Lithium
|
Background
Lithium, the lightest metal, is in a group of elements called alkali metals or Group I elements and is silvery-white in color. It has the atomic number of 3. The alkali metals group includes lithium (Li), potassium (K), and sodium (Na). The three alkali metals are highly reactive with oxygen and water, so they are stored in oil. Although lithium will react dramatically when put in water, it is the least reactive alkali metal. When it reacts with water it bounces on the top of the water because it is less dense than water.
Johan A. Arfvedson, of Stockholm, Sweden, first discovered lithium in 1817. It was first isolated by W.T. Brande and Humphry Davy in the 19th century, but it was not commercially produced until 1923.
Name
| Previous Element: Helium Lithium Next Element: Beryllium |
| |
| Physical Properties | ||
|---|---|---|
| Color | Silvery | |
| Phase at Room Temp. | solid | |
| Density (g/cm3) | 0.534 | |
| Hardness (Mohs) | .6 | |
| Melting Point (K) | 453.74 | |
| Boiling Point (K) | 1620 | |
| Heat of Fusion (kJ/mol) | 4.6 | |
| Heat of Vaporization (kJ/mol) | 148 | |
| Heat of Atomization (kJ/mol) | 161 | |
| Thermal Conductivity (J/m sec K) | 84.8 | |
| Electrical Conductivity (1/mohm cm) | 107.8 | |
| Source | Spodumene (silicate) | |
| Atomic Properties | ||
| Electron Configuration | [He]2s1 | |
| Number of Isotopes | 2 | |
| Electron Affinity (kJ/mol) | 59.63 | |
| First Ionization Energy (kJ/mol) | 520.2 | |
| Second Ionization Energy (kJ/mol) | 7394.4 | |
| Third Ionization Energy (kJ/mol) | 11814.6 | |
| Electronegativity | 0.98 | |
| Polarizability (Å3) | 24.3 | |
| Atomic Weight | 6.941 | |
| Atomic Volume (cm3/mol) | 13 | |
| Ionic Radius2- (pm) | --- | |
| Ionic Radius1- (pm) | --- | |
| Atomic Radius (pm) | 152 | |
| Ionic Radius1+ (pm) | 90 | |
| Ionic Radius2+ (pm) | --- | |
| Ionic Radius3+ (pm) | --- | |
| Common Oxidation Numbers | +1 | |
| Other Oxid. Numbers | -1 | |
| Abundance | ||
| In Earth's Crust (mg/kg) | 2.0×101 | |
| In Earth's Ocean (mg/L) | 1.8×10-1 | |
| In Human Body (%) | 0.00001 % | |
| Regulatory / Health | ||
| CAS Number | 7439-93-2 | |
| OSHA Permissible Exposure Limit (PEL) | No limits | |
| OSHA PEL Vacated 1989 | No limits | |
| NIOSH Recommended Exposure Limit (REL) | No limits | |
| Sources: University of Wisconsin General Chemistry Mineral Information Institute Jefferson Accelerator Laboratory EnvironmentalChemistry.com | ||
The name lithium comes from the Greek word lithos which means stone because lithium was first discovered in rocks and the other two alkali metals were first discovered in plants. Lithium was first found in the mineral called petalite (LiAl(Si2O5)2, lithium aluminum silicate. Petalite is found in the minerals spodumene, lepidolite mica, and amblygonite.
Sources
Some lithium is recovered from the mineral spodumene. Commercial quantities of spodumene are in a special igneous rock deposit that geologists call a pegmatite. In pegmatites, the liquid rock (magma) cools so slowly that crystals have time to grow very large. The largest spodumene crystal ever found was found in a pegmatite in South Dakota.
Most lithium is recovered from brine, or water with a high concentration of lithium carbonate. Brines trapped in the Earth’s crust (called subsurface brines) are the major source material for lithium carbonate. These sources are less expensive to mine than from rock such as spodumene, petalite, and other lithium-bearing minerals.
It is estimated that the United States has approximately 760,000 tons of lithium. The resources in the rest of the world are estimated to be 12 million tons. The United States is the world’s leading consumer of lithium and lithium compounds. The leading producers and exporters of lithium ore materials are Chile and Argentina. China and Russia have lithium ore resources, but it is presently cheaper for these countries to import this material from Chile than to mine their own.
Uses
More than one-half of the lithium compounds consumed are used in the manufacture of glass, ceramics, and aluminum. Lithium is also used in making synthetic rubber, greases and other lubricants.
Lithium batteries are proving to be an effective and affordable alternative to traditional batteries, and also in new battery applications.
Lithium is mixed with other light metals such as aluminum and magnesium to form strong, light-weight alloys (an alloy is a mixture of metals).
Some lithium, in the form of lithium carbonate or lithium citrate, is used as medicine to treat gout (an inflammation of joints) and to treat serious mental illness.
Substitutes and Alternative Sources
Potassium compounds can be used in glass and ceramic production. Greases can be made using calcium soaps, for example, in place of lithium compounds. In some cases, glass, polymers and resins can be used in place of aluminum-lithium alloys. Zinc, magnesium, nickel and cadmium, and even mercury, can be used to make batteries in place of lithium. (It must be noted that mercury is being phased out of use due to the fact it is so poisonous.)
Further Reading
- Common Minerals and Their Uses, Mineral Information Institute.
- More than 170 Mineral Photographs, Mineral Information Institute.
|
Disclaimer: This article is taken wholly from, or contains information that was originally published by, the Mineral Information Institute. Topic editors and authors for the Encyclopedia of Earth may have edited its content or added new information. The use of information from the Mineral Information Institute should not be construed as support for or endorsement by that organization for any new information added by EoE personnel, or for any editing of the original content. |