Mossbauer Spectroscopy, X-ray Diffraction and IR Spectroscopy of Oxide Precipitates Formed from FeSO4 Solution

Iron oxyhydroxides and oxides were precipitated from FeS04 solution at low oxygen content. The composition and structure, stoichiometry, particle size and nuclear magnetism of the precipitates were studied using Mossbauer spectroscopy, X-ray diffraction and IR spectroscopy. The standard iron oxyhydroxides and oxides were also characterized using the same instrumental techniques. The results have indicated a strong dependence of the chemical composition and structure of the precipitates on the [FeS04] i [NaOH] concentration ratio. a-FeOOH of poor crystallinity was isolated at low pH values. a-Fe203 was formed by internal crystallization of a-FeOOH. At 90 aC, a mixture of Fe(OH)2iFe(OHh was transformed, with the time of heating, to nonstoichiometric Fe304, a-FeOOH and further to a-Fe203. Nonstoichiometric Fe304 was the final precipitation product in suspension with the [Fe2+]i [NaOH] stoichiometric ratio. The importance of these results for the corrosion science of steel in the presence of sulfates has been discussed

Mossbauer Spectra of Iron(III) Iodate and Periodates

The Mossbauer spectra of iron(III) iodate and periodate are studied at room temperature. The spectrum of iron(III) iodate shows a single line of absorption, while that of iron(III) periodate exhibits quadrupole splitting. The results are discussed in terms of ionic character and covalency of the chemical bond between iron(III) and oxy-anfons