833.    EMMETT, P. H., AND SCHULTZ, J. F.  Equilibrium in the System:  Carbon Monoxide-Water-Cobalt Oxide-Hydrogen.  Free-Energy Changes for the Reaction CoO+H2=Co+H2O and the Reaction Co+1/2 O2=CoO.  Jour. Am. Chem. Soc., vol. 51, 1929, pp. 3249-3262; Chem. Abs., vol. 24, 1930, p. 774.

      The object was to determine at several temperatures the equilibrium ratio of H2O:H2 in the presence of Co.  CoO, reduced by H2 at the temperature desired, was subjected to various mixtures of H2+H2O, and the effluent gases were analyzed for H2 and H2O.  A second catalyst was prepared by reducing Co3O4 to CoO.  Equilibrium was approached at each temperature from both the H2O sides.  A modification of the flow system of Pease and Cook, was used.  The ratio H2O:H2 at 335 was 855; at 450, 671; at 515, 57.00.3; and at 570, 50.50.2.  ∆F298 for the reaction CoO+H2=H2O+Co was calculated as 3,678 calories.  ∆H298 was calculated as 1,646 calories, as compared with 300 calories calculated from the heats of formation of CoO and H2O.  X-ray photographs indicated that at 500 H2O did not form Co3O4 from CoO. ∆F1373 for the formation of CoO from Co and O2 was calculated at 32,050 calories, and from this, partial pressures of O2 in equilibrium with CoO and Co at 1,100 was calculated as 0.5X10-7 mm.  Transformation of hexagonal to cubic Co takes place at 340-360.