δ-FeO(OH) and its solid solutions - Part 1 Preparation and crystal chemistry

δ-FeO(OH)-type solid solutions have been synthesized with compositions Fe1-xMxO1-x(OH)1+x ranging up to x=0.10 for M=Ca, x=0.35 for M=Mg or Cd and x=0.40 for M=Zn. The phases are characterized by X-ray diffraction and transmission electron microscope studies. A structural model giving satisfactory intensity agreement is postulated for Fe1-xZnxO1-x(OH)1+x. In this model, Zn2+ ions are situated in the 0 0 0 octahedral sites of space group D3d3-P-3 ml while the Fe3+ ions are almost equally distributed among both octahedral sites (0 0 0 and 0 0 1/2). © 1979 Chapman and Hall Ltd.