356.     BRINER, E., AND SENGLET, R.  [Experiments on the Carbides of Aluminum, Nickel, and Copper.]  Jour. chim. phys., vol. 13, 1915, pp. 351-375; Chem. Abs., vol. 10, 1916, p. 3041.

       On being heated Al₄C₃ dissociates into its elements, which in the presence of air are immediately oxidized.  The reaction was studied at 540°, but the decomposition is appreciable at lower temperatures.  In the synthesis of the substance, powdered Al was heated with sugar C for 2-hr. periods and the residue tested for presence of carbide by the addition of HCl to produce CH₄.  At 550° no appreciable quantity was formed, but at 750° and 900°, respectively, small yields were obtained, providing the reaction of Al₄C₃=4Al+3C to be reversible.  Attempts to measure the speed of the reaction were unsuccessful.  Ni₃C is formed according to the equation 3Ni+C=Ni₃C at temperatures about 2,100°; at lower temperatures it dissociates into its constituents, rapidly at 1,600° and relatively slowly at 900°.  At the relatively low temperatures, while the interacting substances are in the solid state, the reaction is endothermic; at the higher temperatures, when the Ni and C are gaseous and in the atomic state, it becomes exothermic.  Studies of the formation of carbides of Cu indicate that an endothermic carbide is formed at high temperatures that decomposes at 1,600°, but further confirmatory work is needed.