Lithium price, history, occurrence, extraction and use

Lithium (derived from ancient Greek λίθος líthos 'stone', pronunciation [liːti̯ʊm] or also [liːʦi̯ʊm]) is a chemical element with the symbol Li and the atomic number 3. It is an element of the 1. IUPAC group, the group of alkali metals, and belongs to the second period of the Periodic Table of the Elements. Lithium is a light metal and has the lowest density of solid elements under standard conditions.

Lithium is not found to be elemental in nature due to its high reactivity. At room temperature, it is only stable in completely dry air for a long time, but slowly reacts to lithium nitride. In moist air, a dull gray lithium hydroxide layer quickly forms on the surface. Like all alkali metals, elemental lithium already reacts with the skin's moisture, causing severe burns and burns. Many lithium compounds which form lithium ions in aqueous solution are characterized as harmful to health, in contrast to the corresponding sodium and potassium compounds.

As a trace element, lithium is a common constituent of mineral water in the form of its salts. There are small amounts of lithium in the human body; however, the element is not essential and has no known biological function. However, some lithium salts have medicinal properties and are used in lithium therapy for bipolar affect disorders, mania, depression, and cluster headaches (see Medicine).

 

History

The discoverer of lithium is the Swede Johan August Arfwedson, who discovered in 1817 the presence of a foreign element in Petalit and soon afterwards also in spodumene and lepidolite, when he analyzed mineral finds from the island of Utö in Sweden. His academic teacher Jöns Jakob Berzelius suggested Lithion, a derivation of Greek λίθος líthos 'stone', as a name, which, according to the names of the other two known alkali metals sodium and potassium, indicates the material from which it was obtained Finally, lithium has prevailed in its latinized form.

1818 was the German chemist Christian Gottlob Gmelin, who noted that lithium salts give a red flame coloration. Both scientists failed in the following years with attempts to isolate this element. This was first achieved by William Thomas Brande and Sir Humphry Davy in the year 1818 by means of an electrolytic process of lithium oxide (Li2O). Robert Bunsen and Augustus Matthiessen produced 1855 by electrolysis of lithium chloride (LiCl) larger amounts of pure lithium. In the year 1917, Wilhelm Schlenk synthesized the first organolithium compounds from organic mercury compounds.

With the first commercial production 1923 started the German metal company in the Hans-Heinrich-Hütte in Langelsheim in the Harz, where a melt of lithium and potassium chloride (KCl) was electrolyzed.

Until shortly after the Second World War there were hardly any applications for lithium apart from the application as lubricant (mineral oil, thickened with lithium stearate) and in the glass industry (lithium carbonate or lithium oxide). This changed when tritium, which can be obtained from lithium, was needed in the United States for the construction of hydrogen bombs. It started with a broad promotion, especially in Kings Mountain, North Carolina. Due to the short lithium tritium half-life required large amounts of lithium was accumulated between 1953 and 1963 a large supply of lithium, which was brought only after the end of the Cold War from 1993 on the market. In addition to mining, the cheaper extraction from brines was now important. Larger amounts of lithium are now used for batteries, for the polymerization of elastomers, in the construction industry and for the organic synthesis of pharmaceuticals and agrochemicals. Since 2007 primary batteries and accumulators (secondary batteries) are the most important segment.

 

Occurrence and degradation

Lithium accounts for about 0,006% of the Earth's crust. It is thus less common than zinc, copper and tungsten and slightly more common than cobalt, tin and lead in the earth's crust. Although lithium is more abundant than lead, for example, it is difficult to obtain by distributing it more. The drinking water and some foods such as meat, fish, eggs and dairy products contain lithium. For example, 100 g meat contains about 100 μg of lithium. Various plants, such as tobacco or buttercup, pick up lithium compounds from the soil and accumulate them. The average dry matter content of plants is between 0,5 ppm and 3 ppm. In the waters of the oceans the mean concentration is 180 ppb and in river water only about 3 ppb.

