2925.     ---------------.  [RUFF, O., AND GERSTEN, E.]  [Carbides of Manganese and Nickel.]  Ber. deut. chem. Gesell., vol. 46, 1913, pp. 400-413; Chem. Abs., vol. 7, 1913, p. 1848.

        Molecular heats of formation of Mn₃C=-12.9±2.14, Fe₃C=-15.3±0.2 and Ni₃C=-394±10 cal.  The Ni₃C is very unstable and is not obtained in a pure condition.  Mn₃C is comparatively stable and is obtained by heating Mn in a C crucible with C at 1,600° in an electric vacuum furnace.  Ni₃C is formed at 2,100°.  The maximum amount of C found in the carbide is 6.42%.