Preparation and crystallographic properties of the systems LaMn 1−xMn xO 3+λ and LaMn 1−xNi xO 3+λ JA-1106

Abstract

Lanthanum manganese oxides containing varying percentages of Mn +4 were prepared and their cell dimensions determined. Lanthanum manganese oxide, prepared under pure nitrogen, contained 0·02 per cent Mn +4. At room temperature it possessed orthorhombic symmetry and was the most distorted member of the series. The orthorhombic-to-rhombohedral transition points for members of this series have been determined, and the shape of the resulting curve interpreted on the basis of an ordering of four, coplanar empty orbitals of the Mn +3 ions and steric effects. The system LaNi x Mn 1− x O 3+ λ has been prepared and its crystallographic properties studied. La 2NiO 4, LaNiO 3 and an intermediate lanthanum nickel oxide were prepared and their X-ray data are given.