Lithium

Properties

History

Treatment

John Cade

Administration

Resources

Lithium—which has the highest specific heat of any solid element—is the first element in Group 1 of the periodic table, a group of elements generally known as the alkali metals. It is the lightest of all metals. Lithium’s atomic number is 3, its atomic mass is 6.941, and its chemical symbol is Li.

Properties

Properties Lithium is a very soft, silvery metal with a melting point of about 356.97°F (180.54°C), a boiling point of 2,435°F (1,335°C), and a density of 0.308 ounces per cubic inch (0.534 grams per cubic centimeter). It is a solid at room temperature. Lithium is extraordinarily soft for a metal with a rating of 0.6 on the Mohs scale, softer even than talc, whose Mohs rating is 1.

Lithium is an active metal, although, as one would predict from its placement in the periodic table, is not as active as sodium, potassium, and the other alkali metals. For example, it reacts slowly with cold water, releasing hydrogen gas. It does not react with oxygen at room temperature, although it does react at higher temperatures to form lithium oxide (LiO₂). Under the proper conditions, the element also reacts with sulfur, hydrogen, nitrogen, and the halogens.

Lithium is about the 15th most abundance element in the Earth’s crust with an abundance of about 0.005%. Its estimated crustal abundance is 3.2 x 10^-4 ounces per pound (2.0 x 10¹ milligrams per kilogram) and its estimated oceanic abundance is 2.4 x 10^-5 ounces per gallon (1.8x10^-1 milligrams per liter. Lithium never occurs as a free element, but it is found in minerals such as spodumene, petalite, and lepidolite. Some lithium is also found in seawater, primarily as dissolved lithium chloride (LiCl). The world’s largest producer of lithium is the United States, followed by the countries of Australia, Russia, Canada, Zimbabwe, Chile, and China. In the United States, lithium is produced at three large mines in Nevada and North Carolina.

The first step in extracting lithium from its ores is to convert the ore to lithium chloride, which is then electrolyzed to obtain the pure element: 2LiCl— electric current←→ 2Li + Cl₂.

History

The use of lithium for medicinal purposes can be traced back over 1,800 years to Greek physician Galen, who treated patients with mania by having them bathe in alkaline springs and drink the water,which probably contained lithium. In 1817, Swedish chemist August Arfwedson (or Arfvedson; 1792–1841), described the element lithium, which he named from the Greek word that means stone. Arfwedson was not able to prepare pure lithium because it was too active. That step was accomplished about a year later by the Swedish chemist William Thomas Brande (1788–1866) and the English chemist Sir Humphry Davy (1778–1829), both of whom used a method similar to the one employed today for extracting lithium from lithium chloride by electrolysis.

In the 1840s, lithium was mixed with carbonate or citrate to form a salt and was used to treat gout, epilepsy, diabetes, cancer, and sleeplessness. None of these treatments were effective, but interest in lithium as a medicine continued. In the 1940s, lithium chloride was administered as a salt substitute for patients requiring low-salt diets. This proved to be dangerous because an insufficient amount of sodium in the body causes lithium to build up. Too much lithium can cause poisoning and even death if the levels become too high.

Treatment

Lithium has been the treatment of choice for bipolar disorder (formerly called manic-depressive illness) for several decades. Lithium is a trace element found in plants, mineral rocks, and in the human body. Today, the major source of medical lithium is mines in North Carolina. Lithium is classified as an antimonic medication because of its ability to reverse mania, a mood disorder characterized by extreme excitement and activity. In addition, lithium is also effective in reversing deep depression, the other mood extreme of bipolar disorder, and in decreasing the frequency of manic and depressive cycles in patients.

While there has been a great deal of success in treating bipolar patients with lithium and returning them to a normal life, researchers are not exactly sure how it works. It is a non-addictive and non-sedating medication, but its use must be carefully monitored for possibly dangerous side effects. For some patients suffering from some symptoms of schizophrenia, lithium may be used in combination with other medications. Lithium is also used to treat people who suffer from unipolar depression.

