Mass spectrometric study of the thermal decomposition of dimanganese decacarbonyl and dicobalt octacarbonyl

Abstract

The free radicals •Mn(CO) 5 and •Co(CO) 4 have been produced by the pyrolysis of Mn 2 (CO) 10 and Co 2 (CO) 8 in graphite flow reactors. The effusing molecular beams from these reactors were analyzed mass spectrometrically. Evidence is presented for the following equilibria[Formula: see text]From the temperature dependence of the equilibrium constants, enthalpy changes of 24.9 ± 2 and 14.5 ± 2 kcal/mole, respectively, have been obtained. These enthalpy changes give D(Mn—Mn) = 21 ± 3 kcal/mole and D(Co—Co) = 13 ± 3 kcal/mole, which substantiate the earlier literature values based on electron impact measurements.