Europium
Element Name: Europium
Atomic Number: 63
Atomic Mass: 151.964
Atomic Symbol: Eu
Melting Point: 822°C
Boiling Point: 1529°C
Eugene-Anatole Demarcay discovered europium in 1901 after doubting the purity of samarium samples. It is a bright silver-white metal that is soft and ductile. It has exceptionally low melting point and density for a lanthanide. It is the most reactive rare earth and will ignite in air. It will quickly oxidize in air. It has 30 isotopes, 2 of which are found in nature at relatively similar abundances. Europium has both divalent and trivalent forms, which causes it to sometimes displace other 2+ ions in common substances. The fluorescence of certain samples of fluorite is actually caused by small amounts of Eu2+.
Interesting Facts:
The Euro bank note has europium in it as an anti-forgery measure. This causes the notes to glow distinctively when placed under UV light. Europium is an excellent neutron absorber and sees used in control rods of nuclear reactors. Europium is naturally depleted and enriched in certain areas. This is a consequence of Europium’s two valid charge states; it sometimes can replace calcium (which also has a 2+ charge) in certain minerals. This is known as the Eu anomaly. This is not unique to the earth, as the moon also demonstrates this different. The darker portions of the moon (the lunar mare) are mostly basalt and are Eu negative while the white highlands are Eu positive.
Sources:
Europium is the rarest of the rare-earth elements (aside from promethium which does not occur in nature). It’s only found at 1.8 parts per million in the earth’s crust. Europium is not found in its elemental form in nature, but rather in minerals such as monazite, bastnaesite, xenotime, and loparite.
Industrial Uses:
Europium’s primary use has been in the phosphors of tube TVs and monitors. The distinctive red color of europium 3+ phosphors allowed TVs to become much brighter as red phosphors were always the most muted. The trivalent variant makes a vibrant red light, and the divalent variant makes a blue light; together these two make a white light which is what is used in fluorescent bulbs. It’s also used in fluorescent glass that has a persistent after-glow once there is no more light going through it.
References:
“Europium.”Chemicool Periodic Table. Chemicool.com, 16 Oct. 2012. Web. 26 July
2016.
“Europium Anomoly.” Wikipedia. Wikimedia Foundation, n.d. Web. 23 June 2016.
“Europium.” Wikipedia. Wikimedia Foundation, n.d. Web. 26 July 2016.
“Facts About Europium.” Livescience. Livescience.com, 15 July 2013. Web. 26 July 2016.