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Lutetium

Lutetium

Gist

Lutetium (Lu) is the element with atomic number 71, a rare earth metal that is silvery-white, hard, dense, and expensive. It is found in trace amounts in minerals like monazite and is used as a catalyst in the petroleum industry for processes like polymerization and alkylation. Lutetium-177 is a radioactive isotope used in targeted cancer therapies, such as in the treatment of prostate cancer.

Lutetium, outside of scientific research, is primarily used in the medical, petroleum, and geological industries. In medicine, it is used in cancer research, and geologically it is used to date meteorites. In petroleum, it is used to help crack hydrocarbons.

Lutetium (Lu) is the element with atomic number 71, a rare earth metal that is silvery-white, hard, dense, and expensive. It is found in trace amounts in minerals like monazite and is used as a catalyst in the petroleum industry for processes like polymerization and alkylation. Lutetium-177 is a radioactive isotope used in targeted cancer therapies, such as in the treatment of prostate cancer.

Summary

Lutetium is a chemical element; it has symbol Lu and atomic number 71. It is a silvery white metal, which resists corrosion in dry air, but not in moist air. Lutetium is the last element in the lanthanide series, and it is traditionally counted among the rare earth elements; it can also be classified as the first element of the 6th-period transition metals.

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 researchers found lutetium as an impurity in 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 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, although it is 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, used to determine the age of minerals and 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. 177Lu-DOTA-TATE is used for radionuclide therapy on neuroendocrine tumours. Lutetium has the highest Brinell hardness of any lanthanide, at 890–1300 MPa.

Details

Lutetium (Lu) is a chemical element, a rare-earth metal of the lanthanide series of the periodic table, that is the densest and the highest-melting rare-earth element and the last member of the lanthanide series.

In its pure form, lutetium metal is silvery white and stable in air. The metal is easily dissolved in diluted acids—except hydrofluoric acid (HF), in which a protective layer of LuF3 forms on the surface and prevents the metal from further dissolution. The metal is paramagnetic from 0 K (−273 °C, or −460 °F) to its melting point at 1,936 K (1,663 °C, or 3,025 °F) with a temperature-independent magnetic susceptibility between approximately 4 and 300 K (−269 and 27 °C, or −452 and 80 °F). It becomes superconducting at 0.022 K (−273.128 °C, or −459.63 °F) and pressures exceeding 45 kilobars.

Lutetium was discovered in 1907–08 by Austrian chemist Carl Auer von Welsbach and Georges Urbain, working independently. Urbain derived the name for the element from Lutetia, the ancient Roman name for Paris, to honour his native city. The name lutetium became widely accepted except in Germany, where it was commonly called cassiopeium until the 1950s. One of the rarest of the rare earths, lutetium occurs in rare-earth minerals such as laterite clays, xenotime, and euxenite. Though lutetium composes only trace mounts (less than 0.1 percent by weight) of the commercially important minerals bastnasite and monazite, it has proved feasible to extract the metal as a by-product. Lutetium is also found in the products of nuclear fission.

Natural lutetium consists of two isotopes: stable lutetium-175 (97.4 percent) and radioactive lutetium-176 (2.6 percent, 3.76 × {10}^{10}-year half-life). The radioactive isotope is used to determine the age of meteorites relative to that of Earth. In addition to lutetium-176, and not counting nuclear isomers, 33 more radioactive isotopes of lutetium are known. They range in mass from 150 to 184; the least stable isotope (lutetium-150) has a half-life of 45 milliseconds, and the most stable isotope is lutetium-176.

Separation and purification are accomplished by liquid-liquid extraction or ion-exchange techniques. The metal is prepared by metallothermic reduction of the anhydrous halides by alkali or alkaline-earth metals. Lutetium is monomorphic and has a close-packed hexagonal structure with a = 3.5052 Å and c = 5.5494 Å at room temperature.

Lutetium is used in research. Its compounds are used as hosts for scintillators and X-ray phosphors, and the oxide is used in optical lenses. The element behaves as a typical rare earth, forming a series of compounds in oxidation state +3, such as lutetium sesquioxide, sulfate, and chloride.

Element Properties

atomic number  :  71
atomic weight  :  174.967
melting point  :  1,663 °C (3,025 °F)
boiling point  :  3,402 °C (6,156 °F)
specific gravity  :  9.841 (24 °C, or 75 °F)
oxidation state  :  +3.

Additional Information:

Appearance

A silvery-white, hard, dense metal.

Uses

Lutetium is little used outside research. One of its few commercial uses is as a catalyst for cracking hydrocarbons in oil refineries.

Biological role

Lutetium has no known biological role. It has low toxicity.

Natural abundance

In common with many other lanthanides, the main source of lutetium is the mineral monazite. It is extracted, with difficulty, by reducing the anhydrous fluoride with calcium metal.

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