Phase Equilibria Involving Solid Solutions in the Li–Eu–O System

Abstract

Phase equilibria involving solid solutions in the Li–Eu–O system in an oxidizing, inert, and reducing atmospheres during annealing mixtures of various precursors subjected to preliminary mechanochemical activation at temperatures of 400–1100°C and partial pressures~ 21 and 0.01 kPa and ~ 5 kPa have been studied by X-ray powder diffraction and thermogravimetry. The solubility of lithium in EuO has been first estimated, which is no less than 50–60%. For Eu2O3 and, it is 30% of the total amount of cations. Along with LiEuO2, the formation of crystalline mixed-valent (EuII + EuIII) phases LiEu3O4 and Li2Eu5O8 has been confirmed. The thermal behavior of solid solutions Eu1 – xLixO1 – δ based on europium monoxide and Li1 + yEu3O4 – γ in air has been studied. The concentration phase diagram of the Li–Eu–O system has been constructed.