KAlF4 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one F(5), two equivalent F(3), and four equivalent F(2) atoms. In the second K site, K(2) is bonded in a 6-coordinate geometry to two equivalent F(2) and four equivalent F(3) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent F(2), two equivalent F(4), and two equivalent F(5) atoms to form corner-sharing AlF6 octahedra. The corner-sharing octahedral tilt angles range from 9-21°. In the second Al site, Al(2) is bonded to two equivalent F(1), two equivalent F(3), and two equivalent F(4) atoms to form corner-sharing AlF6 octahedra. The corner-sharing octahedral tilt angles range from 9-20°. There are five inequivalent F sites. In the first F site, F(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Al(2) atoms. In the second F site, F(2) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one Al(1) atom. In the third F site, F(3) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one Al(2) atom. In the fourth F site, F(4) is bonded in a linear geometry to one Al(1) and one Al(2) atom. In the fifth F site, F(5) is bonded in a distorted bent 150 degrees geometry to one K(1) and two equivalent Al(1) atoms.
KAlF4 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one F(5), two equivalent F(3), and four equivalent F(2) atoms. The K(1)-F(5) bond length is 3.02 Å. Both K(1)-F(3) bond lengths are 2.61 Å. There are two shorter (2.61 Å) and two longer (2.62 Å) K(1)-F(2) bond lengths. In the second K site, K(2) is bonded in a 6-coordinate geometry to two equivalent F(2) and four equivalent F(3) atoms. Both K(2)-F(2) bond lengths are 2.63 Å. All K(2)-F(3) bond lengths are 2.63 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent F(2), two equivalent F(4), and two equivalent F(5) atoms to form corner-sharing AlF6 octahedra. The corner-sharing octahedral tilt angles range from 9-21°. Both Al(1)-F(2) bond lengths are 1.76 Å. Both Al(1)-F(4) bond lengths are 1.84 Å. Both Al(1)-F(5) bond lengths are 1.84 Å. In the second Al site, Al(2) is bonded to two equivalent F(1), two equivalent F(3), and two equivalent F(4) atoms to form corner-sharing AlF6 octahedra. The corner-sharing octahedral tilt angles range from 9-20°. Both Al(2)-F(1) bond lengths are 1.84 Å. Both Al(2)-F(3) bond lengths are 1.76 Å. Both Al(2)-F(4) bond lengths are 1.84 Å. There are five inequivalent F sites. In the first F site, F(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Al(2) atoms. In the second F site, F(2) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one Al(1) atom. In the third F site, F(3) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one Al(2) atom. In the fourth F site, F(4) is bonded in a linear geometry to one Al(1) and one Al(2) atom. In the fifth F site, F(5) is bonded in a distorted bent 150 degrees geometry to one K(1) and two equivalent Al(1) atoms.