Materials Data on CaAl2(OF3)2 by Materials Project
CaAl2(OF3)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ca is bonded in a 8-coordinate geometry to two equivalent O and six F atoms. Both Ca–O bond lengths are 2.53 Å. There are a spread of Ca–F bond distances ranging from 2.23–2.50 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to two equivalent O and four F atoms to form edge-sharing AlO2F4 octahedra. Both Al–O bond lengths are 1.93 Å. All Al–F bond lengths are 1.84 Å. In the second Al site, Al is bonded to two equivalent O and four F atoms to form distorted edge-sharing AlO2F4 octahedra. Both Al–O bond lengths are 1.95 Å. There is two shorter (1.74 Å) and two longer (1.90 Å) Al–F bond length. O is bonded in a distorted trigonal non-coplanar geometry to one Ca and two Al atoms. There are three inequivalent F sites. In the first F site, F is bonded in a water-like geometry to two Al atoms. In the second F site, F is bonded in a 3-coordinate geometry to two equivalent Ca and one Al atom. In the third F site, F is bonded in a bent 150 degrees geometry to one Ca and one Al atom.