(Lutetia, ancient name for Paris, sometimes called cassiopeium by the Germans) In 1907,
Urbain described a process by which Marignac's ytterbium (1879) could be separated into
the two elements, ytterbium (neoytterbium) and lutetium. These elements were identical
with "aldebaranium" and "cassiopeium," independently discovered at
this time. The spelling of the element was changed from lutecium to lutetium in 1949.
Lutetium occurs in very small amounts in nearly all minerals containing yttrium, and is
present in monazite to the extent of about 0.003%, which is a commercial source. The pure
metal has been isolated only in recent years and is one of the most difficult to prepare.
It can be prepared by the reduction of anhydrous LuCl3 or LuF3 by an alkali or alkaline earth metal. The
metal is silvery white and relatively stable in air. While new techniques, including
ion-exchange reactions, have been developed to separate the various rare-earth elements,
lutetium is still the most costly of all rare earths. It is priced at about $75/g. 176Lu
occurs naturally (2.6%) with 175Lu (97.4%). It is radioactive with a half-life of about 3
x 1010 years. Stable
lutetium nuclides, which emit pure beta radiation after thermal neutron activation, can be
used as catalysts in cracking, alkylation, hydrogenation, and polymerization. Virtually no
other commercial uses have been found yet for lutetium. While lutetium, like other
rare-earth metals, is thought to have a low toxicity rating, it should be handled with
care until more information is available.