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LITHIUM [symbol Li, atomic weight 7•o...

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Originally appearing in Volume V16, Page 785 of the 1911 Encyclopedia Britannica.
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LITHIUM [See also:symbol Li, atomic See also:weight 7•oo (0=16)] , an See also:alkali See also:metal, discovered in 1817 by J. A. Arfvedson (See also:Ann. chim. phys. TO, p. 82). It is only found in See also:combination, and is a constituent of the minerals See also:petalite, triphyline, See also:spodumene and See also:lepidolite or lithia See also:mica. It occurs in small quantities in See also:sea, See also:river and See also:spring See also:water, and is also widely but very sparingly distributed throughout the See also:vegetable See also:kingdom. It may be obtained (in the See also:form of its chloride) by fusing lepidolite with a mixture of See also:barium carbonate and sulphate, and See also:potassium sulphate (L. Troost, Comptes rendus, 1856, 43, p. 921). The fused See also:mass separates into two layers, the upper of which contains a mixture of potassium and lithium sulphates; this is lixiviated with water and converted into the mixed chlorides by adding barium chloride, the See also:solution evaporated and the lithium chloride extracted by a mixture of dry See also:alcohol and See also:ether. The metal may be obtained by See also:heating dry lithium hydroxide with See also:magnesium (H.

N. See also:

Warren, Chem. See also:News, 1896, 74, p. 6). L. Kahlenberg (Jour. phys. Chem., 3, p. 6or) obtained it by electrolysing the chloride in See also:pyridine solution, a See also:carbon anode and an See also:iron or See also:platinum See also:cathode being used. O. See also:Ruff and O. Johannsen (Zeit. elektrochem., 1906, 55, p. 537) electrolyse a mixture of bromide and chloride which melts at 5200.

It is a soft, silvery- ' See also:

Mommsen in C.I.L. x. 343 does not accept this statement, but an inscription found in 1885 confirms it.See also:white metal, which readily tarnishes on exposure. Its specific gravity is 0-59, and it melts at 18o° C. It See also:burns on ignition in See also:air, and when strongly heated in an See also:atmosphere of See also:nitrogen it forms lithium nitride, Li3N. It decomposes water at See also:ordinary temperature, liberating See also:hydrogen and forming lithium hydroxide. Lithium hydride, LiH, obtained by heating the metal in a current of hydrogen at a red See also:heat, or by heating the metal with See also:ethylene to 700° C. (M. Guntz, Comptes rendus, 1896, 122, p. 244; 123, p. 1273). is a white solid which inflames when heated in See also:chlorine. With alcohol it forms lithium ethylate, LiOC2H,, with liberation of hydrogen. Lithium See also:oxide, Li2O, is obtained by burning the metal in See also:oxygen, or by ignition of the nitrate.

It is a white See also:

powder which readily dissolves in water to form the hydroxide, LiOH, which is also obtained by boiling the carbonate with See also:milk of See also:lime. It forms a white See also:caustic mass, resembling See also:sodium hydroxide in See also:appearance. It absorbs carbon dioxide, but is not deliquescent. Lithium chloride LiCI, prepared by heating the metal in chlorine, or by dissolving the oxide or carbonate in hydrochloric See also:acid, is exceedingly deliquescent, melts below a red heat, and is very soluble in alcohol. Lithium carbonate, Li2CO3, obtained as a white amorphous precipitate by adding sodium carbonate to a solution of lithium chloride, is sparingly soluble in water. Lithium phosphate, Li3PO4, obtained by the addition of sodium phosphate to a soluble lithium See also:salt in the presence of sodium hydroxide, is almost insoluble in water. Lithium ammonium, LiNH3, is obtained by passing See also:ammonia See also:gas over lithium, the product being heated to 7o° C. in See also:order to expel any excess of ammonia. It turns See also:brown-red on exposure to air, and is inflammable. It is decomposed by water evolving hydrogen, and when heated in vacuo at 50°-6o° C. it gives lithium and ammonia. With ammonia solution it gives hydrogen and lithiamide, LiNH2 (H.. See also:Moissan, ibid., 1898, 127, p. 685).

Lithium See also:

carbide, Li2C2, obtained by heating lithium carbonate and carbon in the electric See also:furnace, forms a transparent crystalline mass of specific gravity 1.65, and is readily decomposed by See also:cold water giving See also:acetylene (H. Moissan, ibid., 1896, 122, p. 362). Lithium is detected by the faint yellow See also:line of See also:wave-length 6104, and the See also:bright red line of wave-length 6708, shown in its See also:flame spectrum. It may be distinguished from sodium and potassium by the sparing solubility of its carbonate and phosphate. The atomic weight of lithium was determined by J. S. See also:Stas from the See also:analysis of the chloride, and also by See also:conversion of the chloride into the nitrate, the value obtained being 7.03 (0 =16). The preparations of lithium used in See also:medicine are: Lithii Carbonis, dose 2 to 5 grs. ; Lithii Citras, dose 5 to 10 grs. ; and Lithii Citras effervescens, a mixture of citric acid, lithium citrate, tartaric acid and sodium bicarbonate, dose 6o to 120 grs. Lithium salts render the urine alkaline and are in virtue of their See also:action diuretic.

They are much prescribed for acute or chronic See also:

gout, and as a solvent to uric acid calculi or See also:gravel, but their action as a solvent of uric acid has been certainly overrated, as it has been shown that the addition of medicinal doses of lithium to the See also:blood serum does not increase the solubility of uric acid in it. In concentrated or large doses lithium salts cause vomiting and See also:diarrhoea, due to a gastro-See also:enteritis set up by their action. In medicinal use they should therefore be always freely diluted.

End of Article: LITHIUM [symbol Li, atomic weight 7•oo (0=16)]

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