 

Mining and reserves

In terms of volume, 2015 was sourced 35.000 tonnes of lithium outside the United States and traded primarily as lithium carbonate (Li2CO3); the reserves in the existing mines are estimated at around 16 million tons (as of March 2018). The global deposit of continental brine, geothermal brine, hectorite mineral, oilfield brine and magma rock pegmatite is estimated at 53,8 million tons.

Lithium occurs in some minerals in lithium pegmatites. The most important minerals are amblygonite, lepidolite, petalite and spodumene. These minerals have a lithium content of up to 9% (amblygonite). Other, less common lithium ores are cryolite ion (Li3Na3 [AlF6] 2), which has the largest lithium content of all minerals, triphylin and tin forestite. Lithium minerals are present in many silicate rocks, but usually only in low concentrations. There are no large deposits. Since the extraction of lithium from these minerals is associated with great expense, they now play a minor role in the production of lithium or lithium compounds, but this could change due to the expected high demand. Mining sites are primarily the Greenbushes and Mt. Cattlin mines in Western Australia, where there is high lithium concentration in their pegmatite rocks and where lithium is a by-product of tantalum recovery. Also in some other countries, such as Canada and Russia, until 1998 also in Bassemer City, North Carolina, spodumene is mined for lithium production.

Europe has Li-rich pegmatite fields on the Carinthian Weinebene in the district of Wolfsberg, in the Finnish region of Österbotten, in the Ore Mountains and between Spain (Almendra) and Portugal (Guarda district, Boticas).

The deposits in Austria and Finland are being developed by Global Strategic Metals and Keliber, respectively, and could be operational from 2021. The occurrence at Zinnwald in the Erzgebirge is being explored by SolarWorld.

 

Secondary deposits

Lithium salts, in particular lithium chloride, are also common in brines, mostly salt lakes. The concentration can be up to one percent. In addition to the concentration of lithium, the ratio of magnesium to lithium is important for the quality of the brine. Currently, lithium is mainly used in Chile (Salar de Atacama, which has 0,16% with the highest known lithium content), Argentina (Salar de Hombre Muerto), the United States of America (Silver Peak, Nevada) and the People's Republic of China (Chabyêr Caka , Tibet, Taijinaier Lake, Qinghai). Salar de Uyuni, the Bolivian salt lake with an estimated 5,4 million tons of lithium, may be the source of the largest resources. The state-owned Yacimientos de Litio Bolivianos has been investing heavily in its industrialization, including neighboring Salar de Coipasa and Laguna Pastos Grandes, with Chinese and German partners since 2018. There are other lithium-bearing salt lakes that are not yet being used for industrial mining at April 2019, such as China, Argentina and Afghanistan. 2016 became known in Utah (USA) sols as 1700 mg / L Li, where oil exploration drilling was already carried out in the 1960s.

Potassium carbonate (potash), borax, cesium and rubidium are frequently obtained as co-products in lithium production.

Due to the expected strong demand for lithium for electric vehicle batteries, some companies are currently exploring the mining of lithium minerals and brine in various regions of the world, including Europe. Also researched is the lithium production from seawater. In the oceans about 230 billion tons of lithium are dissolved. 2018 researchers presented an extraction method in which lithium can be obtained from seawater via solar-powered electrolysis. As an advantage over conventional recovery, they mentioned that the process directly produces metallic lithium and therefore can dispense with the (complex and energy-intensive) processing required by traditional lithium ore mining.

 

Occurrence outside the earth

After the big bang, besides hydrogen and helium isotopes, a considerable amount of the isotope 7Li was also formed. However, for the most part, this is no longer present today because stars in lithium have been fused with hydrogen in the process of the proton-proton reaction II and thus consumed. In brown dwarfs, however, mass and temperature are not high enough for hydrogen fusion; their mass does not reach the necessary size of about 75 Jupiter masses. The lithium produced during the Big Bang thus remained in larger quantities only in brown dwarfs. For this reason, lithium is also a relatively rare element in extraterrestrial form, but it can be used to detect brown dwarfs.

The distribution of lithium in different stars varies widely, although age, mass, and metallicity are similar. It is believed that planets have an influence on the lithium content of a star. If a star has no planets, the lithium content is high, while stars like the sun, which are surrounded by planets, have a low lithium content, which is also known as lithium dip. The cause is thought to be that the tidal forces of planets contribute to a greater intermingling of outer and inner layers in stars, so that more lithium gets into an area that is hot enough to fuse it.

