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Literature Abstracts

 1440.    HOFER, L. J. E., AND PEEBLES, W. C.  Preparation and X-Ray Diffraction Studies of a New Cobalt Carbide.  Jour. Am. Chem. Soc., vol. 69, 1947, pp. 893-899; Chem. Abs., vol. 41, 1947, p. 4363.

       CO reacts with finely divided Co at 226°-230° to form a product of the composition corresponding to the formula Co₂C (9.3% C).  This product reacts completely with H₂ at 240°-250° to give Co metal and CH₄.  The carburization of Co at temperatures higher than 230° leads to C contents higher than 9.3%.  However, only C up to 9.3% reacts with H₂ at 240°-250° to form CH₄.  Carbon in excess of this amount reacts with H₂ only at temperatures above 350°.   The paper reports the results of studies on the carburization of Co by CO at various temperatures, and the reaction of H₂ with, and X-ray analyses of, the resulting products.  The results indicate that the easily hydrogenated C produced by the action of CO on finely divided Co metal is combined with Co to form a new crystalline species, Co₂C, whose structure is distinct from either a- or β-Co.  X-ray diffraction data indicate that the difficulty hydrogenated C is in the form of finely divided C crystallites.  Lattice parameter measurements of a-Co give no evidence of any solid solution of C in a-Co in a partly carburized sample.