lutetiums

Lutetium is a chemical element with the symbol Lu and atomic number 71. It is a silvery-white metal and the heaviest and one of the least abundant lanthanides in the Earth's crust. In typical compounds it most often adopts the +3 oxidation state. Like other lanthanides, lutetium is resistant to corrosion but will gradually oxidize in air to form a surface oxide.

Occurrence and production are tied to rare earth mineral deposits. Lutetium is found in minerals such as monazite and gadolinite and is usually obtained as a byproduct of processing these rare earth ores. Industrial isolation involves complex separation and purification steps, followed by reduction of lutetium salts to the metal.

Isotopes of lutetium include Lu-175, which is stable, and Lu-176, a long-lived radioisotope present in natural lutetium. A reactor-produced nuclide, Lu-177, is widely used in medicine for targeted radiotherapy and is employed in radiopharmaceuticals such as Lutathera (177Lu-DOTATATE). Its dual beta and gamma emissions enable both therapy and imaging.

Applications of lutetium compounds are diverse. Lutetium oxide and lutetium-containing ceramics are used in specialty optics and phosphors. Lutetium aluminum garnet doped with cerium (LuAG:Ce) and lutetium oxyorthosilicate (LSO, Lu2SiO5:Ce) are important scintillators in radiation detectors and medical imaging. In chemical processing, lutetium-containing catalysts have been explored for hydrocarbon transformations, though they are not as widespread as some other rare earth catalysts.

The name lutetium derives from Lutetia, the ancient Roman name for Paris, reflecting its discovery in the early 20th century by Georges Urbain and his collaborators. The element is primarily of interest for specialized research, medical applications, and advanced materials.