762.    EASTMAN, E. D.  Equilibria in the Systems; Fe-C-O and Fe-H-O, and the Free Energies of the Oxides of Iron.  Jour. Am. Chem. Soc., vol. 44, 1922, pp. 975-998; Chem. Abs., vol. 16, 1922, p. 1901.

     Summary of the widely scattered and often discordant data relating to the oxides of Fe and to the equilibria in which they are involved, with an attempt to appraise and interpret the results.  For each of the reactions:  3FeO+CO₂=Fe₃O₄+CO, Fe+CO₂=FeO+CO, and 3Fe+4CO₂=Fe₃O₄+4CO the equilibria constant (CO₂) : (CO) has been plotted for different temperatures.  The lines for the 3 reactions meet in the invariant point, where there are 3 solid phases and a gas phase (theoretically the C occurs only in the gas phase) at about 560° and (CO₂) : (CO) = 1.  Similarly for the reactions:  FeO+H₂=Fe+H₂O, Fe₃O₄+H₂=3FeO+H₂O, and Fe₃O₄+4H₂=Fe+4H₂O the lines meet at about 560° and where (H₂) : (H₂O) = 4.  The free energies of the oxides of Fe have been calculated by means of the relation ∆F = -RTlnK.