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

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 Eu 2 O 3 and , it is 30% of the total amount of cations. Along with LiEuO 2 , the formation of crystalline mixed-valent (Eu II + Eu III ) phases LiEu 3 O 4 and Li 2 Eu 5 O 8 has been confirmed. The thermal behavior of solid solutions Eu 1 – x Li x O 1 – δ based on europium monoxide and Li 1 + y Eu 3 O 4 – γ in air has been studied. The concentration phase diagram of the Li–Eu–O system has been constructed.