Physico-chemical Studies on Thermal Decomposition of Alkali Tris(maleato)ferrates(III)

Abstract

The thermal decomposition of alkali tris(maleato)ferrates(III), M3 [Fe(C2 H2 C2 O4 )3 ] (M =Li, Na, K) has been studied isothermally and non-isothermally employing simultaneous TG-DTG-DTA, XRD, Mossbauer and IR spectroscopic techniques. The anhydrous complexes decompose in the temperature range 215–300°C to yield Fe(II)maleate as an intermediate followed by demixing of the cations forming α-Fe2 O3 and alkali metal maleate/oxalate in successive stages. In the final stage of remixing of the cations (430–550°C) a solid state reaction occurs between α-Fe2 O3 and alkali metal carbonate leading to the formation of fine particles of respective ferrites. The thermal stabilities of the complexes have been compared with that of alkali tris(oxalato)ferrates(III).