The addition of iron (0.1 mol) caused the disappearance of Ɵ-Al2O3 phase and appearance of a new phase with a cubic structure, AlFe2O4 (Al+3Fe+2Fe+3O−24) (see Fig. 3). Further increase of iron (0.2 mol) resulted in the formation of a phase with hercynite structure, FeAl2O4 (Fe+2Al+32O−24). The FeAl2O4 is a normal spinel structure in which Al+3 cations are placed on one half of the octahedral sites and Fe+2 cations on one eighth of the octahedral sites [40,49]. The lattice parameters of FeAl2O4 shown in Table 2 are very close to the values reported by Dutta and Sharma for the iron and aluminium acetylacetonate complexes prepared by thermal annealing.