
| 131 | p | 89% |
| 131 | B+ | — |
| 131 | B+p | — |
| 132 | B+ | — |
| 132 | B+p | — |
| 132 | p | 0% |
| 133 | B+ | — |
X‑ray Scattering Factors (514)
| Energy (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0.18583 |
| 10.1617 | — | 0.19489 |
| 10.3261 | — | 0.20439 |
| 10.4931 | — | 0.21435 |
| 10.6628 | — | 0.22479 |
| 10.8353 | — | 0.23529 |
| 11.0106 | — | 0.24598 |
| 11.1886 | — | 0.25716 |
| 11.3696 | — | 0.26817 |
| 11.5535 | — | 0.27854 |
Additional Data
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
2.0 milligrams per kilogram
References (1)
- [5] Europium https://education.jlab.org/itselemental/ele063.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
1.3×10-7 milligrams per liter
References (1)
- [5] Europium https://education.jlab.org/itselemental/ele063.html
Sources
Sources of this element.
Europium has been identified spectroscopically in the sun and certain stars. Seventeen isotopes are now recognized. Europium isotopes are good neutron absorbers and are being studied for use in nuclear control applications.
References (1)
- [6] Europium https://periodic.lanl.gov/63.shtml
Production
Production of this element (from raw materials or other compounds containing the element).
Europium is now prepared by mixing Eu2O3 with a 10%-excess of lanthanum metal and heating the mixture in a tantalum crucible under high vacuum. The element is collected as a silvery-white metallic deposit on the walls of the crucible.
References (1)
- [6] Europium https://periodic.lanl.gov/63.shtml
References
(9)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
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The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.
The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database
This section provides all form of data related to element Europium.
The element property data was retrieved from publications.