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Lutetium [Lu]
CAS-ID: 7439-94-3
An: 71 N: 104
Am: 174.967 (1) g/mol
Group No: 3
Group Name: Lanthanoids
Block: d-block  Period: 6
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 3675K (3402°C)
Melting Point: 1925K (1652°C)
Superconducting temperature: 0.022K (-273.128°C)
Density: 9.841g/cm3
Discovery Information
Who: Georges Urbain
When: 1907
Where: France
Name Origin
From Lutetia the ancient name of Paris.
 "Lutetium" in different languages.
Sources
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).
Primary mining locations are the USA, Brazil, India, Sri Lanka, Australia and China. Annual production is around 10 tons.
Abundance
 Universe: 0.0001 ppm (by weight)
 Sun: 0.001 ppm (by weight)
 Carbonaceous meteorite: 0.03 ppm
 Earth's Crust: 0.51 ppm
 Seawater:
   Atlantic surface: 1.4 x 10-7 ppm
   Atlantic deep: 2 x 10-7 ppm
   Pacific surface: 6 x 10-8 ppm
   Pacific deep: 4.1 x 10-7 ppm
Uses
This element is very expensive to obtain in useful quantities and therefore it has very few commercial uses. Used in alloys and can be used as a catalyst in cracking, hydrogenation, polymerization and alkylation.
A tiny amount of lutetium is added as a dopant to gadolinium gallium garnet (GGG), which is used in magnetic bubble memory devices.
History
Lutetium (Latin Lutetia meaning Paris) was independently discovered in 1907 by French scientist Georges Urbain and Austrian mineralogist Baron Carl Auer von Welsbach. Both 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 albebaranium for the new name of ytterbium but these naming proposals where rejected (although many German scientists in the 1950s called the element 71 cassiopium).
Notes
Because of the difficulty in producing pure lutetium it is one of the most expensive metals, costing around six times as much per gram as gold.
Hazards
Like other rare-earth metals lutetium is regarded as having a low toxicity rating 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.
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