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 considered the first element of the 6th-period transition metals and the last element in the lanthanide series, and is traditionally counted among the rare earths.
L 7090 (OTTO) Lutetium sputtering target, diam. x thickness 76.2 mm × 3 mm, 99% Cas 7439-94-3 - used as a phosphor in LED light bulbs.