Structural characterization of (Bi1-xGdx)14W2O27 (x = 0.00 and 0.05) synthesized via mechano-thermal treatment


Samples of (Bi1-xGdx)14W2O27 (x = 0 and 0.05) compounds were prepared via a combination of mechanochemical and thermal treatments upon a Bi2O3/WO3/Gd2O3 stoichiometric mixture of precursors. Phase evolution, as well as the determination of structural parameters in as-prepared compounds, were performed by XRD analysis. Rietveld refinement revealed that gadolinium ions are incorporated into the tetragonal structure of Bi14W2O27 with preference to occupy octahedrally coordinated Bi3+ sites. The Gd doping induced an increase in Bi sites coordination, i.e., the number of oxygens around Bi/Gd ions increased, which can be explained by the absence of 6s2 lone pair electrons in gadolinium ions.