Materials Data on BaTmFe4O7 by Materials Project
BaTmFe4O7 crystallizes in the tetragonal I-4 space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.83 Å) and four longer (3.24 Å) Ba–O bond lengths. Tm3+ is bonded to six O2- atoms to form TmO6 octahedra that share corners with twelve equivalent FeO4 tetrahedra. There are two shorter (2.24 Å) and four longer (2.25 Å) Tm–O bond lengths. Fe+2.25+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three equivalent TmO6 octahedra and corners with six equivalent FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–60°. There are a spread of Fe–O bond distances ranging from 1.95–2.06 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+, one Tm3+, and two equivalent Fe+2.25+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ba2+, one Tm3+, and two equivalent Fe+2.25+ atoms. In the third O2- site, O2- is bonded in a tetrahedral geometry to four equivalent Fe+2.25+ atoms.