Europium
Europium is a soft, reactive lanthanide first separated out in 1901 and named after the continent of Europe. It's the most chemically reactive of the rare-earth metals, and it plays an outsized role in how we see color on screens and how we spot counterfeit money.
- Group · Period
- — · 6
- At room temp
- solid
- Melts at
- 1095 K
- Density
- 5.24 g/cm³
- Discovered
- 1901
Uses
Europium’s defining use is as a phosphor. Compounds containing europium ions glow strongly and in very specific colors when hit by ultraviolet light or an electric current — europium(III) compounds give a deep red, while europium(II) compounds give a blue or blue-green. That range made europium central to color television and computer monitor screens for decades, and it’s still used in energy-efficient fluorescent and LED lighting to help produce a more natural-looking white light.
That same fluorescence is put to a very different use in currency: euro banknotes incorporate europium-based fluorescent markings as one layer of their anti-counterfeiting protection, since the glow is difficult to reproduce without the right materials.
History
Europium was identified in 1901 by French chemist Eugène-Anatole Demarçay, who separated it from samples of samarium and gadolinium that earlier chemists had assumed were pure. Like many lanthanides, it had been hiding, mixed in with its close neighbors, in rare-earth minerals that took decades of careful chemical separation to fully untangle. Demarçay named the new element after the continent of Europe, continuing a naming tradition that also gave us elements like americium and francium tied to places.
Fun facts
- Euro banknotes contain europium compounds that glow under ultraviolet light, one of the security features used to spot counterfeits.
- Europium is the most reactive of all the lanthanide elements, tarnishing quickly in air.
- Europium compounds produce both the red and blue colors used in many phosphor-based screens and lighting, depending on how the europium ion is bonded.
Frequently asked questions
Why do euro banknotes glow under UV light?
The banknotes use fluorescent security markings, and europium compounds are among the materials that produce this glow, since europium ions are excellent at absorbing UV light and re-emitting it as sharp, bright visible colors. It's one of several anti-counterfeiting features, alongside things like watermarks and security threads.
What is europium used for besides banknotes?
Its main industrial role is as a phosphor — a substance that glows when excited by electricity or UV light. Europium compounds have long supplied the red phosphor in television and display screens and the blue phosphor in some energy-efficient lighting, because different europium compounds emit sharply different colors.
Why is europium so much more reactive than other lanthanides?
Europium's electron structure makes it easier for it to lose electrons and react with oxygen and moisture than most of its lanthanide neighbors, which is why samples tarnish quickly in air and why europium metal is typically stored away from air, often under oil or inert gas.
Compounds
3 notable compounds containing Eu
- EuCl2halide
Europium(II) chloride
One of the few lanthanide dihalides that is genuinely stable, reflecting europium's unusually accessible +2 oxidation state and its chemical resemblance to the alkaline-earth metals.
Used for: Research reagent for europium(II) luminescent materials
- EuCl3halide
Europium(III) chloride
A pale yellow, water-soluble europium salt in which europium holds its common +3 state, typically handled in the laboratory as its hydrate.
Used for: Laboratory precursor for europium luminescent and coordination compounds
- Eu2O3oxide
Europium(III) oxide
A pale pink to white rare-earth oxide that is the most common commercial source of europium and serves as the parent compound for europium-activated phosphors.
Used for: Base material for red phosphors in older CRT and plasma displays
Isotopes
39 known isotopes
Swipe to see all columns →
| Isotope | Natural abundance | Half-life | Decay mode | Mass excess | Binding energy / nucleon | Decay width |
|---|---|---|---|---|---|---|
| Eu-151 | 47.81% | 1.7E+18 Y | Alpha decay | -74,653.1 keV | 8,239.3 keV | 8.50 × 10-42 eV |
