2908.     ROTH, W. A.  [Thermochemistry of Iron, Manganese, and Nickel.]  Ztschr. angew. Chem., vol. 42, 1929, pp. 981-984; Arch. Eisenhüttenw., vol. 3, 1929, pp. 339-346; Chem. Abs., vol. 24, 1930, p. 291.

        Heats of formation were determined with a calorimetric bomb, paraffin being used to start the reactions.  The reaction products were carefully analyzed.  Values found (in general slightly higher than those previously accepted) are given in calories:  MnO 96.2; Mn₃O₄, 343.8; MnCO₃, 218.2; MnO+CO₂, 27.7; Mn₃C, 23; FeO, 64.0; Fe₃O₄, 265.7; Fe₂O₃, 197.6; FeCO₃, 171.7; FeO+CO₂, 13.4; Fe₃C, -5.4; Fe(CO)₅, 54.4; NiO, 58.6; Ni₃C, -9.2, all at constant volume.  Values at constant pressure, also given, are similar but not identical.