Materials Data on MgF3 by Materials Project
MgF3 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Mg is bonded to twelve F atoms to form a mixture of edge, corner, and face-sharing MgF12 cuboctahedra. There are four shorter (2.22 Å) and eight longer (2.52 Å) Mg–F bond lengths. There are two inequivalent F sites. In the first F site, F is bonded in a square co-planar geometry to four equivalent Mg atoms. In the second F site, F is bonded in a 4-coordinate geometry to four equivalent Mg atoms.