Materials Data on K2AlOF5 by Materials Project
K2AlOF5 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. K is bonded in a 12-coordinate geometry to two equivalent O and nine F atoms. There are one shorter (3.02 Å) and one longer (3.16 Å) K–O bond lengths. There are a spread of K–F bond distances ranging from 2.73–3.05 Å. Al is bonded to six F atoms to form corner-sharing AlF6 octahedra. The corner-sharing octahedral tilt angles are 12°. There are a spread of Al–F bond distances ranging from 1.81–1.89 Å. O is bonded in a rectangular see-saw-like geometry to four equivalent K atoms. There are three inequivalent F sites. In the first F site, F is bonded in a distorted single-bond geometry to four equivalent K and one Al atom. In the second F site, F is bonded in a single-bond geometry to four equivalent K and one Al atom. In the third F site, F is bonded in a distorted linear geometry to two equivalent K and two equivalent Al atoms.