Formation of oxidized molybdenum-bearing ferrites, Fe2.95 –xMoxO4(x = 0.03–0.30) in aqueous suspensions by air oxidation, and valence state of molybdenum

Oxidized molybdenum-bearing ferrites (MO : Fetot. mol ratios 0.012–0.114 : 1) have been formed by air oxidation of iron hydroxide suspensions, which were prepared in the presence of molybdenum(VI) ions at initial MO: Fetot. mol ratios of 0.015–0.300 : 1, at pH 9.0, and 65°C. The molybdenum content in the centre part of the ferrite particles was found to be very low. X-Ray photoelectron spectra of the MO 3d5/2 electrons (229.7–230.0 eV) from the molybdenum-bearing ferrites have suggested that MO is in the valence state of +4 in a lattice of the spinel type.