Lithium is an alkali metal that was discovered in 1817. It is a highly reactive metal and is used in variety of applications including, rechargeable batteries and rocket fuel due to its light weight and very high boiling point.
History and Discovery
The element lithium derives its name from the Greek word “lithos” that means stone. It was recovered from its ore, petalite (LiAlSi4O10) by Johan August Arfwedson (1817). The alkaline material was given the name lithium (from lithos) as it was discovered from rock as compared to other metals such as potassium and sodium that were discovered from plants and animal, respectively [1]. Lithium was isolated in pure form by William Thomas Brande (1821), through the process of electrolysis of lithium oxide and later the commercial production of lithium was carried out in 1923. In World War II, lithium was majorly used as greases for the engines of aircrafts. US was the primary producer of lithium between 1960s to mid-1980s. During the Cold War, the production of lithium was increased drastically as it was used in the production of nuclear fusion weapons. And then in late 1990s, as the nuclear arms race met an end, the production and demand of lithium was greatly decreased.
Lithium
| Periodic Table Classification | Group 1 Period 2 |
|---|---|
| State at 20C | Solid |
| Color | Silvery-white |
| Electron Configuration | [He] 2s1 |
| Electron Number | 3 |
| Proton Number | 3 |
| Electron Shell | 2, 1 |
| Density | 0.53 g.cm-3 at 20°C |
| Atomic number | 3 |
| Atomic Mass | 6.94 g.mol -1 |
| Electronegativity according to Pauling | 0.98 |
Occurrence
Lithium have a considerably high reactivity, and it does not allow lithium to exist in free form in nature. It is usually present in ionic compounds, such as pegmatitic minerals. Lithium occurs in ocean water and is commonly obtained from brines. Lithium is also present in biological systems but in trace amounts [1]. Lithium is also considered as one of the first elements that were formed as a result of the Big Bang and have been found to be prevalent in young stars while absent from older stars. As reported by the US Geological Survey, the top three countries of the world with the highest production of lithium include Australia, Chile and Argentina [2]. Lithium is also found in human body, including various organs and fetal tissues.
Physical Characteristics
Lithium is silvery-white in color. It is a relatively soft metal and can be cut with knife. Lithium has an atomic number of 3 and atomic weight of 6.938. Lithium is the lightest metal and the lightest solid at standard conditions. Lithium is a good conductor of heat and electricity [1]. Lithium has quite low melting point among other metals (180 °C) but has the highest boiling and melting point in all alkali metals [3]. Lithium has density of 0.534 g/cm3 which is quite low. It can float on water as well as on lightest hydrocarbon oils. When exposed to extremely low temperatures, lithium becomes superconductive (at standard pressure). Lithium has the highest specific heat capacity (3.58 kilojoules) along all solids [4].
Chemical Characteristics
Lithium is a reactive metal. It is an alkali metal and is highly flammable. When exposed to moist air, it led to rapid corrosion, and turns gray and then into black color. To avoid corrosion, lithium is stored in mineral oil. Lithium burns with a striking crimson color over flame, and when it is exposed to extreme heat it burns with a brilliant sliver flame. Lithium is flammable and can cause potential explosion when exposed to air and water [5].
Significance and Uses
- The largest use of lithium is in the production of high-quality glass and ceramic.
- Lithium is widely used in the production of lithium-ion batteries, that are rechargeable and have a high energy density.
- Lithium is used as lubricant greases worldwide.
- Lithium is widely used in various metallurgy processes.
- Lithium chloride is highly hygroscopic (ability to absorb moisture from air) and are used as desiccants for gas streams.
- Lithium aluminum hydride can also be used by as a solid fuel and metallic lithium as rocket propellants [7].
- Lithium-6 (isotope of lithium) is used in the production of tritium and as a neutron absorber in nuclear fusion reactions.
- Lithium salts are used to treat various mental disorders, including bipolar disorder, depression and schizoaffective disorder [8].
Health Hazards
Lithium is a reactive and corrosive element. Its contact with skin can lead to burns and blisters. Inhalation of lithium dust can lead to irritability of nose and throat. Long term exposure to lithium lead to damage of lungs (pulmonary edema). Lithium is stored in naphtha, a non-reactive compound, to increase its shelf-life.
Isotopes of Lithium
There are around 11 known isotopes of lithium, but only two are stable. Lithium 6 and lithium 7 are the stable isotopes with a natural abundance of 7.9 and 92.41 %. The rest of the lithium isotopes are unstable and have an extremely little half-life.
REFERENCES
[1]. Krebs, Robert E. (2006). The History and Use of Our Earth’s Chemical Elements: A Reference Guide. Westport, Conn.: Greenwood Press. ISBN 0-313-33438-2.
[2] “8 Top Lithium-producing Countries”. Commodity.com. December 14, 2017. Retrieved 2017-12-14.
[3] Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
[4] Hammond, C. R. (2000). The Elements, in Handbook of Chemistry and Physics (81st ed.). CRC press. ISBN 0-8493-0481-4.
[5]. XXIV.—On chemical analysis by spectrum-observations”. Quarterly Journal of the Chemical Society of London. 13 (3): 270. 1861. doi:10.1039/QJ8611300270.
[6] Boesgaard, A. M.; Steigman, G. (1985). “Big bang nucleosynthesis – Theories and observations”. Annual Review of Astronomy and Astrophysics. Palo Alto, CA. 23: 319–378. Bibcode:1985ARA&A..23..319B. doi:10.1146/annurev.aa.23.090185.001535. A86-14507 04–90.
[7]. Emsley, John (2001). Nature’s Building Blocks. Oxford: Oxford University Press. ISBN 0-19-850341-5.
[8]. Kean, Sam (2011). The Disappearing Spoon.