Li - Lithium

Properties

Lithium is a very soft, light metal and is silver in colour; it is the 31st most abundant element within the Earth’s crust. It belongs to the group of Alkali Metals, meaning that it is highly reactive, due to it having one electron in its outermost shell. As Lithium is so reactive, it must be stored in an oxygen-free environment, so that it is not oxidised. Usually it is stored in Vaseline (petroleum jelly). This high level of reactivity means that it is rarely found in nature and, therefore, must be obtained from ores. Lithium is the least dense of all the solid elements (under normal conditions) and along with Sodium (Na) is the only metal that floats on water.

Another interesting property of Lithium is that it has the highest specific heat capacity of any solid element (3.489 J/g mol at 20°C), meaning that it is an efficient heat transfer medium. This is due to the great difference in temperature between melting and boiling points, 180.54°C and 1342°C respectively. Lithium is highly flammable and when burnt releases toxic fumes causing a burning sensation and coughing in humans. Ingestion of the element is also toxic and, depending on the dosage, can have different effects, varying from slurred speech and confusion to death.

History

Lithium is a very rare element within the Universe, despite the fact that it was one of the three initial elements, along with hydrogen and helium, to be created. However, young stars contain many times the amount of lithium than was present at the beginning of the Universe, meaning that there are natural processes that have the ability to create lithium. Lithium was discovered in 1817 in Stockholm, Sweden, by Johan August Arfvedson, during an analysis of petalite (LiAlSi4O10), which is a lithium-containing mineral. Whilst observing this mineral, Arfvedson noticed that a previously undiscovered metal was present, but was unable to separate it using electrolysis. William T. Brande first isolated a tiny amount in 1821, although it was not until 1855 when Robert Bunsen and Augustus Matthiessen (independently) isolated the element by electrolysis of molten lithium chloride.

Sources

Lithium is sourced from igneous rocks, clays and natural brines. The main producers of lithium are the USA, Russia, China, Australia, Zimbabwe and Brazil, although the majority is manufactured in Chile from natural brines.  Global production of lithium (both lithium ores and brine salts) is around 40,000 tonnes per year, with reserves of around 7 million tonnes, half of which are in salt lakes.

Uses

Lithium has many and varied applications. The main industrial use for lithium is in the stearatum form as the thickener in lubricant grease.  It is also used to extend battery performance, with lithium-ion batteries used to power electronic devices as varied as pacemakers and laptops. Its alloys are used to make high performace aircraft components.

Lithium carbonate is used in medicine as an anti-depressant for bi-polar disorder, as it regulates the the extreme mood swings associated with this mental illness.

Lithium chloride and bromine form brine when mixed, which is particularly effective at absorbing humidity, making it useful in air conditioning units.

It is also used as an additive in pottery.