LITHGOW, a town of Cook county, New South Wales, Australia, 96 m. W.N.W. of Sydney by rail. Pop. (1901) 5268. The town is situated at an altitude of 3000 ft., in a valley of the Blue Mountains. It has pottery and terra-cotta works, breweries, a tweed factory, iron-works, saw-mills, soap-works and brickfields. Coal, kerosene shale, iron ore and building stone are found in the district.
LITHIUM [symbol Li, atomic weight 7.00 (O = 16)], an alkali metal, discovered in 1817 by J. A. Arfvedson (_Ann. chim. phys._ 10, p. 82). It is only found in combination, and is a constituent of the minerals petalite, triphyline, spodumene and lepidolite or lithia mica. It occurs in small quantities in sea, river and spring water, and is also widely but very sparingly distributed throughout the vegetable kingdom. It may be obtained (in the form of its chloride) by fusing lepidolite with a mixture of barium carbonate and sulphate, and potassium sulphate (L. Troost, _Comptes rendus_, 1856, 43, p. 921). The fused 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 solution evaporated and the lithium chloride extracted by a mixture of dry alcohol and ether. The metal may be obtained by heating dry lithium hydroxide with magnesium (H. N. Warren, _Chem. News_, 1896, 74, p. 6). L. Kahlenberg (_Jour. phys. Chem_., 3, p. 601) obtained it by electrolysing the chloride in pyridine solution, a carbon anode and an iron or platinum cathode being used. O. Ruff and O. Johannsen (_Zeit. elektrochem._, 1906, 55, p. 537) electrolyse a mixture of bromide and chloride which melts at 520°. It is a soft, silvery-white metal, which readily tarnishes on exposure. Its specific gravity is 0.59, and it melts at 180° C. It burns on ignition in air, and when strongly heated in an atmosphere of nitrogen it forms lithium nitride, Li3N. It decomposes water at ordinary temperature, liberating hydrogen and forming lithium hydroxide.
_Lithium hydride_, LiH, obtained by heating the metal in a current of hydrogen at a red heat, or by heating the metal with ethylene to 700° C. (M. Guntz, _Comptes rendus_, 1896, 122, p. 244; 123, p. 1273), is a white solid which inflames when heated in chlorine. With alcohol it forms lithium ethylate, LiOC2H5, with liberation of hydrogen. _Lithium oxide_, Li2O, is obtained by burning the metal in oxygen, or by ignition of the nitrate. It is a white powder which readily dissolves in water to form the _hydroxide_, LiOH, which is also obtained by boiling the carbonate with milk of lime. It forms a white caustic mass, resembling sodium hydroxide in appearance. It absorbs carbon dioxide, but is not deliquescent. _Lithium chloride_ LiCl, prepared by heating the metal in chlorine, or by dissolving the oxide or carbonate in hydrochloric 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 salt in the presence of sodium hydroxide, is almost insoluble in water. _Lithium ammonium_, LiNH3, is obtained by passing ammonia gas over lithium, the product being heated to 70° C. in order to expel any excess of ammonia. It turns brown-red on exposure to air, and is inflammable. It is decomposed by water evolving hydrogen, and when heated _in vacuo_ at 50°-60° C. it gives lithium and ammonia. With ammonia solution it gives hydrogen and _lithiamide_, LiNH2 (H. Moissan, _ibid._, 1898, 127, p. 685). _Lithium carbide_, Li2C2, obtained by heating lithium carbonate and carbon in the electric furnace, forms a transparent crystalline mass of specific gravity 1.65, and is readily decomposed by cold water giving acetylene (H. Moissan, _ibid._, 1896, 122, p. 362).