Lithium

Lithium is an alkali metal. It is silvery white in color. When burned, it gives off a crimson glow. Lithium occurs in nature only in compound form. The story of lithium's discovery began in 1800 with a report by a Brazilian scientist named Jose Bonifacio de Andrada e Silvio. He discovered two metals while traveling in Sweden and called them "spodumene" and "petalite." These two metals were rediscovered by a Swedish chemist, E. T. Svenenstjema. Investigation of the metals was puzzling, because anywhere from one to ten percent of the components was unaccounted for during chemical analysis.

Arfvedson's Studies Lead to Discovery

The explanation for this problem was provided by Johan August Arfvedson, a young man working in the laboratory of Jons Berzelius. The components Arfvedson identified in the mineral added up to 95 or 105 percent, but never 100 percent. He concluded that these results could be explained only by the presence of a new element in the mineral. He proposed the name "lithium" for the new element, which comes from the Greek word "lithos," or "stone."

Arfvedson was never able to isolate the pure metal itself. That was accomplished by W. T. Brande (1788-1866) and Humphry Davy (1778-1829) working independently in 1818. The men obtained the metal through electrolysis of lithium oxide. By 1855, Bunsen and Matthiessen had discovered a way to produce the metal in large quantities and could manufacture a few grams of it in a matter of minutes.

Researchers soon found lithium in both plants and animals, although only in small amounts. In 1860, Gustav Kirchhoff and Bunsen found lithium in the ash of grapes, tobacco, kelp, and in milk. Later, researchers also found the element in human urine, bones, and teeth.

Medical Uses

A number of lithium compounds have important pharmacological effects. Lithium carbonate is the most commonly used of the compounds. In the early nineteenth century, these compounds were used to treat gout (an illness characterized by a painful swelling of the joints), and lithium bromide was used to induce sleep.

In 1949, J. F. J. Cade of Australia was looking for toxic (poisonous) nitrogenous substances in the urine of mental patients by testing guinea pigs. He administered lithium salts to the animals in an attempt to increase the solubility of urates so that they would be secreted more readily in the urine. Lithium carbonate, one of the salts, made the animals sleepy. He then gave lithium carbonate to severely agitated or manic patients. He reported that this treatment seemed to have a dramatic effect on mania.

Lithium carbonate was not accepted for use in the United States until 1970, however, owing to fears about its safety. These fears existed because doctors in the 1940s had used lithium chloride as a salt substitute in heart patients and others who were chronically ill. This was ill-advised and led to severe toxicities (poisonous reactions) and death.

Today lithium carbonate successfully controls the wild mood swings from depression to elation observed in manic-depressive illness (also known as bipolar disorder). It produces the most dramatic therapeutic improvement of any drug used in psychiatry.

lithium [Gr.,=stone], metallic chemical element; symbol Li; at. no. 3; interval in which at. wt. ranges 6.938–6.997; m.p. about 180.54°C; b.p. about 1,342°C; sp. gr. .534 at 20°C; valence +1. Lithium is a soft, silver-white metal. It is one of the alkali metals in Group 1 of the periodic table . It is the least dense metal. Because it has high specific heat, it has found some use in cooling systems for nuclear reactors; such use is limited because lithium is very corrosive. Lithium metal is prepared by electrolysis of fused lithium chloride. Lithium reacts with water less readily than sodium. It burns in air with a brilliant white flame. Lithium forms many inorganic compounds, among them a hydride (LiH), a nitride (Li ₃ N), an oxide (lithia, Li ₂ O), a hydroxide (LiOH), a carbide (Li ₂ C ₂ ), a carbonate (Li ₂ CO ₃ ), and a phosphate (Li ₃ PO ₄ ). When heated it reacts directly with the halogens to form halides. Lithium aluminum hydride (LiAlH ₄ ) is an important reagent in organic chemistry. Lithium also forms numerous organic compounds. One compound of major importance is lithium stearate, produced by cooking tallow (or other animal fat) with lithium hydroxide; lithium stearate is used to transform oil into lithium-base lubricating greases, which have found extensive use in the automotive industry. Lithium carbonate is used in special glasses and ceramic glazes. Lithium chloride and bromide are used as brazing and welding fluxes; they are also used in air conditioning systems because they are very hygroscopic, i.e., they absorb moisture. Lithium hydroxide is used to increase the capacity of alkaline storage cells. Lithium compounds are used in the nuclear energy industry, in the preparation of plastics and synthetic rubber, and in the synthesis of vitamin A. Lithium is added in small amounts to magnesium, aluminum, or lead-base alloys; it is also used as a degasifier in iron, steel, and copper refining. In addition, lithium is used to scavenge small amounts of oxygen and nitrogen in electronic vacuum tubes. Trace amounts of lithium and its compounds color a flame bright red; they are used in pyrotechnics. Lithium in the salt form has recently come into use as a medical treatment for bipolar disorder. Lithium is widely distributed in nature; it is found in the soil, in plants, in animals, and in the human body. It is also found in the sun. Lithium may be profitably extracted from ores containing as little as 1% lithium (measured as lithium oxide). Some commercially important minerals are lepidolite, petalite, spodumene, and amblygonite. Lithium is also produced from brines such as those in Searles Lake, Calif., and in the Great Salt Lake, Utah. Lithium was discovered in 1817 by J. A. Arfvedson.

