Materials Data on CaGdAlO4 by Materials Project
CaGdAlO4 is (La,Ba)CuO4-derived structured and crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. Ca2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ca–O bond distances ranging from 2.27–2.63 Å. Gd3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Gd–O bond distances ranging from 2.26–2.63 Å. Al3+ is bonded to six O2- atoms to form corner-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are a spread of Al–O bond distances ranging from 1.85–2.07 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ca2+, four equivalent Gd3+, and one Al3+ atom to form distorted OCaGd4Al octahedra that share corners with seventeen OCa2Gd2Al2 octahedra, edges with eight OCaGd4Al octahedra, and faces with four equivalent OCa2Gd2Al2 octahedra. The corner-sharing octahedra tilt angles range from 0–53°. In the second O2- site, O2- is bonded to four equivalent Ca2+, one Gd3+, and one Al3+ atom to form distorted OCa4GdAl octahedra that share corners with seventeen OCa2Gd2Al2 octahedra, edges with eight OCaGd4Al octahedra, and faces with four equivalent OCa2Gd2Al2 octahedra. The corner-sharing octahedra tilt angles range from 0–54°. In the third O2- site, O2- is bonded to two equivalent Ca2+, two equivalent Gd3+, and two equivalent Al3+ atoms to form a mixture of distorted face, edge, and corner-sharing OCa2Gd2Al2 octahedra. The corner-sharing octahedra tilt angles range from 7–54°.