 

production process

Lithium is obtained mainly from salt water (groundwater, salt lakes) by evaporation. Rare is the extraction of rocks in open pit mining.

From salt water

For lithium extraction, saline groundwater is pumped to the surface and passed through a chain of evaporation ponds, where evaporation takes place in the sun for several months. Once the lithium chloride in the ponds reaches the required concentration, the solution is pumped to a treatment plant where unwanted boron or magnesium is extracted and filtered out. Then she is treated with sodium carbonate. The precipitated lithium carbonate is filtered and dried. Excess residual brine is pumped back to the salt lake. In arid areas such as Chile, the use of groundwater promotes the drying up of the landscape.

presentation

From lithium-containing salt solutions is precipitated by evaporation of water and addition of sodium carbonate (soda) lithium carbonate. For this purpose, the brine is first concentrated in air until the lithium content exceeds 0,5%. The sparingly soluble lithium carbonate precipitates from this by addition of sodium carbonate:

To obtain metallic lithium, the lithium carbonate is first reacted with hydrochloric acid. This produces carbon dioxide, which escapes as gas, and dissolved lithium chloride. This solution is concentrated in a vacuum evaporator until the chloride crystallizes out:

The apparatus and equipment for lithium chloride extraction must be made of special steels or nickel alloy, as the brine has a very corrosive effect. Metallic lithium is produced by fused-salt electrolysis of a 450-500 ° C melting eutectic mixture of 52 mass% lithium chloride and 48 mass% potassium chloride:

The potassium is not deposited in the electrolysis, because it has a lower electrode potential in the chloride melt. Traces of sodium, however, are deposited and make the lithium particularly reactive (beneficial in organic chemistry, bad for Li batteries). The liquid lithium accumulates on the electrolyte surface and can be relatively easily discharged from the electrolysis cell. It is also possible to recover lithium by electrolysis of lithium chloride in pyridine. This method is particularly suitable on a laboratory scale.

Physical Properties

Crystal structure of lithium, a = 351 pm Lithium is a silver-white, soft light metal. It is the lightest of all solid elements at room temperature (density 0,534 g / cm3). Only solid hydrogen at -260 ° C is even lighter with a density of 0,0763 g / cm3.

Lithium, like the other alkali metals, crystallizes in a cubic-body-centered spherical packing in the space group Im3m (space group number 229) with the lattice parameter a = 351 pm and two formula units per unit cell. At low temperatures of 78 K, the crystal structure changes spontaneously into a hexagonal structure of the magnesium type with the lattice parameters a = 311 pm and c = 509 pm or after deformation into a cubic structure of the copper type (cubic face centered) with the lattice parameter a = 438 pm um. The exact causes of which structure is formed are unknown.

Lithium has the highest melting and boiling point and the highest specific heat capacity among the alkali metals. Although lithium has the highest hardness of all alkali metals, it can still be cut with a knife at a Mohs hardness of 0,6. As a typical metal, it is a good current (conductivity: about 18% of copper) and heat conductor.

Lithium is largely similar to magnesium, which is also reflected in the fact of the appearance of heterotypic mixed crystals of lithium and magnesium, the so-called isodimorphism. Although magnesium crystallizes in the hexagonally dense, while lithium crystallizes in the cubic body-centered spherical packing, both metals are largely hetero-miscible. However, this occurs only in a limited concentration range, with the excess component of the other "impelling" its crystal lattice.

The lithium ion has the highest enthalpy of hydration of all alkali metal ions with -520 kJ / mol. As a result, it is completely hydrated in water and strongly attracts the water molecules. The lithium ion forms two hydration shells, an inner one with four water molecules strongly bound to the lithium ion through its oxygen atoms, and an outer shell in which other hydrogen molecules are connected to the Li [H2O] 4 + ion through hydrogen bonding. As a result, the ionic radius of the hydrated ion is very large, even greater than those of the heavy alkali metals rubidium and cesium, which in aqueous solution do not have such strongly bound hydration shells.

