EMISSION MOSSBAUER STUDIES ON COBALT CARBONYL-COMPLEXES LABELED WITH CO-57

Three different Co-57-doped cobalt carbonyl complexes, NaCo (CO)4, Co2 (CO)8, and CH3C(=O)Co(CO)3PPh3, representing a formal valence state of cobalt -1, 0, and +1, respectively, were prepared and studied by emis sion Mossbauer spectroscopy. As a result of aftereffects of the EC dec ay of Co-57, Fe2+ and Fe3+ states could be identified in the Mossbauer spectra with hardly any dependence on the initial valence state of co balt. This observation is explained by assuming the fragmentation of t hese molecules as result of the electron loss caused by the Auger ioni zation of the nucleogenic Fe-57 atom.