Materials Data on K2AlF5 by Materials Project
K2AlF5 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. K1+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are eight shorter (2.86 Å) and two longer (3.02 Å) K–F bond lengths. Al3+ is bonded to six F1- atoms to form corner-sharing AlF6 octahedra. The corner-sharing octahedral tilt angles are 0°. There is four shorter (1.81 Å) and two longer (1.88 Å) Al–F bond length. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted single-bond geometry to four equivalent K1+ and one Al3+ atom. In the second F1- site, F1- is bonded in a linear geometry to four equivalent K1+ and two equivalent Al3+ atoms.
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