TmTaO4 crystallizes in the orthorhombic Cmc2_1 space group. Tm(1) is bonded in a 7-coordinate geometry to one O(1), three equivalent O(2), and three equivalent O(3) atoms. Ta(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 23-33°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Tm(1) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded to three equivalent Tm(1) and one Ta(1) atom to form a mixture of corner and edge-sharing OTm3Ta tetrahedra. In the third O site, O(3) is bonded to three equivalent Tm(1) and one Ta(1) atom to form a mixture of distorted corner and edge-sharing OTm3Ta trigonal pyramids. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Ta(1) atoms.
TmTaO4 crystallizes in the orthorhombic Cmc2_1 space group. Tm(1) is bonded in a 7-coordinate geometry to one O(1), three equivalent O(2), and three equivalent O(3) atoms. The Tm(1)-O(1) bond length is 2.49 Å. There is one shorter (2.20 Å) and two longer (2.23 Å) Tm(1)-O(2) bond lengths. There is one shorter (2.33 Å) and two longer (2.54 Å) Tm(1)-O(3) bond lengths. Ta(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 23-33°. The Ta(1)-O(2) bond length is 2.15 Å. The Ta(1)-O(3) bond length is 1.97 Å. Both Ta(1)-O(1) bond lengths are 1.97 Å. There is one shorter (1.88 Å) and one longer (2.05 Å) Ta(1)-O(4) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Tm(1) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded to three equivalent Tm(1) and one Ta(1) atom to form a mixture of corner and edge-sharing OTm3Ta tetrahedra. In the third O site, O(3) is bonded to three equivalent Tm(1) and one Ta(1) atom to form a mixture of distorted corner and edge-sharing OTm3Ta trigonal pyramids. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Ta(1) atoms.