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.