Pyrochlore-like compounds derived from antimonic acid

Abstract

Highly crystalline antimonic acid, H₂Sb₂O₆·1.5H₂O (CAA) with a pyrochlore-like structure has been ion-exchanged with Fe³⁺ and Cd²⁺ to form H_1.34Fe_0.22Sb₂O₆·1.5H₂O (CAA/Fe) and H_0.73Cd_0.635Sb₂O₆·1.5H₂O (CAA/Cd) phases. Thermal decomposition of these phases was studied by XRD, FTIR, TG, DSC and SEM. The final products, obtained by the thermal treatment of CAA/Fe and CAA/Cd at 1100 °C, for 2 h, were FeSbO₄ and Cd₂Sb₂O_{7 –x}, respectively. The chemical homogeneity and phase purity for these compounds, and the temperature and time for reactions indicate that the use of adequate precursors has advantages, in comparison to conventional solid–solid methods involving mixtures of oxides.