DOE OSTI2020
CaFeTi2O6 crystallizes in the tetragonal P4_2/nmc space group. The structure is three-dimensional. Ca2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ca–O bond distances ranging from 2.36–2.75 Å. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six equivalent TiO6 octahedra and corners with two equivalent FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 30–37°. There are a spread of Ti–O bond distances ranging from 1.96–2.00 Å. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to four equivalent O2- atoms to form distorted FeO4 tetrahedra that share corners with eight equivalent TiO6 octahedra. The corner-sharing octahedral tilt angles are 73°. All Fe–O bond lengths are 2.08 Å. In the second Fe2+ site, Fe2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Fe–O bond lengths are 2.07 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+, two equivalent Ti4+, and one Fe2+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+ and two equivalent Ti4+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two equivalent Ti4+, and one Fe2+ atom.