Materials Data on AlCuO4F by Materials Project
CuAlO4F crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Cu is bonded to five O atoms to form CuO5 square pyramids that share corners with three AlO2F4 octahedra and edges with two equivalent CuO5 square pyramids. The corner-sharing octahedra tilt angles range from 48–59°. There are a spread of Cu–O bond distances ranging from 1.89–2.03 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to two equivalent O and four equivalent F atoms to form AlO2F4 octahedra that share corners with two equivalent CuO5 square pyramids and edges with two equivalent AlO2F4 octahedra. Both Al–O bond lengths are 1.88 Å. All Al–F bond lengths are 1.87 Å. In the second Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four equivalent CuO5 square pyramids and edges with two equivalent AlO6 octahedra. There is two shorter (1.84 Å) and four longer (1.94 Å) Al–O bond length. There are four inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to one Cu and one Al atom. In the second O site, O is bonded in a trigonal planar geometry to two equivalent Cu and one Al atom. In the third O site, O is bonded in a 2-coordinate geometry to two equivalent Al and one O atom. The O–O bond length is 1.44 Å. In the fourth O site, O is bonded in a distorted trigonal non-coplanar geometry to two equivalent Cu and one O atom. F is bonded in a water-like geometry to two equivalent Al atoms.