AskDefine | Define lutetium

Dictionary Definition

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

User Contributed Dictionary

see Lutetium


Alternative spellings

  • lutecium (no longer used after 1949, when lutetium was made the official spelling)




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


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chemical element

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  1. lutetium

Extensive Definition

Lutetium () is a chemical element with the symbol Lu and atomic number 71. A silvery-white rare metal, lutetium is the heaviest member of the rare-earth group. Its radioactive isotope is used in nuclear technology to determine the age of meteorites. lutetium usually occurs in association with yttrium and is sometimes used in metal alloys and as a catalyst in various processes. A strict correlation between periodic table blocks and chemical series for neutral atoms would describe lutetium as a transition metal because it is in the d-block, but it is a lanthanide according to IUPAC.

Notable characteristics and applications

Lutetium is a silvery white corrosion-resistant trivalent metal that is relatively stable in air. Lutetium is the heaviest and hardest of the rare earth elements. Lutetium has the highest melting point of any lanthanide, probably related to the lanthanide contraction.
This element is very expensive to obtain in useful quantities and therefore it has very few commercial uses. However, stable lutetium can be used as catalysts in petroleum cracking in refineries and can also be used in alkylation, hydrogenation, and polymerization applications.
Lutetium-176 (176Lu) has been used to date the age of meteorites.
Lutetium aluminium garnet (Al5Lu3O12) has been proposed for use as a lens material in high refractive index immersion lithography.
Lutetium-177 (177Lu), when bound to Octreotate (a somatostatin analogue), is used experimentally in targeted radionuclide therapy for neuroendocrine tumours.
Cerium-doped lutetium oxyorthosilicate (LSO) is currently the preferred compound for detectors in positron emission tomography (PET.)


Lutetium (Latin Lutetia meaning Paris) 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 thought by Swiss chemist Jean Charles Galissard de Marignac (and most others) to consist entirely of the element ytterbium.
The separation of lutetium from Marignac's ytterbium was first described by Urbain and the naming honor therefore went to him. He chose the names neoytterbium (new ytterbium) and lutecium for the new element but neoytterbium was eventually reverted back to ytterbium and in 1949 the spelling of element 71 was changed to lutetium.
Welsbach proposed the names cassiopium for element 71 (after the constellation Cassiopeia) and aldebaranium for the new name of ytterbium but these naming proposals where rejected (although many German scientists in the 1950s called the element 71 cassiopium).


Found with almost all other rare-earth metals but never by itself, lutetium is very difficult to separate from other elements. Consequently, it is also one of the most expensive metals, costing about six times as much as gold.
The principal commercially viable ore of lutetium is the rare earth phosphate mineral monazite: (Ce, La, etc.) PO4 which contains 0.003% of the element. Pure lutetium metal has only relatively recently been isolated and is very difficult to prepare (thus it is one of the most rare and expensive of the rare earth metals). It is separated from other rare earth elements by ion exchange and then obtained in the elemental form by reduction of anhydrous LuCl3 or LuF3 by either an alkali metal or alkaline earth metal.


Naturally occurring lutetium is composed of 1 stable isotope 175Lu (97.41% natural abundance) and 1 long-lived beta-radioactive isotope 176Lu with a half-life of 3.78×1010 years (2.59% natural abundance). The last one is used in the radiometric dating (see Lutetium-hafnium dating). 33 radioisotopes have been characterized, with the most stable being naturally occurring 176Lu, and artificial isotopes 174Lu with a half-life of 3.31 years, and 173Lu with a half-life of 1.37 years. All of the remaining radioactive isotopes have half-lives that are less than 9 days, and the majority of these have half-lives that are less than a half an hour. This element also has 18 meta states, with the most stable being 177mLu (T½=160.4 days), 174mLu (T½=142 days) and 178mLu (T½=23.1 minutes).
The known isotopes of lutetium range in atomic weight from 149.973 (150Lu) to 183.961 (184Lu). The primary decay mode before the most abundant stable isotope, 175Lu, is electron capture (with some alpha and positron emission), and the primary mode after is beta emission. The primary decay products before 175Lu are element 70 (ytterbium) isotopes and the primary products after are element 72 (hafnium) isotopes.


Lutetium is very expensive (upwards of $100 per gram) to obtain on useful quantities and therefore it has very few commercial uses. Some commercial applications include:
Intermetalic compounds:


Like other rare-earth metals lutetium is regarded as having a low degree of toxicity but it and especially its compounds should be handled with care nonetheless. Metal dust of this element is a fire and explosion hazard. Lutetium plays no biological role in the human body but is thought to help stimulate metabolism.


lutetium in Afrikaans: Lutetium
lutetium in Arabic: لوتيتيوم
lutetium in Bengali: লুটেটিয়াম
lutetium in Belarusian: Лютэцый
lutetium in Bosnian: Lutecijum
lutetium in Catalan: Luteci
lutetium in Czech: Lutecium
lutetium in Corsican: Luteziu
lutetium in Danish: Lutetium
lutetium in German: Lutetium
lutetium in Estonian: Luteetsium
lutetium in Modern Greek (1453-): Λουτήτιο
lutetium in Spanish: Lutecio
lutetium in Esperanto: Lutecio
lutetium in Basque: Lutezio
lutetium in French: Lutécium
lutetium in Friulian: Lutezi
lutetium in Manx: Lootaiçhum
lutetium in Galician: Lutecio
lutetium in Korean: 루테튬
lutetium in Armenian: Լուտեցիում
lutetium in Croatian: Lutecij
lutetium in Ido: Lutecio
lutetium in Indonesian: Lutesium
lutetium in Icelandic: Lútetín
lutetium in Italian: Lutezio
lutetium in Hebrew: לוטציום
lutetium in Javanese: Lutetium
lutetium in Kannada: ಲ್ಯುಟೇಶಿಯಮ್
lutetium in Haitian: Litesyòm
lutetium in Kurdish: Lûtesyûm
lutetium in Latin: Lutetium
lutetium in Latvian: Lutēcijs
lutetium in Luxembourgish: Lutetium
lutetium in Lithuanian: Lutecis
lutetium in Lojban: jinmrluteti
lutetium in Hungarian: Lutécium
lutetium in Malayalam: ലുറ്റീഷ്യം
lutetium in Dutch: Lutetium
lutetium in Japanese: ルテチウム
lutetium in Norwegian: Lutetium
lutetium in Norwegian Nynorsk: Lutetium
lutetium in Polish: Lutet
lutetium in Portuguese: Lutécio
lutetium in Russian: Лютеций
lutetium in Sicilian: Lutezziu
lutetium in Simple English: Lutetium
lutetium in Slovak: Lutécium
lutetium in Slovenian: Lutecij
lutetium in Serbian: Лутецијум
lutetium in Serbo-Croatian: Lutecijum
lutetium in Finnish: Lutetium
lutetium in Swedish: Lutetium
lutetium in Thai: ลูทีเทียม
lutetium in Turkish: Lutesyum
lutetium in Ukrainian: Лютецій
lutetium in Chinese: 镥
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