Lewis formula of dilithium

As a gas, lithium is present not only in single atoms, but also molecularly as dilithium Li2. The monovalent lithium thereby achieves a full s-atomic orbital and thus an energetically favorable situation. Dilithium has a bond length of 267,3 pm and a binding energy of 101 kJ / mol. In the gaseous state about 1% (to mass) of the lithium is present as dilithium.

Chemical properties

Lithium is - like all alkali metals - very reactive and readily reacts with many elements and compounds (such as water) with heat release. Among the alkali metals, however, it is the least reactive. A peculiarity that distinguishes lithium from the other alkali metals is its reaction with molecular nitrogen to lithium nitride, which occurs slowly at room temperature:

This is made possible by the high charge density of the Li + ion and thus by a high lattice energy of the lithium nitride. With -3,04 V, lithium has the lowest normal potential in the periodic table and is therefore the least noble of all elements.

Like all alkali metals, lithium is stored under petroleum or paraffin oil, otherwise it reacts with oxygen and nitrogen in the air.

Since the ionic radii of Li + and Mg2 + ions are comparably large, there are also similarities in the properties of lithium or lithium compounds and magnesium or magnesium compounds. This similarity in the properties of two elements from adjacent groups of the periodic table is known as an oblique relationship in the periodic table. Thus, unlike sodium, lithium forms many organometallic compounds (organolithium compounds), such as butyllithium or methyllithium. Similar relationships also exist between beryllium and aluminum as well as between boron and silicon.

isotope

In nature, the two stable isotopes 6Li (7,6%) and 7Li (92,4%) occur. In addition, unstable isotopes, starting with 4Li via 8Li to 12Li, are known, which can only be manufactured artificially. Their half-lives are all in the millisecond range.

6Li plays an important role in nuclear fusion technology. It is used in the nuclear fusion reactor as well as in the hydrogen bomb as a starting material for the production of tritium, which is required for the energy-supplying fusion with deuterium. Tritium is formed in the blanket of the fusion reactor or in the hydrogen bomb next to helium by bombardment of 6Li with neutrons generated during fusion, after the nuclear reaction

The likewise possible reaction

is less suitable (see Blanket). The separation can be carried out, for example, via an isotopic exchange of lithium amalgam and a dissolved lithium compound (such as lithium chloride in ethanol). Yields of about 50% are achieved.

If 6Li is present in a three-stage bomb next to 7Li (as was the case with Castle Bravo, for example), it will react with some of the fast neutrons generated during the merger. This again creates neutrons, helium and additional tritium. As a result, although the 7Li neutron reaction initially consumes energy, this results in increased energy release from additional fusions and more nuclear fission bombardment from uranium. The explosive force is therefore higher than if only the 6Li portion of the isotopic mixture had been converted in the bomb. Since it was assumed before the Castle Bravo test that 7Li would not react with the neutrons, the bomb was about 2,5 times as strong as expected.

The lithium isotope 7Li is produced in small quantities in nuclear power plants by a nuclear reaction of the (used as neutron absorber) Borisotops 10B with neutrons.

The isotopes 6Li, 7Li are both used in experiments with cold quantum gases. Thus, the first Bose-Einstein condensate was produced with the (boson) isotope 7Li. 6Li, on the other hand, is a fermion, and in the year 2003 succeeded in turning molecules of this isotope into a superfluid.

Usage

• lithium battery
• Lithium-ion battery
• Lithium battery and lithium-ion battery.

The most important and fastest growing application for lithium today is the use in lithium-ion batteries (often referred to as rechargeable batteries), the z. As in smartphones, laptops, cordless tools or electrically powered vehicles, such as hybrid cars, electric cars or e-bikes are used (see diagram right). The majority of the lithium salts produced is not reduced to the metal, but used either directly as lithium carbonate, lithium hydroxide, lithium chloride, lithium bromide or converted to other compounds. The metal is needed only in some applications. The main uses of lithium compounds can be found in the "Compounds" section.

Metal

Part of the lithium metal produced is used to recover lithium compounds that can not be made directly from lithium carbonate. These are primarily organic lithium compounds such as butyllithium, lithium-hydrogen compounds such as lithium hydride (LiH) or lithium aluminum hydride and lithium amide.