Before lithium was in general use for the treatment of bipolar disorder, as many as one in five patients with this condition committed suicide. Many who suffered from this illness were never able to live normal, productive lives. Lithium therapy now allows many people with bipolar disorder to participate in ordinary everyday life. Seventy to 80% of bipolar patients respond well to lithium treatment without any serious side effects.

John Cade

The story of lithium parallels other stories in medical history where the medicinal value of a substance is discovered accidentally. In 1949, John Cade, an Australian psychiatrist, decided to experiment with lithium on guinea pigs. He theorized that uric acid was a cause of manic behavior. Since he needed to keep the uric acid soluble, he used lithium salts as an agent in the solution. The guinea pigs did not become manic as he expected, but instead they responded by becoming extremely calm.

When Cade used the lithium treatment on 10 manic patients, he reported remarkable improvement in the patients’ condition. One patient who had been in a manic state for five years was able to leave the hospital after a three-month treatment and resume a normal life. Cade reported his results in the Medical Journal of Australia, but his findings did not have an impact on the medical community at that time.

When Cade carried out his experiments, reports of lithium poisonings were widespread in the United States. It was not until the work of Mogens Schou, who campaigned for recognition of lithium as a treatment for bipolar disorfder, that acceptance of lithium began. In the United States, however, it did not gain full FDA (Federal Drug Administration) approval until 1974, although trials were conducted during the 1960s.

Administration

The dosage of lithium must be regulated on an individual basis. The level of concentration in the blood must be approximately between 0.8 to 1.4 milli-equivalents per liter of blood. For this reason, blood samples must be taken regularly when a person is receiving lithium treatment. When the concentration of lithium is too low, the desired results will not be obtained and if it is too high, there may be adverse side effects.

Initially, the dose given is very low, then a blood sample is taken, and the dosage is increased gradually until the desired concentration is reached. When therapy is initiated, blood samples are taken every three or four days, then once a week, progressing to every two weeks, once a month, then perhaps every three or four months. In order to maintain the desired level, the medication is usually taken periodically throughout the day, depending upon the dosage. Slow-release and sustained-release tablets and capsules have been developed that make the administration of lithium medication easier. It is sometimes taken in liquid form as well.

KEY TERMS

Bipolar disorder —Manic-depressive illness, a condition where the patient exhibits both an excited state called mania and a depressed state.

Electroconvulsive therapy (ECT)

—Administration of a low dose electric current to the head in conjunction with muscle relaxants to produce convulsions. A treatment method whose underlying action is still not fully understood, it has proven effective in relieving symptoms of some severe psychiatric disorders for which no other treatment has been effective, for example, severe depression.

Schizophrenia —A mental illness characterized by thought disorder, distancing from reality, and sometimes delusions and hallucinations.

Unipolar depression —A mental illness in which the patient suffers from depression only.

Precautions

Lithium is absorbed quickly into the bloodstream and carried to all tissues of the body and brain. It is excreted through the kidneys. Because sodium is also passed out through the kidneys and affects lithium secretion, a normal sodium balance is necessary to maintain a lithium balance as well. If there is an insufficient amount of sodium in the body, the lithium builds up and can become toxic.

Besides avoiding a low-salt diet, patients receiving lithium therapy for bipolar disorder are cautioned to drink alcohol in moderation and to discuss all over-the-counter and prescription medicine with their psychiatrists, since some antibiotics and anti-inflammatory agents like ibuprofen can increase lithium levels in the bloodstream. The use of lithium during pregnancy presents certain risks. Electroconvulsive therapy (ECT) is sometimes recommended for pregnant patients who have been taking lithium as treatment for bipolar disorder. Older persons on lithium and low-salt diets must also be cautious.

Possible side effects of lithium therapy are stomach ache, nausea, vomiting, diarrhea, hand tremors, thirst, fatigue, and muscle weakness. Some patients report weight gain while on lithium and a thyroid condition may develop, but can be easily treated with thyroid replacement hormones.

By and large, lithium treatment has been an effective drug for patients suffering from bipolar disorder. Many remain in treatment for extended periods of time without any harmful side effects, and most importantly, are able to lead normal and productive lives without hospitalization.

