  Articles - Uses of europium
Various internet sources reported the theft of
460 kilograms of europium oxide from the Kyrgyz Chemical-Mechanical Plant in Central Asia in January of 2003.
Apparently, this europium oxide powder had been acquired in the past for intended use in the manufacture of
control rods for nuclear reactions.
The theft sounded a bit puzzling to me. When I searched the web, however, I found sites that
compare rare earth elements (REEs) to precious metals like gold and platinum and batches of rare earths were offered on
various metal auction sites. Europium (Eu) is one of those rare earth elements.
Rare earth elements are indeed very expensive, partly because it is very expensive to extract and
concentrate them from their ores. Of all the REEs, europium is reported to be the most expensive.
The thieves might therefore have seen the europium oxide as an investment opportunity, but shares, gold and diamonds –
or even a smart piece of real estate - would probably be a lot easier to sell. Unlike with gold and platinum
(precious metals), you cannot create jewelry from europium and the average citizen has no use for it. Europium oxide
cannot be used to make explosives or nuclear devices either. So what is europium? What is it good for?
Europium is a metal as soft as lead. It can have the divalent
oxidation state (mainly in rocks) but in the p,T and redox conditions of the earth's surface,
it strongly prefers to be trivalent.
That makes the metal highly reactive and, as a result, toxic, corrosive, irritant and particularly flammable. It readily
reacts with oxygen and water if not protected and handled carefully (stored under oil, for instance, and kept away
from heat).
The metal's oxide is therefore much more stable. Note: This does not mean that anyone who happens to have
europium metal in his possession should simply expose it to air.
Wrapped europium metal in various stages of oxidation:
Europium has many technological uses.
Europium complexes are used to distinguish genuine bank notes from falsified ones
and have applications in analytical chemistry as well. Examples of other applications of Eu involve CRT and flat
screens for color TVs and computers, and laser equipment.
Europium absorbs neutrons quite well, hence its use in control rods in, for example, uranium plants in
Russia and Ukraine.
One newer development focuses on the commercial application of this particular (spent) europium (Eu-152, 154 and 155)
as a much-needed gamma source for sterilization purposes (against microorganisms). That would take care of this
nuclear-waste storage problem as well.
Note that europium's naturally occurring isotopes - Eu-151 and 153 - are not radioactive. However, REEs
and actinides - the latter are radioactive - often occur together in nature because of their chemical similarities.
P.S.
See also this
blog post about rare earth elements and their use in for instance green technologies.
(Did you know that the motor of a Toyota Prius contains 1 to 2 kilograms of neodymium?)
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