A STRUCTURAL STUDY OF THE INCORPORATION OF SILICA INTO SODIUM FERRITES, NA1-X[FE1-XSIXO2], X = 0 TO 0.20

Rietveld refinements of X-ray powder intensity data have been performed for solid solution phases along the NaFeO2-SiO2 join. Five compositions Na1-x[Fe1-xSixO2] with x = 0 to 0.10 (βss, isostructural with β-NaFeO2) and four with x = 0.125 to 0.20 (γ′ss, isostructural with KGaO2) were refined. The results were used to analyze the effect of incorporation of silica into NaFeO2 on the rotation of the cristobalite-type tetrahedral framework and the associated changes in the environment of the sodium atoms. In the γ′ss-solid solution series, there is partial ordering of iron and silicon in the tetrahedral framework, with an associated modulation of the sodium atom distribution.†Permanent address: Department of Inorganic Chemistry, University of Melbourne, Parkville, Victoria 3052, Australia. © 1990 Academic Press, Inc.