Synthesis of lithium ferrites from polymetallic carboxylates

Abstract

Lithium ferrite was prepared by the thermal decomposition of three polynuclear complex compounds containing as ligands the anions of malic, tartaric and gluconic acid: (NH4)2[Fe2.5Li 0.5(C4H4O5)3(OH) 4(H2O)2]·,4H2O (I), (NH 4)6[Fe2.5Li0.5(C4H 4O6)3(OH)8]·,2H2O (II) and (NH4)2[Fe2.5Li0.5(C 6H11O7)3(OH)7] (III). The polynuclear complex precursors were characterized by chemical analysis, IR and UV-Vis spectra, magnetic measurements and thermal analysis. The obtained lithium ferrites were characterized by XRD, scanning electron microscopy, IR spectra and magnetic measurements. The single α-Li0.5Fe 2.5O4 phase was obtained by thermal decomposition of the tartarate complex annealed at 700 °C for 1 h. The magnetization value ≈ 50 emu g-1 is lower than that obtained for the bulk lithium ferrite due to the nanostructural character of the ferrite. The particle size was smaller than 100 nm.