Every red pixel on your TV screen owes its color to europium. This soft, silvery metal produces the purest red light of any known substance. It also quietly guards the money in your wallet — euro banknotes contain invisible europium markers that glow red under ultraviolet light.
Europium is the only chemical element named after an entire continent. French chemist Eugene-Anatole Demarcay isolated it in 1901. Among all the lanthanides, europium is the most reactive: a freshly cut surface tarnishes within minutes, and the powdered form can ignite spontaneously in air.
Europium is extremely rare in the Earth's crust — just 2 milligrams per kilogram of rock. That is 30 times less than cerium. Most of it comes from the minerals bastnaesite and monazite, primarily mined in China. To separate europium from other lanthanides, chemists exploit its unique ability to adopt the +2 oxidation state — something other rare earths simply cannot do.
Today, demand for europium keeps growing alongside the LED lighting and anti-counterfeiting industries. About 85% of the world's europium supply goes into phosphor production.
Metallic europium is highly reactive. It reacts vigorously with water, releasing hydrogen gas and forming europium hydroxide Eu(OH)3. The powdered form is pyrophoric and can ignite spontaneously in air at just 150 degrees Celsius. It must be stored in sealed containers under argon or submerged in mineral oil. Europium compounds are moderately toxic: prolonged inhalation of Eu2O3 dust can damage the lungs. Gloves and a respirator are mandatory when handling this metal.
Europium is the most reactive rare earth metal. A freshly cut surface tarnishes in just minutes, and at 150 degrees Celsius the powder bursts into bright flame. It must be stored under argon or submerged in mineral oil.
Europium is the only element named after a continent. There are elements named after countries (francium, polonium) and cities (hafnium, berkelium), but only europium honors an entire part of the world.
Every euro banknote contains a europium-based phosphor. Under an ultraviolet lamp it glows red, and each denomination has a unique pattern. Counterfeiting this protection is extraordinarily difficult.
Europium ions (Eu3+) emit red light with a quantum yield above 95%. That makes it the most efficient red phosphor in the world. This is why TVs and smartphones rely on europium for their red pixels.
Europium is one of the softest lanthanide metals — soft enough to cut with a kitchen knife. Its density of 5.24 grams per cubic centimeter is the lowest among all rare earth elements.
Cool europium below 90 Kelvin and it becomes an antiferromagnet. Its atomic magnetic moments line up in opposite directions — a rare behavior among metals that fascinates physicists.
| Isotope | Mass (u) | Abundance | Half-life | Decay |
|---|---|---|---|---|
151Eu | 150.919850 | 47.81% | stable | — |
153Eu | 152.921230 | 52.19% | stable | — |
Fractional crystallization of samarium