LITHIUM (Neo-Lat., from (O:. Wes, stone). A metallic chemical clement, whose oxide was discovered in 1817 by Arfvedson. The metal itself was first obtained by Itrande in 1822, and a quarter of a century later Bunsen and Mat thiessen invented the process 110W used in mak ing it (see below), Lithium is distributed in na ture widely, but in very -mall quantities, the only minerals containing considerable amounts of it being the rare minerals spodumene, petante, and lepidolite. It is also found in certain min eral waters, and in the leaves of certain plants. Finally, it occurs in meteorites, and its presence has been detected in the sun. Lithium com pounds being used in medicine, the sources of the element, especially lepidolite, arc exploited on a considerable commercial scale. The mineral is first fused, so as to render it capable of being decomposed by strong hydrochloric acid: the latter is then caused to act on the mineral for several hours, nitric acid is added to the result ing solution, then the solution is diluted and neutralized with sodium carbonate, 1% hich pre cipitates out the iron, aluminum, magnesium, etc. ( hi filtering, the liquid is evaporated to a small bulk ;Id mixed with a strong solution of sodium carbonate, which now causes the precipitation of lithium carbonate. This carbonate may then be transformed into other lithium compounds, among which the chloride may be used to obtain metallic lithium, by means of a strong voltaic current passed through the fused salt.
The element lithium (symhol Li: atomic weight. 7.03) is the lightest metal known, its spe gravity being about 0.59. It is white, it can be pressed into wire, and it can be welded at Ordinary temperatures. If exposed to the air. it soon becomes covered with a yellowish white film of oxide. Like sodium and potassium, with which it is classed as one of the 'alkali metals,' it decomposes water with great readiness, it is., on the other hand. less volatile than sodium
or potassium. and does not distil at a red heat. Its melting-point is ISO' C. (31I5° 1,rrilit' al Con Among these deserve mention the oxide. the carbonate. the citrate, and the salicylate. The oxide, Li C), may he prepared by heating the ea•bonate with iliarcoal: with water it forms the hydroxide. Li011, whieli may. by crystallization from aqueous aleohol. be obtained as LiOH 11.,0: the hydroxide may also be prepared by the action of lime on lithium ear. borate. The carbonate of lithium. 1.i,C11. is a light. 'white powder sparingly soluble in water, lint insoluble in alcohol. The citrate of lithium. Lic„11„0.,, is a white powder readily soluble hi water: it may be prepared by the action of citric acid on lithium ca•honate: 'effervescent lithium citrate' be prepared by mixing sugar with citric acid. drying the mixture and adding to' it sufficient quantities of sodium bicarbonate and lithium carbonate. The solicylate of lithium, LiC,11,0, is a white powder readily soluble in water and in alcohol; it may be prepared by heat ing lithium carbonate with salicylic acid and water, until effervescence ceases. A number of lithium salts are used in gout, in uric acid grim], and calculus, owing to their capacity for causing sodium orate to dissolve in water. The carbon ate, in the form of a lotion, is used to alleviate the pain of gouty inflammation and to heal gouty ulcers. The presence of lithium compounds in a given substance can be readily recognized by in troducing a small amount of the substance into a colorless flame (like that of the Bunsen burn er), to which they impart a characteristic red coloration.