SOLID SOLUTIONS WITH PYROCHLORE-LIKE STRUCTURE IN THE YO–FeO–TaO–WO SYSTEM

The aim of this work is to synthesize and study the properties of the compound YFeWO, and pyrochlore-like solid solutions in the YO–FeO–TaO–WO system. A method for obtaining YFeWO has been developed based on the citrate method. It has been established for the first time that the compound has a layered pyrochlore-like structure described by sp. gr. . A study of the heat capacity of YFeWO showed that, unlike YFeTaO, the compound does not have polymorphic transitions in the entire temperature range of 25–1460°C. The existence of a continuous solid solution xYFeTaO–(1–x)YFeWO, as well as a limited solid solution xYFeTaO–(1–x)YFeWO, where x = 0.7–1, is shown. It was found that a solid solution of YFeWO is not realized. The IR and Raman spectra of synthesized solid solutions are considered. The position of their absorption edge is determined.