PYROCHLORE-LIKE COMPOUNDS DERIVED FROM ANTIMONIC ACID

Highly crystalline antimonic acid, H2Sb2O6.1.5H2O (CAA) with a pyrochl ore-like structure has been ion-exchanged with Fe3+ and Cd2+ to form H 1.34Fe0.22Sb2O6.1.5H2O (CAA/Fe) and H0.73Cd0.635Sb2O6.1.5H2O (CAA/Cd) phases. Thermal decomposition of these phases was studied by XRD, FTIR , TG, DSC and SEM. The final products, obtained by the thermal treatme nt of CAA/Fe and CAA/Ad at 1100-degrees-C, for 2 h, were FeSbO4 and Cd 2Sb2O7-x, respectively. The chemical homogeneity and phase purity for these compounds, and the temperature and time for reactions indicate t hat the use of adequate precursors has advantages, in comparison to co nventional solid-solid methods involving mixtures of oxides.