See also Antipsychotic drugs; Bipolar disorder.

Resources

BOOKS

Akiskal, Hagop S., and Mauricio Tohen, eds. Bipolar Psychopharmacotherapy: Caring for the Patient. Chichester, UK, and Hoboken, NJ: John Wiley & Sons, 2006.

Bauer, Michael, Paul Grof, Bruno Muller-Oerlinghausen, eds. Lithium in Neuropsychiatry: The Comprehensive Guide. Abingdon, UK: Informa Healthcare, 2006.

Emsley, John. Nature’s Building Blocks: An A-Z Guide to the Elements. Oxford, UK: Oxford University Press, 2003.

Schou, Mogens. Lithium Treatment of Mood Disorders:A Practical Guide. Basel, Switzerland, and New York: Karger, 2004.

Siekierski, Slawomir. Concise Chemistry of the Elements. Chichester, UK: Horwood Publishing, 2002.

Yatham, Lakshmi N., Vivek Kusurnakar, Stanley P. Kutcher, eds. Bipolar Disorder: A Clinician’s Guide to Biological Treatments. New York: Brunner-Routledge, 2002.

PERIODICALS

Dinan, Timothy G. “Lithium in Bipolar Mood Disorder.” British Medical Journal 324, no. 7344 (2002): 989.

Sajatovic, M. “Treatment of Bipolar Disorder in Older Adults.” International Journal of Geriatric Psychiatry 17, no. 9 (2002): 865-873.

Vita Richman

LITHIUM (REVISED)

Note: This article, originally published in 1998, was updated in 2006 for the eBook edition.

Overview

Lithium is the first member of the alkali metal family. The alkali metals are the elements that make up Group 1 (IA) of the periodic table. The periodic table is a chart that shows how chemical elements are related to one another. The alkali metals include sodium, potassium, rubidium, cesium, and rancium. Lithium is also the least dense of all metals. It has a density about half that of water.

Credit for the discovery of lithium usually goes to Swedish chemist Johan August Arfwedson (or Arfvedson; 1792-1841). Arfwedson found the new element in a mineral that had first been identified about twenty years earlier by Brazilian scientist Jozée Bonifácio de Andrada e Silva (1763-1838). That mineral, petalite, is still a major source of lithium today.

Lithium has a number of important and interesting uses. In recent years, it has been used to make lightweight, efficient batteries. Compounds of lithium have also been used to treat a mental disorder known as bipolar disorder.

SYMBOL
Li

ATOMIC NUMBER
3

ATOMIC MASS
6.941

FAMILY
Group 1 (IA)
Alkali metal

PRONUNCIATION
LI-thee-um

Discovery and naming

The first clues to the existence of lithium surfaced in 1800. De Andrada was a Brazilian scientist and statesman visiting inScandinavia. During one of his trips to the countryside, he came across a mineral that he did not recognize. He called the mineral petalite.

Some scientists were not convinced that petalite was a new mineral. But in 1817, the same mineral was rediscovered on the island of Utö. Interest in the mineral grew.

Arfwedson was troubled by the results of his analysis of petalite. In his studies, he could not identify 10 percent of the mineral. He finally concluded that the missing 10 percent must be a new element. He called the new element lithium, from the Greek word lithos for "stone."

Arfwedson was not able to produce pure lithium. About a year later, however, Swedish chemist William Thomas Brande (1788-1866) and English chemist Sir Humphry Davy (1778-1829) were both able to extract the pure metal from its compounds. (See sidebar on Davy in the calcium entry in Volume 1.)

Physical properties

Lithium is a very soft, silvery metal. It has a melting point of 180.54°C (356.97°F) and a boiling point of about 1,335°C (2,435°F). Its density is 0.534 grams per cubic centimeter. By comparison, the density of water is 1.000 grams per cubic centimeter. Lithium's hardness on the Mohs scale is 0.6. The Mohs scale is a way of expressing the hardness of a material. It runs from 0 (for talc) to 10 (for diamond). A hardness of 0.6 means that the material can be scratched with a fingernail.

