Materials Data on MgAlF5 by Materials Project
MgF2AlF3 crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two AlF3 ribbons oriented in the (1, 0, 0) direction and two MgF2 ribbons oriented in the (1, 0, 0) direction. In each AlF3 ribbon, Al3+ is bonded in a square co-planar geometry to four F1- atoms. There is two shorter (1.67 Å) and two longer (1.70 Å) Al–F bond length. There are two 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 single-bond geometry to one Al3+ atom. In each MgF2 ribbon, Mg2+ is bonded in a distorted rectangular see-saw-like geometry to four equivalent F1- atoms. All Mg–F bond lengths are 2.08 Å. F1- is bonded in a water-like geometry to two equivalent Mg2+ atoms.