What is "lutetium"

Lutetium \Lu*te"ti*um\, n. (Chem.) A metallic element separated from ytterbium in 1907, by Urbain in Paris and by von Welsbach in Vienna. It is a member of the Lanthanide rare earth group. Symbol, Lu; atomic number 71; atomic weight 174.967 [C=12.011]. Previously spelled Lutecium.

n. A metallic chemical element (''symbol'' Lu) with an atomic number of 71.

n. a trivalent metallic element of the rare earth group; usually occurs in association with yttrium [syn: lutecium, Lu, atomic number 71]

Lutetium is a chemical element with symbol Lu and atomic number 71. It is a silvery white metal, which resists corrosion in dry, but not in moist air. It is the last element in the lanthanide series, and is traditionally counted among the rare earths. It is sometimes considered the first element of the 6th-period transition metals, although lanthanum is sometimes considered as such instead of lutetium.

Lutetium was independently discovered in 1907 by French scientist Georges Urbain, Austrian mineralogist Baron Carl Auer von Welsbach, and American chemist Charles James. All of these men found lutetium as an impurity in the mineral ytterbia, which was previously thought to consist entirely of ytterbium. The dispute on the priority of the discovery occurred shortly after, with Urbain and Welsbach accusing each other of publishing results influenced by the published research of the other; the naming honor went to Urbain, as he had published his results earlier. He chose the name lutecium for the new element, but in 1949 the spelling of element 71 was changed to lutetium. In 1909, the priority was finally granted to Urbain and his names were adopted as official ones; however, the name cassiopeium (or later cassiopium) for element 71 proposed by Welsbach was used by many German scientists until the 1950s.

Lutetium is not a particularly abundant element, though significantly more common than silver in the earth's crust; it has few specific uses. Lutetium-176 is a relatively abundant (2.5%) radioactive isotope with a half-life of about 38 billion years, and so used to determine the age of meteorites. Lutetium usually occurs in association with the element yttrium and is sometimes used in metal alloys and as a catalyst in various chemical reactions. Lu- DOTA-TATE is used for radionuclide therapy (see Nuclear medicine) on neuroendocrine tumours. Lutetium has the highest Brinell hardness of any lanthanide, at 890–1300 MPa.