Freeze-Dried Acetates Of Strontium And Iron As Reactive Precursors For Complexes Sr-Fe Oxides

The thermal decomposition of reactive freeze-dried acetate precursors for Sr-Fe-oxides was investigated by means of DTA, TG, mass spectroscopy and X-ray powder diffractometry. In the case of decomposition of Fe(III)-mu-oxo-acetate four superimposed main steps are characterized as release of (a) H2O, (b) acetic acid and ketene (c) methane, ketene and CO2 and (d) acetone and CO2. On careful decomposition, single phase gamma-Fe2O3 can be formed. The decomposition of freeze-dried mixed Fe-Sr-acetates reflects some aspects of the single acetates, but also an interaction between the components. The interactions result in a lower decomposition temperature of Sr-acetate (release of acetone and formation of SrCO3). The decomposition temperature of SrCO3 in the reactive mixture is also lowered. The simultaneous decomposition of SrCO3 and its reaction with the Fe-component results directly in the formation of the expected complex Sr-Fe-oxide.