No abstract

Crystal structure of b-phase of iron-oxyhydroxide (Akaganeite) with different chlorine occupancy was studied by X-ray diffraction with Rietveld analysis. The structure depends on chlorine occupancy, u in tunnel sites of the phase. The crystal system was assigned to monoclinic (I2/m) throughout u range whereas the lattice and structure parameters changed with u. The chemical formula was estimated to be Fe(0:25 u 0:56 and w ' 0:2) where w denotes fraction of water molecules in tunnel sites. A sample with u ¼ 0:44 showed the highest crystal symmetry throughout the u range. The u-dependence of some structural parameters was discussed from the view point of oxygen displacements.