Lutetium

Notable characteristics and applications

Lutetium is a silvery white 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 polymerization applications.

Lutetium-176 (¹⁷⁶Lu) has been used to date the age of meteorites.

Lutetium aluminum garnet (Al₅Lu₃O₁₂) has been proposed for use as a lens material in high immersion lithography.

Cerium-doped lutetium oxyorthosilicate (LSO) is currently the preferred compound for detectors in positron emission tomography (PET.) ^[2]

History

Lutetium (Latin Lutetia meaning Paris) was independently 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).

Occurrence

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 alkaline earth metal.

Isotopes

Main article: isotopes of lutetium

Naturally occurring lutetium is composed of 1 stable 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 Lu-177m (t_½ 160.4 days), Lu-174m (t_½ 142 days) and Lu-178m (t_½ 23.1 minutes).

The isotopes of lutetium range in hafnium) isotopes.

Applications

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:

• Use as a pure beta emitter, using lutetium which has been exposed to neutron activation. A tiny amount of lutetium is added as a dopant to gadolinium gallium garnet (GGG), which is used in magnetic bubble memory devices.
• Use as a catalyst in the petroleum industry, or in organic light-emitting diodes (OLEDs).
• Research into possible uses for targeted radiotherapy for the development of new cancer therapies.

Compounds

Nitride: LuN

Intermetalic compounds:

• Lutetium aluminum garnet

See also lutetium compounds.

Precautions

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.

References

• Guide to the Elements - Revised Edition, Albert Stwertka, (Oxford University Press; 1998) ISBN 0-19-508083-1
• Los Alamos National Laboratory's Chemistry Division: Periodic Table - Lutetium

1. ^ IUPAC Provisional Recommendations for the Nomenclature of Inorganic Chemistry (2004) (online draft of an updated version of the "Red Book" IR 3-6)
2. ^ Thompson CJ. Instrumentation. In: Wahl RL,ed. Principles and Practice of Positron Emission Tomography. Philadelphia: Lippincott Williams and Wilkins, 2002:51.
3. ^ http://acswebcontent.acs.org/landmarks/landmarks/rareearth/discovery.html