Lu - Lutetium

Properties

Lutetium is a silvery white metal belonging to the lanthanoid group of the periodic table. Lutetium has the highest atomic weight, highest density, highest melting point and is the hardest of all the rare earth elements. Also along with thulium it is the rarest of the rare earth elements, being the 60th most abundant element within the Earths crust. The metal is also corrosion resistant.

History

Lutetium was discovered in 1907 by the French Chemist, George Urbain. The discovery of lutetium was the last in a sequence of elements found within a sample of yttrium. Yttrium was the first in this sequence and from it erbium and terbium were extracted in 1843. From erbium, holmium was extracted in 1878 and thulium in 1879 and finally lutetium in 1907. Urbain decide to call his new element lutetium, which was derived from the ancient name for Paris, ‘Lutetia’. Two other contemporary chemists were also on the verge of discovering this element independently of Urbain: Karl Auer of Germany and Charles James of the USA. Auer decided to name it cassiopeium, and this is the name by which the metal is known in Germany. A pure sample of lutetium was not produced until 1953.

Sources

Lutetium occurs in very small amounts alongside yttrium. It is recovered, by ion-exchange routines, in small quantities from yttrium-concentrates. It can also be prepared by the reduction of anhydrous LuCl3 or LuF3 by an alkali or alkaline earth metal. The pure metal has only been isolated relatively recently.

Uses

Due to the difficulty in obtaining large quantities of lutetium, it has few commercial applications. It is used in single crystal scintillators and in detectors in positron emission tomography. It has also recently found use as a pure beta emitter: stable lutetium nuclides emit pure beta radiation after thermal neutron activation, so it is used as a catalyst in cracking, alkylation, hydrogenation, and polymerization.