TmBO3 crystallizes in the orthorhombic Ama2 space group. Tm(1) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. B(1) is bonded in a trigonal planar geometry to one O(2) and two equivalent O(1) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 1-coordinate geometry to two equivalent Tm(1) and one B(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Tm(1) and one B(1) atom.
TmBO3 crystallizes in the orthorhombic Ama2 space group. Tm(1) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. Both Tm(1)-O(2) bond lengths are 2.22 Å. There are two shorter (2.31 Å) and two longer (2.32 Å) Tm(1)-O(1) bond lengths. B(1) is bonded in a trigonal planar geometry to one O(2) and two equivalent O(1) atoms. The B(1)-O(2) bond length is 1.37 Å. Both B(1)-O(1) bond lengths are 1.40 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 1-coordinate geometry to two equivalent Tm(1) and one B(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Tm(1) and one B(1) atom.