Pyrochlore-Like Solid Solutions in the Y2O3–Fe2O3–Ta2O5–WO3 System

The aim of this work was to prepare and characterize the compound Y2Fe4/3W2/3O7 and pyrochlore-like solid solutions in the Y2O3–Fe2O3–Ta2O5–WO3 system. The Y2Fe4/3W2/3O7 preparation method was developed based on the citrate process. The compound was found to have a pyrochlore-like layered structure described by space group R 3. Heat capacity measurements showed that Y2Fe4/3W2/3O7, unlike Y2FeTaO7, does not have polymorphic transitions over the entire temperature range from 25 to 1460°C. The xY2FeTaO– (1–x) Y2Fe4/3W2/3O7 continuous solid solutions and limited xY1. 85Fe1. 15TaO7‒ (1‒x) Y2Fe4/3W2/3O7 solid solutions, where x = 0. 7–1, were shown to exist. The Y2xFe4/3+x W2/3O7 solid solution was not realized. The IR and Raman spectra of the prepared solid solutions were considered. The absorption edge positions were determined.