Preparation of a new type of nonstoichiometric rare-earth oxide

Abstract

Previously unreported partially reduced rare-earth oxides of the type REO χ, 1·450 < x < 1·500, were prepared by vacuum melting the normal rare-earth sesquioxides, RE 2O 3, and by co-distilling and co-melting the rare-earth metals with their respective sesquioxides. The oxygen-to-metal ratio of these materials was determined from the weight gained upon reoxidation to the sesquioxide, REO 1·500. The nature of these materials was explored through X-ray diffraction and density measurements of the cubic (C-type) forms of GdO 1·495, YO 1·489, and LuO 1·485. The X-ray and density data showed that the nonstoichiometry obtained in the partially reduced rare-earth sesquioxides could be attributed entirely to the loss of oxygen from the lattice. The loss of oxygen results in the formation of vacancies which greatly affect the properties of these materials.