Chemical elements
  Lithium
    Isotopes
    Energy
    Production
    Application
    Physical Properties
    Chemical Properties
      Lithium hydride
      Lithium chloride
      Lithium bromide
      Lithium iodide
      Lithium iodide tetrachloride
      Lithium hypochlorite
      Lithium chlorate
      Lithium perchlorate
      Lithium bromate
      Lithium iodate
      Lithium periodates
      Lithium monoxide
      Lithium peroxide
      Lithium hydroxide
      Lithium monosulphide
      Lithium polysulphides
      Lithium sulphite
      Lithium sulphate
      Lithium persulphate
      Lithium thiosulphate
      Lithium dithionate
      Lithium selenide
      Lithium selenite
      Lithium selenate
      Lithium chromate
      Lithium permanganate
      Lithium molybdates
      Lithium nitride
      Lithium hydrazoate
      Lithamide
      Lithium nitrite
      Lithium nitrate
      Lithium phosphide
      Lithium orthophosphate
      Lithium pyrophosphate
      Lithium metaphosphate
      Lithium arsenide
      Lithium meta-arsenite
      Lithium arsenate
      Lithium antimonide
      Lithium antimonate
      Lithium carbide
      Lithium carbonate
      Lithium percarbonate
      Lithium cyanide
      Lithium thiocyanate
      Lithium silicide
      Lithium silicates
      Lithium borates

Lithium carbide, Li2C2






The Lithium carbide, Li2C2 was first prepared by Moissan by the reduction of lithium carbonate with charcoal in the electric furnace -

Li2CO3+4C=Li2C2+3CO.

Tucker and Moody were unable to prepare the almost pure carbide described by Moissan, and attributed their failure to the very small temperature-interval between the formation and the decomposition of the substance. The carbide is also formed by the interaction of lithium and any of the allotropic modifications of carbon in vacuum at dull red heat; and by the combination of the metal with carbon monoxide or dioxide, or with ethylene or acetylene, an impure product is obtained.

Lithium carbide is a white or grey crystalline substance, its density at 18° C. being 1.65. At bright red heat it is decomposed, and Tucker and Moody found that at 925° C. and a pressure of fifty pounds to the square inch it absorbs nitrogen freely with formation of cyanamide, dicyanamide, and cyanide. It is a powerful reducer, decomposing water energetically at ordinary temperatures with formation of acetylene -

C2Li2+2H2O = C2H2+2LiOH.

It ignites in fluorine and chlorine without the application of heat, and on gentle warming in the vapour of bromine, iodine, or phosphorus. It combines with oxygen, sulphur, and selenium at dull redness.

Guntz gives the heat evolved in its action on water as 37.1 Cal., and calculates the heat of formation of the carbide from its elements to be that given by the equation

2[C](diamond)+2[Li]=[Li2C2] + 11.3 Cal.

Moissan has prepared an ammonia addition-product of primary lithium acetylide, LiHC2, although the free primary compound has not been isolated.


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