Silver bromide monoxide

A variety of cobalt carbonyl derivatives have been obtained in which the cobalt atom is o-bonded to an element other than carbon. These have been obtained both by wet methods involving metathesis of a solution of [Co(CO)4] with an appropriate derivative of the element to be bonded to cobalt and by dry methods involving high-pressure reactions of carbon monoxide with a mixture of cobalt metal or one of its compounds and an appropriate derivative of the other element. Thus, treatment of aqueous solutions of [Co(CO)4] with silver nitrate or mercury(II) cyanide gave the derivatives AgCo(CO)4 or Hg[Co(CO)4], respectively (220). The mercury derivative can also be prepared by the dry method, involving treatment of a mixture of mercury(II) bromide and cobalt metal with 200 atm of carbon monoxide at 150° C (247). The silver derivative AgCo(CO)4 could not be prepared by the dry method (247). The yellow zinc and cadmium derivatives M[Co(CO)4]2 (M = Zn or Cd) can be obtained by treatment of cobalt(II) bromide, cobalt metal, or dicobalt octacarbonyl with zinc or cadmium metal in the presence of carbon monoxide under pressure (247). 

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