Chemical properties

Lithium is an active element, but not as active as the other alkali metals. It reacts slowly with water at room temperature and more rapidly at higher temperatures. It also reacts with most acids, giving off hydrogen gas. Lithium does not react with oxygen at room temperature, but above 100°C does so to form lithium oxide (Li₂0). Under the proper conditions, the element also combines with sulfur, hydrogen, nitrogen, and the halogens.

Occurrence in nature

The abundance of lithium in the Earth's crust is estimated to be about 0.005 percent. That places it among the top 15 elements found in the earth. The most common ores of lithium are spodumene, petalite, and lepidolite. Lithium is also obtained from saltwater. As saltwater evaporates, dissolved solids are left behind. These solids include sodium chloride (NaCl), potassium chloride (KCl), and lithium chloride (LiCl).

The world's largest producer of lithium is the United States. Three of the largest U.S. mines are located in Silver Peak, Nevada, and Kings Mountain and Bessemer City, North Carolina. Other major producers of lithium compounds are Australia, Russia, Canada, Zimbabwe, Chile, and China.

Isotopes

Two naturally occurring isotopes of lithium exist, Lithium-6 and lithium-7. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element's name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope.

In addition, three radioactive isotopes of lithium have been produced. A radioactive isotope is one that breaks apart and gives off some form of radiation. Radioactive isotopes are produced when very small particles are fired at atoms. These particles stick in the atoms and make them radioactive. None of these isotopes has any important commercial application.

Extraction

Lithium compounds are first converted to lithium chloride (LiCl). Then, an electric current is passed through molted (melted) lithium chloride. The current separates the compound into lithium and chlorine gas:

Uses and compounds

Lithium metal and its compounds have a great many uses. Two of the most significant applications are in the glass and ceramics field and in the production of aluminum. The addition of a small amount of lithium carbonate (Li₂CO₃) to a glass or ceramic makes the material stronger. Examples of the use of lithium carbonate are shock-resistant cookware (such as the Pyrex brand) and black-and-white television tubes. About 40 percent of the lithium used in the United States in 1996 went to these applications.

Lithium carbonate is added to glass to make it stronger. Pyrex cookware is made up of this kind of glass.

Producers of aluminum also use lithium carbonate in preparing aluminum metal from aluminum oxide. Lithium carbonate reduces the heat needed to make the reaction occur. As a result, producers save money by using less energy. In 1996, about 20 percent of all lithium carbonate produced in the United States went to this application.

Another important compound of lithium is lithium stearate. Lithium stearate is added to petroleum to make a thick lubricating grease. The grease is used in many industrial applications because it does not break down at high temperatures, it does not become hard when cooled, and it does not react with water or oxygen in the air. Lithium greases are used in military, industrial, automotive, aircraft, and marine applications. Lithium stearate is also used as an additive in cosmetics and plastics. Overall, the manufacture of lithium stearate is the third most important use of lithium compounds after glasses and ceramics manufacture and aluminum production.

The first commercial use of lithium was in the production of alloys. An alloy is made by melting and mixing two or more metals. The mixture has properties different from those of the individual metals. Early lithium alloys included lead and were used to make tough ball bearings for machinery.

Feeling better with lithium

A n exciting new use for lithium carbonate was discovered in 1949. John Cade (1912-80), an Australian physician, found that patients with bipolar disorder benefitted from taking lithium carbonate. Bipolar disorder is a condition once known as manic-depressive disorder. The condition is characterized by dramatic mood swings. A person can be very happy and carefree one moment, but terribly depressed the next moment. Some patients become so depressed that they commit suicide. Until 1949, there was no effective treatment for bipolar disorder.

Cade found that most patients who took lithium carbonate were relieved of at least some of their symptoms. Their "high" points were not as high, and their "low" points were not as low. The compound helped someone with bipolar disorder to live a quieter, more normal life. Today, more than 60 percent of those with bipolar disorder benefit from lithium treatments.

As with most medications, lithium compounds can have side effects. They can cause nausea, dizziness, diarrhea, dry mouth, and weight gain. But these side effects can usually be controlled. And they are often a small price to pay for relief from the terrible effects of bipolar disorder.

