Lithium

Lithium (Greek: λιθίον 'pebble') is a chemical element symbol Li and atomic number 3. On the periodic table, it is found in group 1, among the alkaline elements. In its pure form, it is a soft, silvery-white metal that oxidizes rapidly in air or water. Its density is half that of water, being the lightest, softest and whitest metal and solid element.

3D representation of Lithium atom formed by a nucleus of red protons and blue neutrons surrounded by electrons.

Like the other alkali metals, it is univalent and highly reactive, although less so than sodium, so it is not found free in nature. Approached to a flame it turns crimson but, if the combustion is violent, the flame acquires a brilliant white color.

It is used especially in heat-conducting alloys and in electric batteries. Regarding its salts, they are often used in the treatment of bipolar disorder.

Etymology

Lithium takes its name from the Greek λίθoς -ου, 'stone'. The element's name comes from the fact that it was discovered in a mineral, while the rest of the alkali metals were discovered in plant tissue.

History

Lithium was discovered by Johann Arfvedson in 1817. Arfvedson found this element in spodumene and lepidolite from a petalite mine, LiAl (Si₂O₅) ₂, from the island Utö (Sweden) that I was analyzing. In 1818 Christian Gmelin was the first to observe that lithium salts turn flames bright red. Both tried unsuccessfully to isolate the element from its salts, which William Thomas Brande and sir Humphrey Davy eventually succeeded in doing by electrolysis of lithium oxide.

In 1923 the German company Metallgesellschaft AG began producing lithium by electrolysis of molten lithium chloride and potassium chloride.

The “lithium triangle” made up of the Salar de Uyuni in Bolivia, the Salar de Atacama in Chile and the Salar del Hombre Muerto in Argentina, concentrates approximately between 50 and 85% of this mineral. The growth The accelerated use of lithium-ion has caused a ton of lithium to rise in price, from the $450 it cost in 2003 to $65,000 in 2022.

In Spain, mining of lithium stopped in 2011. In Cáceres, 15,000 tons per year could be produced, but the city's socialist government was opposed in 2021.

Use

Due to its high specific heat, lithium is used in heat transfer applications, and due to its high electrochemical potential it constitutes a suitable anode for electric batteries. It is also given the following uses:

• Lithium chloride and lithium bromide have a high higroscopicity so they are excellent dryers. The second is used in contraction heat pumps, among other compounds such as lithium nitrate.
• Lithium salts, particularly lithium carbonate (Lil₂CO₃) and lithium citrate, are used in the treatment of mania, depression and bipolarity, as well as in other psychopathologies. It's a mood stabilizer. Its mechanisms of action are several: 1. Blocks the release of dopamine -blocks the hypersensitivity of dopaminergic receptors-; 2. Blocks results in the post-inaptic neuron - unlocks the reuse of phosphate groups of the inositol triphosphate that activates the release of calcium-; 3. Replace the sodium in the synaptic channel by being smaller and the action potential slows down, making the patient calm down. Lithium is not substrate for the sodium potassium ATPasa pump that prevents the passage of sodium ions, replacing the concentration of sodium, which in high concentrations can be toxic.
• Lithium stearate is a general purpose lubricant in high temperature applications.
• Lithium is a highly employed agent in the synthesis of organic compounds, used for the coordination of ligands through the litiate intermediate.
• Lithium hydroxide is used in spacecraft and submarines to clean air by extracting carbon dioxide.
• It is a common component of aluminum, cadmium, copper and manganese alloys used in aeronautic construction, and has been successfully used in the manufacture of ceramics and lenses, such as the 5,08 m diameter telescope (200 inches) of Monte Palomar.
• It also has nuclear applications.

Abundance and obtaining

Lithium is a moderately abundant element and is present in the Earth's crust at 65 parts per million (ppm). This places it below nickel, copper, and tungsten and above cerium and tin, in terms of its abundance on the planet.

