Moessbauer studies of thermal decomposition of hexaamminecobalt(III) hexacyanoferrate(III) and hexaamminecobalt(III) hexachloroferrate(III) in air and in nitrogen atmosphere

Thermal decomposition of hexaamminecobalt(III) hexacyanoferrate(III) (1) and hexaamminecobalt(III) hexachloroferrate(III) (2) in air as well as in nitrogen atmosphere was studied by using Moessbauer spectroscopy, TGA, DTA, IR spectroscopy, and magnetic susceptibility measurement. 1, when heated in air, is stable up to 200 0C and then converted into hexacyanoferrate(II) and finally to ferrites; in inert atmosphere iron metal and carbides are formed above 4000C. 2 in air is reduced to iron(II) species and finally to ferrites; in inert atmosphere ligand exchange takes place forming cobalt(II) chloride. A mechanism is proposed for the decompositions of 1 and 2. (author)