Lithium is used to remove it from gases because of its ability to react directly with nitrogen.

Metallic lithium is a very strong reducing agent; It reduces many substances that do not react with other reducing agents. It is used in the partial hydrogenation of aromatics (Birch reduction). In metallurgy it is used for the desulfurization, deoxidation and decarburization of molten metals.

Since lithium has a very low normal potential, it can be used in batteries as an anode. These lithium batteries have a high energy density and can generate a particularly high voltage. Not to be confused are the non-rechargeable lithium batteries with the rechargeable lithium-ion batteries, in which lithium metal oxides such as lithium cobalt oxide as a cathode and graphite or other lithium ion-storing compounds are connected as an anode.

 

Alloy component

Lithium is alloyed with some metals to improve their properties. Often even small amounts of lithium are enough for this. As an admixture, it improves the tensile strength, hardness and elasticity of many fabrics. An example of a lithium alloy is sheet metal, a lead alloy containing about 0,04% lithium, which is used as a bearing material in railroads. Even with magnesium-lithium alloys and aluminum-lithium alloys, the mechanical properties are improved by the addition of lithium. At the same time, lithium alloys are very light and are therefore used a lot in aerospace engineering.

Research (atomic physics)

Lithium is often used in atomic physics because it is the only alkali metal with a stable fermionic isotope, making it suitable for investigating effects in ultracold fermionic quantum gases (see BCS theory). At the same time it has a very broad Feshbach resonance, which makes it possible to adjust the scattering length between the atoms at will, the magnetic fields due to the width of the resonance need not be kept very precise.

Medicine

Already 1850 was first used in western medicine as a remedy for gout. However, it proved to be ineffective. Other approaches to the medical use of lithium salts, including as a remedy for infectious diseases, were unsuccessful.

Only 1949 described the Australian psychiatrist John Cade (1912-1980) a possible application for lithium salts. He had injected various chemical compounds, including lithium salts, into guinea pigs, causing them to respond less to external stimuli, becoming calmer, but not drowsy. In retrospect, it was found that the effect observed in the experimental animals was due to intoxication. Following a self-experiment by Cade, 1952-1954 investigated the use of lithium carbonate as a drug to treat manic-depressive patients in a double-blind study at the Psychiatric Hospital in Risskov, Denmark. This laid the foundation for lithium therapy.

In this lithium is used in the form of salts, such as lithium carbonate, against bipolar affect disorders, mania, depression and cluster headache. The small therapeutic range, which lies between 0,6 mmol / l and 1,1 mmol / l, should be taken into account. Already when the lithium blood level moves at the upper limit of the therapeutic width, manageable, reversible side effects can occur in sensitive people. However, if the lithium blood level is well above the therapeutic range - ie above 1,1 mmol / l - the risk of significant to severe side effects such as tremor, rigidity, nausea, vomiting, cardiac arrhythmia and leukocytosis increases rapidly. Over 3,0 mmol / l there is danger to life. The reason is that the metabolism of lithium and sodium is similar. Excessive lithium levels can be caused by sweating or sodium-draining drugs (natriuretic diuretics) with decreasing sodium levels. The body tries to compensate for the sodium loss by removing sodium from the primary urine in the kidneys and transporting it back into the blood (sodium retention). Besides sodium, it also contains lithium, which is normally excreted by the kidneys. The result is an elevated lithium level, which, when taken with lithium, results in drug monitoring that regularly determines the lithium level and adjusts the dose accordingly. Even with the correct dosage, long-term treatment with lithium can lead to water and sodium losses (diabetes insipidus), hyperacidity of the blood (acidosis) and lithium nephropathy with impairment of renal function.

A study released in the US by 1990 describes a significant reduction in offenses and suicides in regions with elevated levels of lithium in drinking water.

