lutetium

A silvery-white rare-earth element that is exceptionally difficult to separate from the other rare-earth elements, used in nuclear technology. Atomic number 71; atomic weight 174.97; melting point 1,663°C; boiling point 3,402°C; specific gravity 9.841 (at 25°C); valence 3. cross-reference: Periodic Table.

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.

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

a trivalent metallic element of the rare earth group; usually occurs in association with yttrium