Eugène-Anatole Demarçay, a French chemist, discovered europium in 1896. Europium is primarily obtained through an ion exchange process from monazite, a mineral rich in rare earth elements. Europium is amongst the least abundant of the rare earth elements and is also the most reactive. It is about as hard as lead, quite ductile and rapidly oxidizes in air. Samples of the metal, even when coated with a protective layer of mineral oil, are rarely shiny and it readily ignites in air above 150°C.
Applications of Europium:
- Ceramics and Specialty Glass: Europium has been used to dope some types of glass to make lasers and it is also used as an agent in the manufacture of fluorescent glass.
- Phosphors: Europium oxide is widely used as a red phosphor in television sets and fluorescent lamps and as an activator for yttrium-based phosphors. Whereas trivalent europium gives red phosphors, the luminescence of divalent europium emits light on the blue side of the visible spectrum. These two europium phosphors, combined with yellow and green terbium phosphors give ‘white’ light. Combining the same three phosphors is one way to make trichromatic systems in TV and computer screens. This phosphor system is also used in helical fluorescent light bulbs.
- Energy: Europium is being studied for use in nuclear reactors for its ability to absorb neutrons.
- Other Uses: Europium is commonly included in trace element studies in geochemistry and petrology to understand the processes that form igneous rocks. It is also used as a phosphor in Euro banknotes to detect their production by counterfeiting.