The mode of action of lithium as a psychotropic substance has not yet been adequately researched. In particular, influencing the inositol metabolism by inhibiting the myo-inositol 1 phosphatase (enzyme class 3.1.3.25) and the inhibition of glycogen synthase kinase 3 (GSK-3) in nerve cells are currently discussed as possible mechanisms. The antidepressant effect of lithium is probably also due to an increase in serotonergic neurotransmission, ie an increased secretion of serotonin in the synapses, while the antimanic effect is explained by an inhibition of dopaminergic receptors. Another interesting effect of lithium salts on humans and mammals such as rats is the related change in circadian rhythm. This effect could even be detected in plants such as Kalanchoe. Other serotonergic substances such as LSD, mescaline and psilocybin also show such effects in humans. Lithium has been used in animal experiments with Drosophila melanogaster to combat symptoms of Alzheimer's disease - such as forgetfulness.

Age researcher Michael Ristow showed 2011 a possible relationship between the content of lithium in the environment and the life expectancy of a person: in a Japanese population study there was then a statistically significant relationship between a higher content of the trace element and a longer life expectancy; Furthermore, high lithium concentrations prolonged the life expectancy of the model organism Caenorhabditis elegans.

proof

Lithium compounds show a crimson flame coloration, the characteristic spectral lines are the main lines in 670,776 and 670,791 nm; smaller lines are at 610,3 nm. In addition, lithium can be detected by means of flame photometry.

Quantitative detection by wet-chemical methods is difficult because most lithium salts are readily soluble. One possibility is the precipitation of the poorly soluble lithium phosphate. For this purpose, the sample to be examined, for example, made alkaline with sodium hydroxide solution and mixed with some disodium hydrogen phosphate Na2HPO4. Upon heating, a white precipitate precipitates in the presence of Li +:

Another possibility is the use of the iron periodate reagent.

Statements

Elemental lithium in the form of metal dust ignites in the air even at normal temperature.nFor this reason, metallic lithium must also be stored under exclusion of air, usually in petroleum. At higher temperatures from 190 ° C on contact with air immediately predominantly lithium oxide is formed. In pure oxygen, lithium ignites from about 100 ° C. In a pure nitrogen atmosphere, lithium reacts faster to lithium nitride only at higher temperatures. Lithium can react explosively when in contact with substances containing oxygen or halogen.

Since lithium reacts strongly exothermic with common fire extinguishing agents such as water, carbon dioxide, nitrogen or the now prohibited carbon tetrachloride, fires with inert gases such. Argon or other metal firefighting agents such as salt (eg NaCl).

Elemental lithium, like all alkali metals, causes skin burn damage or alkaline burns, as it forms lithium hydroxide with water with heavy heat release; just enough for the skin moisture.

Connections

Lithium is very reactive and forms compounds with most non-metals in which it always exists in the oxidation state + I. These are usually ionic in structure, but in contrast to compounds of other alkali metals have a high covalent share. This is reflected, inter alia, in the fact that many lithium salts - in contrast to the corresponding sodium or potassium salts - are readily soluble in organic solvents such as acetone or ethanol. There are also covalent organic lithium compounds. Many lithium compounds are similar in their properties due to the similar ionic radii of the corresponding magnesium compounds (oblique relationship in the periodic table).

Important reactions of lithium

Hydrogen compounds

Hydrogen forms hydrides with lithium. The simplest lithium-hydrogen compound lithium hydride LiH is formed from the elements at 600-700 ° C. It is used as a rocket fuel and for the rapid recovery of hydrogen, for example for inflating lifejackets. There are also more complex hydrides such as lithium borohydride LiBH4 or lithium aluminum hydride LiAlH4. The latter is of great importance in organic chemistry as a selective hydrogen donor, for example for the reduction of carbonyl and nitro compounds.

Lithium deuteride (LiD) and lithium tritide (LiT) play an important role in nuclear fusion research. Since pure lithium deuteride reduces the energy of the hydrogen bomb, a mixture of LiD and LiT is used. These solid substances are easier to handle than tritium with its high rate of effusion.

 

oxygen compounds

With oxygen, lithium forms both lithium oxide Li2O and lithium peroxide Li2O2.

When lithium reacts with water, lithium hydroxide forms, a strong base. Lithium hydroxide is used to make lithium fats, which are used as greases for cars. Since lithium hydroxide also binds carbon dioxide, it serves to regenerate the air in submarines.

