Materials Data on La8MgAl7O24 by Materials Project

Abstract

MgLa8Al7O24 is (Cubic) Perovskite-derived structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Mg is bonded to six equivalent O atoms to form MgO6 octahedra that share corners with six equivalent AlO6 octahedra and faces with eight equivalent LaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Mg–O bond lengths are 2.00 Å. La is bonded to twelve O atoms to form LaO12 cuboctahedra that share corners with twelve equivalent LaO12 cuboctahedra, faces with six equivalent LaO12 cuboctahedra, a faceface with one MgO6 octahedra, and faces with seven AlO6 octahedra. There are a spread of La–O bond distances ranging from 2.70–2.72 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with four equivalent AlO6 octahedra, and faces with eight equivalent LaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There is two shorter (1.84 Å) and four longer (1.93 Å) Al–O bond length. In the second Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with six AlO6 octahedra and faces with eight equivalent LaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There is four shorter (1.90 Å) and two longer (1.92 Å) Al–O bond length. In the third Al site, Al is bonded to six equivalent O atoms to form AlO6 octahedra that share corners with six equivalent AlO6 octahedra and faces with eight equivalent LaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Al–O bond lengths are 1.92 Å. There are three inequivalent O sites. In the first O site, O is bonded in a distorted linear geometry to one Mg, four equivalent La, and one Al atom. In the second O site, O is bonded in a distorted linear geometry to four equivalent La and two Al atoms. In the third O site, O is bonded in a distorted linear geometry to four equivalent La and two Al atoms.