STUDY OF ENVIRONMENTAL VARIATION OF FE-3+ IONS WITH TEMPERATURE

Colloidal solute β-FeOOH are diffused and the Mössbauer spectrum of the sol at room temperature shows a paramagnetic doublet with broadened line width. At low temperatures the particles become magnetic which can be explained from the measurements of the site occupancy ratio. The symmetry in the anionic environment is evidenced in the room temperature spectrum while the low temperature study shows the lattice contraction only. On rapid cooling, the environmental change in the lattice takes place because of sudden removal of anions from the lattice showing the dependence of the environments of the Fe3+ ions on the degree of coordination. © 1990.