355a.     BRIMM, E. O. AND LYNCH, M. A.  Estimated Bond Order in Metal Carbonyls.  Am. Chem. Soc., 121st Meeting Abs., March-April, 1952, p. 38-N.

        The presence of partial double bond character of the metal-C bond in metal carbonyls has been postulated to account for the shortness of the observed bond lengths.  The % double bond character of the metal-C bonds in metal carbonyls, substituted metal carbonyls, and hydrocarbonyls is estimated by means of Pauling’s principle of electroneutrality.  A decrease in the order of the C-O bond would result from this partial double bond formation.  Changes in the characteristic infrared absorption of the C-O bond are correlated with the estimated bond orders.  Evidence is presented for the presence of bridging CO in dicobalt octacarbonyl and tetracobalt dodecacarbonyl and their absence in dimanganese decacarbonyl and dirhenium decacarbonyl.