Lutetium was discovered in 1907. It is a rare and expensive element and is the last member of lanthanide series. It is used as a catalyst in organic chemical industry.
History and Discovery
Lutetium was discovered independently by Georges Urbain (French chemist) and Carl Auer von Welsbach (Australian scientist) and Charles James (American chemist) in 1907. They all found it as an impurity in ytterbium. In 1907, Georges Urbain separated ytterbia into two components neoytterbia and lutecia. Neoytterbia later called ytterbium and lutecia was known as lutetium. In the same time, Carl Auer von Welsbach independently carried out research, but he called new element aldebaranium and cassiopeium. Its names were finalized as lutetium by Geroge Urbain in 1907. Its pure metal form was manufactured in 1953 [1]. The symbol of lutetium is Lu.
Lutetium
| Periodic Table Classification | Group n/a Period 6 |
|---|---|
| State at 20C | Solid |
| Color | Silvery white |
| Atomic number | 71 |
| Electron Configuration | [Xe] 4f14 5d1 6s2 |
| Electron Number | 71 |
| Proton Number | 71 |
| Electron Shell | 2, 8, 18, 32, 9, 2 |
| Density | 9.84 g.cm-3 at 20°C |
| Atomic Mass | 174.97 g.mol -1 |
| Electronegativity according to Pauling | 1.27 |
Occurrence
Lutetium is not an abundant element. It is not found free in nature and is present along with several rare minerals. It is commonly found as constituent of yttrium minerals. [2]. Lutetium is quite rare and its extraction is also very challenging. It is considered as the most expensive rare earth metals and is has a price around one-fourth of gold [2]. The main deposits of lutetium are found in China, Brazil, USA, India, Sri Lanka and Australia [1].
Physical Characteristics
Lutetium is a whitish silver metal and is the hardest metal in the lanthanide series. It is unstable in air and can burn at 150C to form lutetium oxide Lutetium has the highest melting point among the lanthanides, 1652 °C and boiling point is 3402 °C. The density of lutetium is also the highest among the other members of lanthanide series and is around 9.841 g/cm3 at room temperature [3].
Chemical Characteristics
Lutetium is tarnished in moist air. It is rapidly dissolved in weak acids. Lutetium reacts with water and forms lutetium hydroxide. It also reacts with four halogens, except fluoride to form trihalides. Most salts of lutetium are soluble in water and produce white crystals when the solution is dried. Lutetium sulfate, lutetium nitrate and lutetium acetate are water soluble while lutetium carbonate, lutetium oxide are insoluble. Lutetium mostly exist in +3 and oxidation states.
Significance and Uses
- Lutetium is rare and expensive, so it has few commercial uses. For instance, it is used as catalyst in petroleum industry.
- Lutetium is used to carry out polymerization, alkylation and hydrogenation reactions.
- Lutetium is used to make various useful alloys. For instance, lutetium aluminum garnet is used to make lens.
- Lutetium aluminum is used to make phosphor in LED light bulbs.
- Lutetium-176 is used to in dating of rocks and meteorites.
- Lutetium tantalite is used as ideal host for X-ray phosphor as it has tremendously high density and is very stable.
- Lutetium-177 is a medically useful isotope and is used for treatment of bone palliation and tumor therapy, especially endocrine tumors.
Health Effects
Lutetium in pure form is non-toxic. It can sometime cause skin and eye irritation. However, its salts, especially water-soluble compounds, are toxic. Lutetium compounds should be stored in closed container and must be protected from moisture and direct contact with air.
Isotopes of Lutetium
Lutetium has two isotopes: lutetium-175 and lutetium-176. The isotope lutetium-176 has an abundance of 2.5% and is a radioactive isotope. It has a half-life of 38 billion years [?]. There are around 32 synthetic radioactive isotopes of lutetium (lutetium-150 to lutetium-184), their atomic masses ranging from 149.97 to 183.96. The most stable radioactive isotope is lutetium-174 and has a half-life of 1.37 years.
REFERENCES
[1]. Emsley, John (2001). Nature’s building blocks: an A-Z guide to the elements. Oxford University Press. pp. 240–242. ISBN 978-0-19-850341-5.
[2]. Hedrick, James B. “Rare-Earth Metals” (PDF). USGS. Retrieved 2009-06-06.
[3]. Parker, Sybil P. (1984). Dictionary of Scientific and Technical Terms (3rd ed.). New York: McGraw-Hill.
[4]. Georges, Audi; Bersillon, O.; Blachot, J.; Wapstra, A. H. (2003). “The NUBASE Evaluation of Nuclear and Decay Properties” (PDF). Nuclear Physics A. 729 (1): 3–128. Bibcode:2003NuPhA.729….3A. CiteSeerX 10.1.1.692.8504. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2016-01-17.