| Eu-153 stable | 52.19% | Stable | — | -73,367.47 keV | 8,228.7 keV | — |
Show all 39 isotopes
| Eu-130 | — | 0.90 ms | Proton emission (100%) | -33,513 keV | 7,950 keV | 5.07 × 10-13 eV |
| Eu-131 | — | 17.8 ms | Proton emission (89%), Electron capture / beta-plus decay (11%) | -39,464 keV | 7,996 keV | 2.56 × 10-14 eV |
| Eu-132 | — | — | Proton emission (0%), Electron capture / beta-plus decay | -42,200 keV | 8,018 keV | — |
| Eu-134 | — | 0.5 s | Electron capture / beta-plus decay (100%), ECP (0%) | -49,800 keV | 8,075 keV | 9.12 × 10-16 eV |
| Eu-135 | — | 1.5 s | Electron capture / beta-plus decay (100%), ECP | -54,148 keV | 8,107 keV | 3.04 × 10-16 eV |
| Eu-136 | — | 3.3 s | Electron capture / beta-plus decay (100%), Beta-plus, proton emission (0.09%) | -56,244 keV | 8,122 keV | 1.38 × 10-16 eV |
| Eu-137 | — | 11 s | Electron capture / beta-plus decay (100%) | -60,145.9 keV | 8,150.57 keV | 4.15 × 10-17 eV |
| Eu-138 | — | 12.1 s | Electron capture / beta-plus decay (100%) | -61,749.68 keV | 8,161.62 keV | 3.77 × 10-17 eV |
| Eu-139 | — | 17.9 s | Electron capture / beta-plus decay (100%) | -65,398.05 keV | 8,187.22 keV | 2.55 × 10-17 eV |
| Eu-140 | — | 1.51 s | Electron capture / beta-plus decay (100%) | -66,985.95 keV | 8,197.73 keV | 3.02 × 10-16 eV |
| Eu-141 | — | 40.7 s | Electron capture / beta-plus decay (100%) | -69,925.65 keV | 8,217.69 keV | 1.12 × 10-17 eV |
| Eu-142 | — | 2.34 s | Electron capture / beta-plus decay (100%) | -71,308.93 keV | 8,226.4 keV | 1.95 × 10-16 eV |
| Eu-143 | — | 2.59 m | Electron capture / beta-plus decay (100%) | -74,241.31 keV | 8,245.82 keV | 2.94 × 10-18 eV |
| Eu-144 | — | 10.2 s | Electron capture / beta-plus decay (100%) | -75,619.18 keV | 8,254.17 keV | 4.47 × 10-17 eV |
| Eu-145 | — | 5.93 d | Electron capture / beta-plus decay (100%) | -77,991.52 keV | 8,269.27 keV | 8.90 × 10-22 eV |
| Eu-146 | — | 4.61 d | Electron capture / beta-plus decay (100%) | -77,117.6 keV | 8,261.93 keV | 1.15 × 10-21 eV |
| Eu-147 | — | 24.1 d | Electron capture (99.9978%), Alpha decay (0.0022%) | -77,544.61 keV | 8,263.54 keV | 2.19 × 10-22 eV |
| Eu-148 | — | 54.5 d | Electron capture / beta-plus decay (100%), Alpha decay (9.4e-7%) | -76,297.48 keV | 8,253.82 keV | 9.69 × 10-23 eV |
| Eu-149 | — | 93.1 d | Electron capture (100%) | -76,441.32 keV | 8,253.56 keV | 5.67 × 10-23 eV |
| Eu-150 | — | 36.9 Y | Electron capture / beta-plus decay (100%) | -74,792.37 keV | 8,241.35 keV | 3.92 × 10-25 eV |
| Eu-152 | — | 13.517 Y | Electron capture / beta-plus decay (72.08%), Beta-minus decay (27.92%) | -72,888.5 keV | 8,226.59 keV | 1.07 × 10-24 eV |
| Eu-154 | — | 8.601 Y | Beta-minus decay (99.982%), Electron capture / beta-plus decay (0.018%) | -71,738.37 keV | 8,217.1 keV | 1.68 × 10-24 eV |
| Eu-155 | — | 4.753 Y | Beta-minus decay (100%) | -71,818.34 keV | 8,216.68 keV | 3.04 × 10-24 eV |
| Eu-156 | — | 15.19 d | Beta-minus decay (100%) | -70,082.84 keV | 8,204.62 keV | 3.48 × 10-22 eV |
| Eu-157 | — | 15.18 h | Beta-minus decay (100%) | -69,459.13 keV | 8,199.8 keV | 8.35 × 10-21 eV |
| Eu-158 | — | 45.9 m | Beta-minus decay (100%) | -67,270.46 keV | 8,185.13 keV | 1.66 × 10-19 eV |
| Eu-159 | — | 18.1 m | Beta-minus decay (100%) | -66,043.39 keV | 8,176.7 keV | 4.20 × 10-19 eV |
| Eu-160 | — | 42.6 s | Beta-minus decay (100%) | -63,493.45 keV | 8,160.1 keV | 1.07 × 10-17 eV |
| Eu-161 | — | 26 s | Beta-minus decay (100%) | -61,791.6 keV | 8,148.98 keV | 1.75 × 10-17 eV |
| Eu-162 | — | 10.6 s | Beta-minus decay (100%) | -58,722.94 keV | 8,129.56 keV | 4.30 × 10-17 eV |
| Eu-163 | — | 7.7 s | Beta-minus decay (100%) | -56,573.82 keV | 8,116.02 keV | 5.93 × 10-17 eV |
| Eu-164 | — | 4.15 s | Beta-minus decay (100%) | -53,232.15 keV | 8,095.37 keV | 1.10 × 10-16 eV |
| Eu-165 | — | 2.3 s | Beta-minus decay (100%) | -50,729.1 keV | 8,080.05 keV | 1.98 × 10-16 eV |
| Eu-166 | — | 1.7 s | Beta-minus decay (100%), Beta-minus, neutron emission | -46,749 keV | 8,056 keV | 2.68 × 10-16 eV |
| Eu-167 | — | 1.3 s | Beta-minus decay (100%), Beta-minus, neutron emission | -43,770 keV | 8,038 keV | 3.51 × 10-16 eV |
| Eu-168 | — | 0.20 s | Beta-minus decay (100%), Beta-minus, neutron emission | -39,250 keV | 8,012 keV | 2.28 × 10-15 eV |
| Eu-169 | — | — | Beta-minus decay (100%), Beta-minus, neutron emission | -35,660 keV | 7,991 keV | — |