The effect of KI on the thermal decomposition of cobalt(III)-ammine complexes

Abstract Evolved gas analysis (EGA) was used to investigate the effect of KI on the thermal decomposition of five cobalt(III)-ammine complexes, [Co(NH 3 ) 5 N 3 ]Cl 2 , [Co(NH 3 ) 5 NO 2 ]Cl 2 , [Co(NH 3 ) 5 Cl]Cl 2 , [Co(NH 3 ) 4 CO 3 ]Cl and [Co(NH 3 ) 6 ]Cl 3 , in a hydrogen atmosphere. It was found that the presence of KI shifts the thermal decomposition of these complexes to a lower temperature, and decreases the activation energies of the deammination reactions. The electron transfer from I − to Co(III) is believed to play an important role in the decomposition process.