Physico-chemical studies on the thermolysis of strontium and barium ferrimaleates

The thermolysis of strontium and barium tris(maleato)ferrates(III), M-3[Fe( C2H2C2O4)(3)](2). xH(2)O has been investigated from ambient temperature to 800 degreesC using simultaneous TG-DTG-DTA, XRD, Mossbauer and IR spectrosc opic techniques. After dehydration the anhydrous complexes undergo decompos ition to yield an iron(II)maleate/oxalate intermediate in the temperature r ange of 240-280 degreesC. An oxidative decomposition of iron(II) species le ads to the formation of alpha -Fe2O3, and respective alkaline earth metal c arbonate in the successive stages. Finally at 540-590 degreesC, a solid sta re reaction occurs between alpha -Fe2O3 and strontium/barium carbonate resu lting in the formation of SrFeO2.5 and BaFe2O4, respectively.