Ta2Te2O9 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(10), one O(3), one O(5), one O(6), and one O(9) atom to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-33°. In the second Ta site, Ta(2) is bonded to one O(2), one O(4), one O(5), one O(7), one O(8), and one O(9) atom to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-33°. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded in a distorted T-shaped geometry to one O(10), one O(6), and one O(8) atom. In the second Te site, Te(2) is bonded in a distorted T-shaped geometry to one O(1), one O(2), and one O(4) atom. There are ten inequivalent O sites. In the first O site, O(6) is bonded in a bent 150 degrees geometry to one Ta(1) and one Te(1) atom. In the second O site, O(7) is bonded in a linear geometry to two equivalent Ta(2) atoms. In the third O site, O(8) is bonded in a bent 150 degrees geometry to one Ta(2) and one Te(1) atom. In the fourth O site, O(9) is bonded in a bent 150 degrees geometry to one Ta(1) and one Ta(2) atom. In the fifth O site, O(10) is bonded in a bent 120 degrees geometry to one Ta(1) and one Te(1) atom. In the sixth O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Ta(1) and one Te(2) atom. In the seventh O site, O(2) is bonded in a bent 150 degrees geometry to one Ta(2) and one Te(2) atom. In the eighth O site, O(3) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the ninth O site, O(4) is bonded in a bent 150 degrees geometry to one Ta(2) and one Te(2) atom. In the tenth O site, O(5) is bonded in a bent 150 degrees geometry to one Ta(1) and one Ta(2) atom.
Ta2Te2O9 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(10), one O(3), one O(5), one O(6), and one O(9) atom to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-33°. The Ta(1)-O(1) bond length is 2.10 Å. The Ta(1)-O(10) bond length is 2.06 Å. The Ta(1)-O(3) bond length is 1.91 Å. The Ta(1)-O(5) bond length is 1.91 Å. The Ta(1)-O(6) bond length is 2.00 Å. The Ta(1)-O(9) bond length is 1.92 Å. In the second Ta site, Ta(2) is bonded to one O(2), one O(4), one O(5), one O(7), one O(8), and one O(9) atom to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-33°. The Ta(2)-O(2) bond length is 2.03 Å. The Ta(2)-O(4) bond length is 2.05 Å. The Ta(2)-O(5) bond length is 1.92 Å. The Ta(2)-O(7) bond length is 1.90 Å. The Ta(2)-O(8) bond length is 2.04 Å. The Ta(2)-O(9) bond length is 1.96 Å. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded in a distorted T-shaped geometry to one O(10), one O(6), and one O(8) atom. The Te(1)-O(10) bond length is 1.89 Å. The Te(1)-O(6) bond length is 1.86 Å. The Te(1)-O(8) bond length is 1.87 Å. In the second Te site, Te(2) is bonded in a distorted T-shaped geometry to one O(1), one O(2), and one O(4) atom. The Te(2)-O(1) bond length is 1.89 Å. The Te(2)-O(2) bond length is 1.86 Å. The Te(2)-O(4) bond length is 1.87 Å. There are ten inequivalent O sites. In the first O site, O(6) is bonded in a bent 150 degrees geometry to one Ta(1) and one Te(1) atom. In the second O site, O(7) is bonded in a linear geometry to two equivalent Ta(2) atoms. In the third O site, O(8) is bonded in a bent 150 degrees geometry to one Ta(2) and one Te(1) atom. In the fourth O site, O(9) is bonded in a bent 150 degrees geometry to one Ta(1) and one Ta(2) atom. In the fifth O site, O(10) is bonded in a bent 120 degrees geometry to one Ta(1) and one Te(1) atom. In the sixth O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Ta(1) and one Te(2) atom. In the seventh O site, O(2) is bonded in a bent 150 degrees geometry to one Ta(2) and one Te(2) atom. In the eighth O site, O(3) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the ninth O site, O(4) is bonded in a bent 150 degrees geometry to one Ta(2) and one Te(2) atom. In the tenth O site, O(5) is bonded in a bent 150 degrees geometry to one Ta(1) and one Ta(2) atom.