Europium was discovered just over one hundred years ago, in 1896, when the French chemist, Eugne-Antole Demaray was investigating the newly discovered element of samarium. His samarium samples were contaminated, and on further investigation he found the contamination was an unknown element. He was able to produce pure europium by 1901. Today, europium is obtained from the mineral monazite. He named it after the continent of Europe.
Europium is very reactive; in fact, it is the most reactive of any of the rare earth metals. It is a member of the lanthanide family. The lanthanides are soft silvery metals, whose name means "hidden". They are very much alike and hard to distinguish from each other. They are members of the rare earth metal group, but many of them are not rare at all. Cerium is more common on earth than Copper. The least common lanthanide is Thulium and it is more common than silver. The lanthanides were discovered in the first half of the Twentieth Century.
The lanthanides have strong refractory effects and are thus used in light equipment and in lenses. They are also useful in lasers, CDs, and as colorants. Their emissions make the color in color television. They also have strong magnetic qualities and can run miniature motors. In this usage the lanthanides have become very common in technology. You also find lanthanides in electron microscopes and superconductors. Samarium is used to make the carbon lights that are in use in the motion picture industry, and are therefore responsible for the movies we see. They also make up the flint for cigarette lighters.
Europium has an atomic number of 63 and its symbol is Eu. Its atomic weight is 151.964 and it melts at 1095 K (822C or 1512F). Its boiling point is 1802 K (1529C or 2784F and its density is 5.24 grams per cubic centimeter. It has two stable isotopes.
There is little commercial use for europium, but it has been added to some plastics and in making lasers. It absorbs neutrons and is being studied to see if it can be used this role in nuclear reactors. One of europium's compounds, europium oxide, is used as a red phosphor in color televisions. It also acts as an activator of yttrium-based phosphors.
Europium is in use as a homeopathic remedy. It can be used to treat eye problems, especially iridocyclitis, and problems with the piriform muscle, the kidneys, and the liver. The mental state of a person needing the homeopathic remedy europium metallicum is one of duality between self-assured and insecure.