TmAlO3 crystallizes in the hexagonal P6_3/mmc space group. Tm(1) is bonded to six equivalent O(1) atoms to form distorted TmO6 octahedra that share corners with six equivalent Al(1)O5 trigonal bipyramids and edges with six equivalent Tm(1)O6 octahedra. Al(1) is bonded to two equivalent O(1) and three equivalent O(2) atoms to form AlO5 trigonal bipyramids that share corners with six equivalent Tm(1)O6 octahedra and corners with six equivalent Al(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 62°. There are two inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Tm(1) and one Al(1) atom to form a mixture of distorted edge and corner-sharing OTm3Al tetrahedra. In the second O site, O(2) is bonded in a trigonal planar geometry to three equivalent Al(1) atoms.
TmAlO3 crystallizes in the hexagonal P6_3/mmc space group. Tm(1) is bonded to six equivalent O(1) atoms to form distorted TmO6 octahedra that share corners with six equivalent Al(1)O5 trigonal bipyramids and edges with six equivalent Tm(1)O6 octahedra. All Tm(1)-O(1) bond lengths are 2.23 Å. Al(1) is bonded to two equivalent O(1) and three equivalent O(2) atoms to form AlO5 trigonal bipyramids that share corners with six equivalent Tm(1)O6 octahedra and corners with six equivalent Al(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 62°. Both Al(1)-O(1) bond lengths are 1.83 Å. All Al(1)-O(2) bond lengths are 1.98 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Tm(1) and one Al(1) atom to form a mixture of distorted edge and corner-sharing OTm3Al tetrahedra. In the second O site, O(2) is bonded in a trigonal planar geometry to three equivalent Al(1) atoms.