TmF3 is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. Tm(1) is bonded to four equivalent F(2) and eight equivalent F(1) atoms to form a mixture of face, corner, and edge-sharing TmF12 cuboctahedra. There are two inequivalent F sites. In the first F site, F(1) is bonded to four equivalent Tm(1) atoms to form a mixture of corner and edge-sharing FTm4 tetrahedra. In the second F site, F(2) is bonded in a square co-planar geometry to four equivalent Tm(1) atoms.
TmF3 is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. Tm(1) is bonded to four equivalent F(2) and eight equivalent F(1) atoms to form a mixture of face, corner, and edge-sharing TmF12 cuboctahedra. All Tm(1)-F(2) bond lengths are 2.51 Å. All Tm(1)-F(1) bond lengths are 2.37 Å. There are two inequivalent F sites. In the first F site, F(1) is bonded to four equivalent Tm(1) atoms to form a mixture of corner and edge-sharing FTm4 tetrahedra. In the second F site, F(2) is bonded in a square co-planar geometry to four equivalent Tm(1) atoms.