Title: Lithium
CAS Registry Number: 7439-93-2
Literature References: Li; at. wt 6.941; at. no. 3; valence 1. Group IA (1). Alkali metal. Occurrence in earth's crust: 20 ppm. Naturally occurring isotopes: 7 (92.5%); 6 (7.5%); artificial radioactive isotopes: 5, 8-11; all are unstable (T½ < 1 sec). Discovered as salt in 1817 by Arfvedson: Ann. Chim. Phys. [2] 10, 82 (1819); metal prepared independently by Davy and Brandé in 1818. Occurs in a number of minerals: spodumene (LiAlS2O6), lepidolite [K(Li,Al)3(Si,Al)4O10(F,OH)2], petalite (LiAlSi4O10), amblygonite (AlPO4,LiF), and triphylite (LiFePO4). Also recovered from natural brines. Prepn of the metal by electrochemical processes: Guntz, Compt. Rend. 117, 732 (1893); Ruff, Johannsen, Z. Elektrochem. 12, 186 (1906); by reduction of the oxide with magnesium or aluminum: Warren, Chem. News 74, 6 (1896); Hanson, US 2028390 (1936). Reviews of biology, pharmacology and toxicity of lithium ion: Schou, "Lithium in Psychiatry: A Review" in Psychopharmacology, A Review of Progress 1957-1967, D. H. Efron, Ed. (Public Health Service Publication No. 1836, 1968) pp 701-718; Doig et al., J. Chem. Educ. 50, 343-345 (1973); Samuel, Gottesfeld, Endeavour 32, 122-128 (1973); Saran, Gaind, Clin. Toxicol. 6, 257-269 (1973); Schou, Annu. Rev. Pharmacol. Toxicol. 16, 231-243 (1976). Reviews: Hart, Beumel, "Lithium and its Compounds" in Comprehensive Inorganic Chemistry vol. 1, J. C. Bailar, Jr. et al., Eds. (Pergamon Press, Oxford, 1973) pp 331-367; C. W. Kamienski et al. in Kirk-Othmer Encyclopedia of Chemical Technology vol. 15 (Wiley-Interscience, New York, 4th ed., 1995) pp 434-463; Chemistry of the Elements N. N. Greenwood, A. Earnshaw, Eds. (Pergamon Press, New York, 1984) pp 75-116; Patty's Industrial Hygiene and Toxicology vol. 2C, G. D. Clayton, F. E. Clayton, Eds. (John Wiley & Sons, Inc., New York, 4th ed., 1994) pp 2087-2097. Review of pharmacology: N. J. Birch, J. D. Phillips, Adv. Inorg. Chem. 36, 49-75 (1991); and clinical use: L. H. Price, G. R. Heninger, N. Engl. J. Med. 331, 591-598 (1994).
Properties: Silvery-white metal; body-centered cubic structure; becomes yellowish on exposure to moist air. mp 180.54°. bp 1347°. Also reported as bp 1336 ± 5°: Hartman, Schneider, Z. Anorg. Chem. 180, 275 (1929). d20 0.534. Hardest of the alkali metals; Mohs' hardness 0.6. Heat capacity at constant pressure (25°): 5.892 cal/mole deg. See: Douglass et al., J. Am. Chem. Soc. 77, 2144 (1955). E° (aqueous) Li/Li+ 3.045 V. Reacts with H2O forming the hydroxide and H2. Reacts violently with inorganic acids; reacts slowly with cold H2SO4. Sol in liq ammonia forming a blue soln. Does not react with oxygen at room temp; forms Li2O when heated to 100° or higher. Emits characteristic crimson color (670.8 nm) in flame. Flammable. Keep under mineral oil or other liquid free from oxygen or water. Li metal ignites in air near its mp; presents fire and explosion risk when exposed to water, N, acids or oxidizing reagents.
Melting point: mp 180.54°
Boiling point: bp 1347°; bp 1336 ± 5°: Hartman, Schneider, Z. Anorg. Chem. 180, 275 (1929)
Density: d20 0.534
CAUTION: Potential symptoms of mild overexposure to the Li ion by ingestion of lithium salts are impaired concentration, lethargy, irritability, muscle weakness; moderate overexposure may cause disorientation, confusion, drowsiness; severe overexposure may cause impaired consciousness with progression to coma, convulsions, and impaired renal function (Price, Heninger). Direct contact with metal may be corrosive and cause skin and eye burns. See: Fire Protection Guide to Hazardous Materials (National Fire Protection Assoc., Quincy, MA, 12th ed., 1997) Section 49, p 82. See also: Clinical Toxicology of Commercial Products, R. E. Gosselin et al., Eds. (Williams & Wilkins, Baltimore, 5th ed., 1984) Section III, pp 241-245.
Use: In prodn of organometallic alkyl and aryl lithium compounds; in prodn of high-strength, low-density aluminum alloys for the aircraft industry; extremely tough, low-density alloys with aluminum and magnesium used for armour plate and aerospace components. In polymerization catalysts for the polyolefin plastics industry; manuf of high-strength glass and glass-ceramics. As anode in electrochemical cells and batteries; as chemical intermediate in organic syntheses. Lithium stearate as thickener and gelling agent to transform oils into lubricating greases. |