 

Other lithium compounds

• lithium chloride
• lithium carbonate
• Lithium forms salts of the form LiX with the halides. These are lithium fluoride, lithium chloride, lithium bromide and lithium iodide.
• Since lithium chloride is very hygroscopic, it is also used as a desiccant, except as a starting material for lithium production. It is used to dry gases, such as natural gas, before it is piped or in air conditioners to reduce the humidity (to 2% relative humidity). Lithium chloride also serves to reduce melting temperatures, in welding and brazing baths and as a welding electrode sheath for the welding of aluminum. Lithium fluoride is used as a single crystal in infrared spectroscopy.
• The most technically important lithium compound is the poorly soluble lithium carbonate. It is used to recover most other lithium compounds and is used as a flux in the glass industry and in the production of enamel. Also in aluminum production it is added to improve the conductivity and viscosity of the melt.
• Lithium soaps are lithium salts of fatty acids. They are mainly used as thickeners in high-quality mineral oil-based lubricating greases and waxes as well as for the production of pencils.

Further lithium salts are:

• Lithium perchlorate LiClO4,
• Lithium sulphate Li2SO4,
• Lithium nitrate LiNO3, is used with potassium nitrate in the rubber industry for vulcanization,
• Lithium nitride Li3N, formed during the reaction of lithium with nitrogen,
• Lithium niobate LiNbO3, is transparent in a wide wavelength range and is used in optics and for lasers,
• Lithium amide LiNH2, is a strong base and is formed in the reaction of lithium with liquid ammonia.
• Lithium stearate C18H35LiO2, is an important additive for oils in order to use them as lubricating greases. These are used in automobiles, roller mills and agricultural machinery. Lithium stearates are very sparingly soluble in water, so the lubricating film is retained when they come into contact with little water. The lubricating greases obtained have excellent temperature stability (> 150 ° C) and remain lubricious down to −20 ° C.
• Lithium acetate C2H3LiO2
• Lithium citrate C6H5Li3O7
• Lithium hexafluorophosphate LiPF6 is used as conductive salt in lithium-ion batteries.
• Lithium phosphate Li3PO4, is used as a catalyst for the isomerization of propylene oxide.
• Lithium metaborate LiBO2 and lithium tetraborate Li2B4O7
• Lithium bromide LiBr is a reagent for the production of pharmaceuticals, but it is also used in absorption refrigeration systems.

 

Organic lithium compounds

In contrast to most other alkali metal organyls, lithium organyls play a significant role, especially in organic chemistry. Of particular importance are n-butyllithium, tert-butyllithium, methyllithium and phenyllithium, which are also commercially available in the form of their solutions in pentane, hexane, cyclohexane or optionally diethyl ether. It can be prepared by direct reaction of metallic lithium with alkyl / aryl halides according to

or by transmetallation, for example from mercury organyls according to

manufacture.

With elemental lithium in tetrahydrofuran (THF) instead of magnesium in diethyl ether, Grignard-analogous addition reactions of alkyl halides to carbonyl compounds can be carried out with usually better yields.

Due to the clear covalent nature of the structure of lithium organyls is rarely described by a simple Li-C bond. There are usually complex structures, constructed of dimeric, tetrameric or hexameric units, or polymeric structures. Lithium organyls are highly reactive compounds that partially self-ignite in the air. They react explosively with water. Due to their extreme basicity, they also react with solvents whose bound hydrogen is hardly acidic, such as THF, which severely restricts the choice of suitable solvents. Reactions with them are only possible under protective gas and in dried solvents. Therefore, some experience is required in dealing with them and great caution is required.

Another group of organic lithium derivatives are lithium amides of the type LiNR2, of which in particular lithium diisopropylamide (LDA) and lithium bis (trimethylsilyl) amide (LiHMDS, see also HMDS) are used as strong bases without nucleophilic activity.

Lithium organyls are widely used, such as initiators for the anionic polymerization of olefins, as metallating, deprotonating or alkylating agents.

Of some importance are the so-called Gilman cup rates of the type R2CuLi.

 

Lithium price

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