Materials Data on CsAlF4 by Materials Project
CsAlF4 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of Cs–F bond distances ranging from 2.81–3.33 Å. In the second Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to eight equivalent F1- atoms. All Cs–F bond lengths are 3.13 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six F1- atoms to form corner-sharing AlF6 octahedra. The corner-sharing octahedra tilt angles range from 1–33°. There are a spread of Al–F bond distances ranging from 1.78–1.92 Å. In the second Al3+ site, Al3+ is bonded to six F1- atoms to form corner-sharing AlF6 octahedra. The corner-sharing octahedral tilt angles are 29°. There is two shorter (1.77 Å) and four longer (1.86 Å) Al–F bond length. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a linear geometry to two equivalent Al3+ atoms. In the second F1- site, F1- is bonded in a distorted single-bond geometry to two equivalent Cs1+ and one Al3+ atom. In the third F1- site, F1- is bonded in a bent 150 degrees geometry to two equivalent Cs1+ and two equivalent Al3+ atoms. In the fourth F1- site, F1- is bonded in a bent 150 degrees geometry to two equivalent Cs1+ and two Al3+ atoms. In the fifth F1- site, F1- is bonded in a single-bond geometry to four Cs1+ and one Al3+ atom.