CaAl2F8 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent F(1), two equivalent F(2), and four equivalent F(4) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent F(1), two equivalent F(2), and two equivalent F(3) atoms to form edge-sharing AlF6 octahedra. In the second Al site, Al(2) is bonded to two equivalent F(2), two equivalent F(3), and two equivalent F(4) atoms to form edge-sharing AlF6 octahedra. There are four inequivalent F sites. In the first F site, F(1) is bonded in a bent 150 degrees geometry to one Ca(1) and one Al(1) atom. In the second F site, F(2) is bonded in a distorted water-like geometry to one Ca(1), one Al(1), and one Al(2) atom. In the third F site, F(3) is bonded in a water-like geometry to one Al(1) and one Al(2) atom. In the fourth F site, F(4) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one Al(2) atom.
CaAl2F8 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent F(1), two equivalent F(2), and four equivalent F(4) atoms. Both Ca(1)-F(1) bond lengths are 2.22 Å. Both Ca(1)-F(2) bond lengths are 2.63 Å. There are two shorter (2.41 Å) and two longer (2.45 Å) Ca(1)-F(4) bond lengths. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent F(1), two equivalent F(2), and two equivalent F(3) atoms to form edge-sharing AlF6 octahedra. Both Al(1)-F(1) bond lengths are 1.74 Å. Both Al(1)-F(2) bond lengths are 1.95 Å. Both Al(1)-F(3) bond lengths are 1.85 Å. In the second Al site, Al(2) is bonded to two equivalent F(2), two equivalent F(3), and two equivalent F(4) atoms to form edge-sharing AlF6 octahedra. Both Al(2)-F(2) bond lengths are 1.88 Å. Both Al(2)-F(3) bond lengths are 1.83 Å. Both Al(2)-F(4) bond lengths are 1.83 Å. There are four inequivalent F sites. In the first F site, F(1) is bonded in a bent 150 degrees geometry to one Ca(1) and one Al(1) atom. In the second F site, F(2) is bonded in a distorted water-like geometry to one Ca(1), one Al(1), and one Al(2) atom. In the third F site, F(3) is bonded in a water-like geometry to one Al(1) and one Al(2) atom. In the fourth F site, F(4) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one Al(2) atom.