Phase Equilibria in the Li–Mn–Eu–O System

Phase equilibria in the Li–Mn–Eu–O system were studied for the first time in the temperature range 700–1000°С, and a concentration diagram was constructed within the Li–Mn–Eu triangle at an oxygen partial pressure of 21 kPa. It was shown that the LiEuO 2 –Li 2 MnO 3 section can be represented as quasi-binary, unlike the sections LiEuO 2 –LiMnO 2 and LiEuO 2 –LiMn 2 O 4 . It was determined that the isomorphic substitution of Eu for Mn in spinel LiMn 2 O 4 ( Fd m ) does not exceed 2 mol %, while Li 2 MnO 3 ( C 2/ m ) loses its single-phase character.