Moessbauer study of the thermal decomposition of alkali dihydroxo tetrapropionato ferrates(III)

Thermal decomposition of alkali dihydroxo tetrapropionato ferrates(III), M3[Fe(C2H5COO)4(OH)2]xH2O (M=Li, Na, K) has been studied upto 973 K. The complexes were calcined isothermally at various temperatures i.e., 473, 573, 773 and 973 K. The intermediates/products have been characterized by Moessbauer, infrared spectroscopies and XRD powder diffraction. The anhydrous complexes directly decompose to give α-Fe2O3 and alkali metal carbonate without undergoing reduction to iron(II) moiety. An increase in the particle size and internal magnetic field of α-Fe2O3 has been observed with increasing decomposition temperature. At higher temperature (973 K) MFeO2 is formed as the final thermolysis product due to a solid state reaction between α-Fe2O3 and alkali metal carbonate. (author)