Lithium

melting point: 180.5°C
boiling point: 1,342°C
density: 0.534 g/cm ³
most common ions: +1

Lithium is a soft, silvery alkali metal and has the lowest density of any metal. The word "lithium" is derived from "lithos" (Greek for "stone"). Johan A. Arfvedson discovered lithium in Stockholm, Sweden, in 1817. Humphry Davy isolated it via electrolysis in 1818. Currently, lithium metal is generated by the electrolysis of a molten mixture of lithium chloride, LiCl, and potassium chloride, KCl. In nature it is never found in its elemental form. Its main sources are the minerals spodumene, petalite, lepidolite, and amblygonite. Lithium's average crustal abundance is about 18 ppm. It has the highest specific heat of any solid element and is the least reactive alkali metal toward water. Lithium burns crimson in the flame test.

Metallic lithium has a variety of uses. It is used as an anode material in batteries and as a heat transfer agent. Magnesium-lithium alloys are used to produce armor plate and aerospace materials, while aluminum-lithium alloys find applications in the aircraft industry. Lithium is also used to produce chemical reagents such as LiAlH₄ (a reducing agent ) and n -butylithium (a strong base).

Compounds of lithium are also economically important. Air conditioning systems use LiCl and LiBr because they are very hygroscopic and readily absorb water from the air. Thermonuclear weapons incorporate lithium deuteride, LiD. Lithium stearate is obtained by treating tallow with lithium hydroxide, LiOH, and is used as a thickener that imparts high temperature resistance to lubricants. Carbon dioxide removal systems in submarines and spacecraft use LiOH. Lithium carbonate, Li₂CO₃, is used to increase the electrical current flow in the electrolytic production of aluminum from bauxite and to strengthen glasses by substituting for sodium ions. Although lithium carbonate has been used to treat bipolar (manic-depressive) disorder since 1949, its mechanism of operation is still not completely understood.

see also Alkali Metals; Davy, Humphry.

Nathan J. Barrows

Bibliography

Emsley, John (2001). Nature's Building Blocks: An A–Z Guide to the Elements. New York: Oxford University Press.

Greenwood, Norman N., and Earnshaw, A. (1997). Chemistry of the Elements, 2nd edition. Boston: Butterworth-Heinemann.

Lide, David R., ed. (2000). The CRC Handbook of Chemistry & Physics, 81st edition. New York: CRC Press.

lithium (symbol Li) Common, silvery metallic element, one of the alkali metals, first isolated in 1817. Ores include lepidolite and spodumene. Chemically, it is similar to sodium. Lithium, the lightest of all metals, is used in alloys, glasses and glazes; its salts are used in medicine. Properties at.no. 3; r.a.m. 6.941; r.d. 0.534; m.p. 180.5°C (356.9°F); b.p. 1347°C (2456.6°F); most stable isotope Li⁷ (92.58%).

lithium (lith-iŭm) n. a drug given by mouth in the form of lithium carbonate or lithium citrate for the prevention and treatment of episodes of mania or recurrent depression in patients with bipolar affective disorder. Thyroid function can be impaired after many years of use and regular thyroid function tests are compulsory. Trade names: Priadel, etc.

lith·i·um / ˈli[unvoicedth]ēəm/ • n. the chemical element of atomic number 3, a soft silver-white metal. It is the lightest of the alkali metals. (Symbol: Li) ∎  lithium carbonate or another lithium salt, used as a mood-stabilizing drug.

lithium Metal not known to have any physiological function, although it occurs in food and water; lithium salts are used in the treatment of manic‐depressive illness.

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