The preparation and characterization of iron trihydroxide, Fe(OH)3

Iron trihydroxide has been prepared by the oxidation of FeSO 4 with [Co(III)(en)(dien)] 2 O 2 [ClO 4 ] 4 , [Co(III)(tetraen)] 2 O 2 [ClO 4 ] 4 , and H 2 O 2 in acid solution. These materials have been characterized by DTA, magnetic susceptibility, Mössbauer spectroscopy. X-ray powder diffraction, and electron microscopy. Particle sizes are found to be ~80 Å in diameter, but in the case of the (tetraen) preparation we find needle-like crystallites ~1200 Å × 400 Å × 50 Å in size. The magnitudes of the hyperfine fields follow the particle size variation. These materials have quite a different behaviour from the Fe(OH) 3 gels prepared from basic solution.