Today, the most commonly used alloys of lithium are made with aluminum or magnesium. These alloys are very light, but very strong. They are used for armor plates and in aerospace applications.

Lithium compounds are also used as catalysts in many different industrial processes. A catalyst is a substance used to speed up or slow down a chemical reaction. The catalyst does not undergo any change itself during the reaction. For example, one lithium catalyst is used to make tough, strong, synthetic (artificial) rubber. It does not have to be vulcanized (heat-treated) like natural rubber.

Lithium has become important in the manufacture of batteries. A battery is a device for converting chemical energy into electrical energy. Car batteries use a chemical reaction between lead and sulfuric acid to make electrical energy.

Lithium batteries are much lighter than lead and sulfuric acid batteries. They also reduce the use of toxic lead and cadmium. Lithium batteries are used in products such as watches, microcomputers, cameras, small appliances, electronic games, toys, and many kinds of military and space vehicles.

Lithium compounds tend to harm the kidneys.

Health effects

Lithium and its compounds have a range of effects on the human body. For instance, compounds of lithium tend to harm the kidneys. And lithium carbonate (Li₂CO₃) can affect a person's mental health (see accompanying sidebar).

Lithium

Lithium has been the treatment of choice for manic-depressive illness for several decades. Lithium is a trace element found in plants, mineral rocks , and in the human body. Today, the major source of medical lithium is mines in North Carolina. Lithium is classified as an antimonic medication because of its ability to reverse mania , a mood disorder characterized by extreme excitement and activity. In addition, lithium is also effective in reversing deep depression , the other mood extreme of manic-depressive illness, and in decreasing the frequency of manic and depressive cycles in patients. Manic-depressive illness is now generally referred to as bipolar disorder, a term preferred in the psychiatric community.

While there has been a great deal of success in treating manic-depressive patients with lithium and returning them to a normal life, researchers are not exactly sure how it works. It is a non-addictive and non-sedating medication, but its use must be carefully monitored for possibly dangerous side effects. For some patients suffering from some symptoms of schizophrenia , lithium may be used in combination with other medications. Lithium is also used to treat people who suffer from unipolar depression.

Before lithium was in general use for the treatment of bipolar disorder, as many as one in five patients with this condition committed suicide. Many who suffered from this illness were never able to live normal, productive lives. Lithium therapy now allows many people with bipolar disorder to participate in ordinary everyday life. Seventy to 80% of bipolar patients respond well to lithium treatment without any serious side effects.

History of use

The use of lithium for medicinal purposes can be traced back 1,800 years to the Greek physician Galen, who treated patients with mania by having them bathe in alkaline springs and drink the water , which probably contained lithium. In 1817, the Swedish chemist, August Arfwedson, described the element lithium, which he named from the Greek word that means stone. It is the lightest of the alkali (soluble salt ) metals. In the 1840s, lithium was mixed with carbonate or citrate to form a salt and was used to treat gout, epilepsy , diabetes, cancer , and sleeplessness. None of these treatments were effective, but interest in lithium as a medicine continued. In the 1940s, lithium chloride was administered as a salt substitute for patients requiring low-salt diets. This proved to be dangerous because an insufficient amount of sodium in the body causes lithium to build up. Too much lithium can cause poisoning and even death if the levels become too high.

John Cade

The story of lithium parallels other stories in medical history where the medicinal value of a substance is discovered accidently. In 1949, John Cade, an Australian psychiatrist, decided to experiment with lithium on guinea pigs. He theorized that uric acid was a cause of manic behavior . Since he needed to keep the uric acid soluble, he used lithium salts as an agent in the solution . The guinea pigs did not become manic as he expected, but instead they responded by becoming extremely calm.

When Cade used the lithium treatment on 10 manic patients, he reported remarkable improvement in the patients' condition. One patient who had been in a manic state for five years was able to leave the hospital after a three-month treatment and resume a normal life. Cade reported his results in the Medical Journal of Australia, but his findings did not have an impact on the medical community at that time.

