Materials Data on Cs2NaAl3F12 by Materials Project
Cs2NaAl3F12 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Cs1+ is bonded in a 6-coordinate geometry to fifteen F1- atoms. There are a spread of Cs–F bond distances ranging from 3.06–3.61 Å. Na1+ is bonded to six equivalent F1- atoms to form NaF6 octahedra that share corners with six equivalent AlF6 octahedra. The corner-sharing octahedral tilt angles are 51°. All Na–F bond lengths are 2.33 Å. Al3+ is bonded to six F1- atoms to form AlF6 octahedra that share corners with two equivalent NaF6 octahedra and corners with four equivalent AlF6 octahedra. The corner-sharing octahedra tilt angles range from 33–51°. There is two shorter (1.78 Å) and four longer (1.86 Å) Al–F bond length. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a 2-coordinate geometry to three equivalent Cs1+, one Na1+, and one Al3+ atom. In the second F1- site, F1- is bonded in a bent 150 degrees geometry to two equivalent Cs1+ and two equivalent Al3+ atoms.