Lithium

LITHIUM, a chemical element, symbol Li, atomic number 3, a silvery-white metal, atomic weight 6.940 (isotopes 6 and 7), melting point 186°C; belongs to the group of alkali metals and has the lowest specific gravity (0.59) compared to other metals. Discovered by Arfvedson in 1817 in the mineral petalite. It is found mainly in the form of silicate compounds in the minerals petalite, lepidolite, triphyline, amblygonite, and others; it is also found in some mineral waters (for example, in certain springs of Baden-Baden, Elster, and Cornwall). Traces of lithium compounds are quite widely distributed in the soil and are taken up by plants, especially tobacco and beet; in the ash of which this element can be detected spectroscopically. Lithium compounds impart a bright red color to the flame of a Bunsen burner. Metallic lithium, obtained by the electrolysis of fused lithium chloride, resembles sodium in its properties; lithium decomposes water, combines directly with oxygen (Li_sO), hydrogen (LiH), and nitrogen (Li₃N). The relatively greater insolubility of the hydrate of lithium oxide (LiOH), carbonate (Li₂C0₃), and phosphate (Li₃P0₄.2H₂0) distinguishes lithium from the corresponding compounds of other alkali metals and brings it closer to magnesium. The physiological action of various lithium compounds is very close to that of potassium salts. Upon the introduction of toxic doses into the blood, depression and paralysis of the central nervous system, muscles, and heart are observed. On the heart, lithium acts like potassium, only somewhat weaker than it (see Potassium). The gastrointestinal tract is irritated by lithium more strongly than by potassium, which is observed not only upon oral administration but also upon parenteral introduction; upon the administration of toxic doses, acute gastroenteritis develops. Lithium compounds are absorbed relatively quickly but excreted relatively slowly; the main excretion pathways are the kidneys and gastrointestinal tract; it is also excreted in milk. A diuretic effect of lithium compounds is noted (the mechanism of which is probably the same as that of potassium). Lipowitz in 1841 found that lithium carbonate dissolves uric acid four times better than sodium carbonate; a few years later lithium was introduced into medicine for the treatment of gout, relying on the dissolution of uric acid deposits (for example, gouty nodes), as well as for urinary stones and chronic rheumatism. A recent indication of the anticoagulant properties of lithium citrate (DeToni) has not yet found therapeutic application. Preparations. 1. Lithium bromatum (FUP), LiBr, lithium bromide, a white, easily crumbling crystalline powder on air, of a salty, slightly bitter taste; very easily soluble in water, easily soluble in alcohol. It is recommended for gout, neuroses, and hysteria; doses 0.1-0.3-0.5, several times a day in solutions; contains more bromine than potassium bromide (90% instead of 66%). It must be kept in well-closed glass vessels with paraffined stoppers. 2. Lithium carbonicum (F VII), Li₂C0₃, lithium carbonate; a light white powder; soluble in 83 parts of cold and 137 parts of boiling water; solutions have a weakly alkaline reaction. Doses 0.03-0.3, several times a day; given for gout, but without special success. 3. Lithium chloratum, LiCl, lithium chloride, a white powder, crumbling on air; well soluble in water, alcohol, and in a mixture of alcohol with ether; kept like the first preparation. Used for the preparation of artificial mineral waters. 4. Lithium acetylo-salicylicum, Hydropyrin, CH₃CO.O.C_eH₄COOLi, a white crystalline powder, attracting moisture and decomposing on air. Proposed as a substitute for aspirin in doses of 0.2-0.5, several times a day; the maximum single dose is 1.0; per day 5.0. 5. Lithium benzoicum, C_eH₅COOLi + H₂0; lithium benzoate, a white powder; does not decompose on air; soluble in 3 parts of cold water and 2 parts of boiling water; doses 0.1-0.3, three or four times a day. 6. Lithium citricum, CVHgO^Lia +4H _aO; a white crystalline powder, crumbling on air, soluble in water and alcohol; kept in well-closed vessels with paraffined stoppers. Application and doses as for lithium carbonate. 7. Lithium jodatum, LiJ, lithium iodide, a white powder, yellowing and crumbling on air, of a bitter-salty taste; easily soluble in water; kept like the previous preparations. Doses 0.2-0.4, several times a day in solutions for gout. 8. Lithium salicylicum C₇H_s0₃ Li; a white or reddish powder of a sweet taste, easily soluble in water and alcohol; recommended for completing the course of treatment with sodium salicylate in gout and various forms of subacute and chronic rheumatism. Doses of 0.5, three or four times a day. 9. Urosin C₆H₇ (OH)₄COOLi; lithium citrate, very hygroscopic crystals. Sold as a 50% solution, syrup-like, slightly sour to the taste; doses per day 6-10 g; also in tablets containing 50% Urosin and 50% sugar; per day 6-10 tablets. Recommended for gout. 10. Uresin, (Russian preparation) a mixture of lithium citrate and citrate of urotropin; a white crystalline powder, easily soluble in water; given in decigrams.