Europium
Symbol |
Name |
Atomic Number |
Atomic Weight |
Group Number |
Eu |
Europium |
63 |
151.96 |
|
Standard Sate: solid at 298 K
Color: silvery white
Europium ignites in air at about 150 to 180�C. Europium is about as hard as lead and is quite ductile. It is the most reactive of the rare earth metals, quickly oxidising in air. It resembles calcium in its reaction with water. It is used in television screens to produce a red colour.
(Eu), chemical element, rare-earth metal of transition Group IIIb of
the periodic table; it is the least dense, softest, and most volatile
member of the lanthanide series. The element was discovered (1896)
by Eug�ne-Anatole Demar�ay and named for Europe. One of the
least abundant rare earths, it occurs in minute amounts in many
rare-earth minerals such as monazite and also in the products of
nuclear fission. Europium is usually separated by reducing it to the
+2 oxidation state and precipitating it with sulfate ions. The primary
use of europium has been for research purposes. Because it readily
absorbs thermal neutrons, it may prove to be of use in nuclear-reactor
control rods. It has been used as a phosphor activator, as a
component of certain electronic materials, and as an agent in the
manufacture of fluorescent glass. The metal has been prepared by
electrolysis of the fused halides and by reduction of its oxide by
lanthanum metal followed by distillation of the europium metal. It
quickly reacts in air, oxygen, and water. Both of its naturally
occurring isotopes are stable: europium-151 (47.8 percent) and
europium-153 (52.2 percent).
In its predominant trivalent state, europium behaves as a typical rare
earth, forming a series of generally pale pink salts. The Eu3+ ion is
paramagnetic because of the presence of unpaired electrons.
Europium possesses the most easily produced and stablest +2
oxidation state of the rare earths. Trivalent europium solutions can
be reduced by zinc metal and hydrochloric acid to give Eu2+ in
solution; the ion is stable in dilute hydrochloric acid if oxygen from the
air is excluded. A series of white to pale yellow or green europium(II)
salts are known, such as europium(II) sulfate, chloride, hydroxide, and
carbonate. The divalent halides may be prepared by hydrogen
reduction of the anhydrous trivalent halides. atomic number 63 atomic
weight 151.965 melting point 822 C boiling point 1,527 C specific
gravity 5.244 (25 C) valence 2, 3 electronic config. 2-8-18-25-8-2 or
(Xe)4f 75d06s2
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