When Cade carried out his experiments, reports of lithium poisonings were widespread in the United States. It was not until the work of Mogens Schou, who campaigned for recognition of lithium as a treatment for manic-depressive illness, that acceptance of lithium began. In the United States, however, it did not gain full FDA approval until 1974, although trials were conducted during the 1960s.

Administration

The dosage of lithium must be regulated on an individual basis. The level of concentration in the blood must be approximately between 0.8-1.4 milli-equivalents per liter of blood. For this reason blood samples must be taken regularly when a person is receiving lithium treatment. When the concentration of lithium is too low, the desired results will not be obtained and if it is too high, there may be adverse side effects.

Initially, the dose given is very low, then a blood sample is taken, and the dosage is increased gradually until the desired concentration is reached. When therapy is initiated, blood samples are taken every three or four days, then once a week, progressing to every two weeks, once a month, then perhaps every three or four months. In order to maintain the desired level, the medication is usually taken periodically throughout the day, depending upon the dosage. Slow-release and sustained-release tablets and capsules have been developed that make the administration of lithium medication easier. It is sometimes taken in liquid form as well.

Precautions

Lithium is absorbed quickly into the bloodstream and carried to all tissues of the body and brain . It is excreted through the kidneys. Because sodium is also passed out through the kidneys and affects lithium secretion, a normal sodium balance is necessary to maintain a lithium balance as well. If there is an insufficient amount of sodium in the body, the lithium builds up and can become toxic.

Besides avoiding a low-salt diet, patients receiving lithium therapy for bipolar disorder are cautioned to drink alcohol in moderation and to discuss all over-the-counter and prescription medicine with their psychiatrists, since some antibiotics and anti-inflammatory agents like ibuprofen can increase lithium levels in the bloodstream. The use of lithium during pregnancy presents certain risks. Electroconvulsive therapy (ECT) is sometimes recommended for pregnant patients who have been taking lithium as treatment for bipolar disorder. Older persons on lithium and low-salt diets must also be cautious.

Possible side effects of lithium therapy are stomach ache, nausea, vomiting, diarrhea, hand tremors, thirst, fatigue, and muscle weakness. Some patients report weight gain while on lithium and a thyroid condition may develop, but can be easily treated with thyroid replacement hormones .

By and large, lithium treatment has been an effective drug for patients suffering from bipolar disorder. Many remain in treatment for extended periods of time without any harmful side effects, and most importantly, are able to lead normal and productive lives without hospitalization.

See also Antipsychotic drugs; Manic depression.

Resources

books

Bohn, John. Lithium and Manic Depression. Madison, WI: University of Wisconsin, 1990.

Goodwin, Frederick K., and Kay Redfield Jamison. Manic-Depressive Illness. New York: Oxford University Press, 1990.

Jamison, Kay Redfield. Touched with Fire. New York: Free Press, 1993.

Jefferson, James W., and John H. Greist. Lithium and Manic Depression: A Guide. Madison, WI: Madison Institute of Medicine, 1999.

Papolos, Demitri F., and Janice Papolos. Overcoming Depression. New York: Harper & Row, 1987.

Schou, Mogens. Lithium Treatment of Manic-Depressive Illness. 5th rev. ed. New York: Basel, 1993.

periodicals

Dinan, Timothy G. "Lithium in Bipolar Mood Disorder." British Medical Journal 324, no. 7344 (2002): 989.

Sajatovic, M. "Treatment of Bipolar Disorder in Older Adults." International Journal of Geriatric Psychiatry 17, no. 9 (2002): 865-873.

Vita Richman

KEY TERMS

Electroconvulsive therapy (ECT)

—Administration of a low dose electric current to the head in conjunction with muscle relaxants to produce convulsions. A treatment method whose underlying action is still not fully understood, it has proven effective in relieving symptoms of some severe psychiatric disorders for which no other treatment has been effective, for example, severe depression.

Manic-depressive illness

—Bipolar disorder, a condition where the patient exhibits both an excited state called mania and a depressed state.

Schizophrenia

—A mental illness characterized by thought disorder, distancing from reality, and sometimes delusions and hallucinations.

Unipolar depression

—A mental illness in which the patient suffers from depression only.

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

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.