Argentina, Bolivia, Chile and Peru have 85% of the planet's lithium reserves; It is found dispersed in a small proportion in certain volcanic rocks and natural salts, but never free, given its great reactivity in the Salar de Uyuni in Bolivia or the Salar del Hombre Muerto in Argentina Salar de Atacama in Chile (5% of the reserves). There are other smaller salt flats in Manaure (Colombia) and other important deposits recently located in Afghanistan. Since 2010, research has been carried out in Afghanistan on reserves whose magnitude has yet to be precisely determined, but which could radically change the evaluation of the aforementioned percentages and the evolution of political and economic events in that country.

Trace traces of lithium and beryllium, along with hydrogen and helium, represent the only elements obtained after the Big Bang. All the others were synthesized through nuclear fusions in main sequence stars or during supernovae outbursts. Industrially it is obtained by electrolysis of molten lithium chloride (LiCl).

Since World War II lithium production has increased enormously, separating it from the rocks of which it is a part and from mineral waters. The main minerals from which it is extracted are lepidolite, petalite, spodumene and amblygonite. In the United States it is obtained from the salt flats of California and Nevada mainly.

A different picture emerges when analyzing the companies that manage lithium mines. According to a report by the specialized magazine illuminem, Chinese investors control several mining companies, which account for 33.1% of the total production (and half of the production of large companies) of lithium in the world.

World production in 2019, in tons per year

1.	Australia	45 000
2.	ChileChile	19 300
3.	ChinaChina	10 800
4.	Argentina	6300
5.	BrazilBrazil	2400
6.	ZimbabweZimbabwe	1200
7.	Portugal	900
8.	CanadaCanada	200

Source: USGS.

Isotopes

There are two stable isotopes of lithium, ⁶Li and ⁷Li, the latter being the most abundant (92.5%). Six radioisotopes have been characterized, the most stable being ⁸Li with a half-life of 838 milliseconds and ⁹Li with one of 178.3 ms. All other radioactive isotopes have half-lives less than 8.5 ms. The unstable isotope ¹¹Li also occurs in the laboratory.

The atomic weights of lithium vary between 4.027 and 11.0348 amu of ⁴Li and ¹¹Li respectively. The main decay mode of isotopes lighter than the most abundant stable isotope (⁷Li) is proton emission (with one case of alpha decay) yielding helium isotopes; while in the heavier isotopes the most common mode is beta decay, (with some cases of neutron emission) resulting in isotopes of beryllium.

⁷Li is one of the primordial elements, produced by nuclear synthesis after the big bang. Lithium isotopes are substantially fractionated in a wide variety of natural processes, including chemical precipitation in mineral formation, metabolic processes, and the replacement of magnesium and iron in crystal lattices of clay minerals where ⁶ Li is preferred over ⁷Li, etc.

Precautions

Like other alkali metals, pure lithium is highly flammable and slightly explosive when exposed to air and especially water. It is also corrosive, so it requires the use of adequate handling methods to avoid contact with the skin. It should be stored in a hydrocarbon liquid such as petroleum jelly or mineral oil. It can cause hypothyroidism by preventing the entry of iodine into the thyroid hormone. Lithium is not a substrate for the sodium potassium ATPase substrate pump that prevents the passage of sodium ions, replacing the sodium concentration, which in high concentrations can be toxic.

On the other hand, to avoid lithium poisoning, an intake of 2.5 – 3.5L of water/day is recommended (water prevents lithium from displacing cations from important places). Avoid caffeine (it is a diuretic that promotes water loss). Eat with salt (so it is achieved that the Na + is displaced with more difficulty by the Li). Be careful with fluid loss (sweat, vomiting, diarrhea, diuretics...).

Biological paper

It is known that it can replace sodium at the level of biological membranes, but it has been found to increase cell permeability and act on neurotransmitters, favoring mood stability. Therefore, it is used as Lithium (medication) to treat and prevent manic episodes in bipolar disorder.