262a.    BLANCHARD, A. A., and GILMONT, P.  Preparation of Cobalt Carbonyl, Cobalt Nitrosyl Carbonyl and Cobalt Carbonyl Hydride by the Cyanide Method.  Jour. Am. Chem. Soc., vol. 62, 1940, pp. 1192-1193; Chem. Abs., vol. 34, 1940, p. 4,354.

                   An alkaline suspension of a Co salt absorbs CO almost quantitatively to form KCo (CO)₄, but only in the presence of a carrier such as a small amount of a cyanide.  Treatment of KCo(CO)₄ with NO gives Co(NO)(CO)₃.  The addition of an excess of HCl to the reaction mixtures gives the volatile HCo(CO)₄, which condenses at –79° to a solid; it melts at –33° and decomposes above that temperature into (Co(CO)₄)₂ and H₂.