Ta2Ge2O7 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 13-25°. In the second Ta site, Ta(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(7) atoms to form distorted corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 2-29°. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 4-coordinate geometry to one O(3) and three equivalent O(5) atoms. In the second Ge site, Ge(2) is bonded in a 4-coordinate geometry to one O(6), one O(7), and two equivalent O(1) atoms. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a see-saw-like geometry to one Ta(1), one Ta(2), and two equivalent Ge(2) atoms. In the second O site, O(2) is bonded in a linear geometry to two equivalent Ta(2) atoms. In the third O site, O(3) is bonded in a water-like geometry to one Ta(1) and one Ge(1) atom. In the fourth O site, O(4) is bonded in a linear geometry to one Ta(1) and one Ta(2) atom. In the fifth O site, O(5) is bonded to one Ta(1) and three equivalent Ge(1) atoms to form distorted corner-sharing OTaGe3 tetrahedra. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to two equivalent Ta(1) and one Ge(2) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to two equivalent Ta(2) and one Ge(2) atom.
Ta2Ge2O7 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 13-25°. The Ta(1)-O(1) bond length is 2.13 Å. The Ta(1)-O(3) bond length is 1.92 Å. The Ta(1)-O(4) bond length is 2.08 Å. The Ta(1)-O(5) bond length is 1.94 Å. Both Ta(1)-O(6) bond lengths are 2.00 Å. In the second Ta site, Ta(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(7) atoms to form distorted corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 2-29°. The Ta(2)-O(1) bond length is 2.20 Å. The Ta(2)-O(4) bond length is 1.87 Å. There is one shorter (1.86 Å) and one longer (2.23 Å) Ta(2)-O(2) bond length. Both Ta(2)-O(7) bond lengths are 2.01 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 4-coordinate geometry to one O(3) and three equivalent O(5) atoms. The Ge(1)-O(3) bond length is 2.01 Å. There is one shorter (2.09 Å) and two longer (2.47 Å) Ge(1)-O(5) bond lengths. In the second Ge site, Ge(2) is bonded in a 4-coordinate geometry to one O(6), one O(7), and two equivalent O(1) atoms. The Ge(2)-O(6) bond length is 2.15 Å. The Ge(2)-O(7) bond length is 2.06 Å. Both Ge(2)-O(1) bond lengths are 2.20 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a see-saw-like geometry to one Ta(1), one Ta(2), and two equivalent Ge(2) atoms. In the second O site, O(2) is bonded in a linear geometry to two equivalent Ta(2) atoms. In the third O site, O(3) is bonded in a water-like geometry to one Ta(1) and one Ge(1) atom. In the fourth O site, O(4) is bonded in a linear geometry to one Ta(1) and one Ta(2) atom. In the fifth O site, O(5) is bonded to one Ta(1) and three equivalent Ge(1) atoms to form distorted corner-sharing OTaGe3 tetrahedra. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to two equivalent Ta(1) and one Ge(2) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to two equivalent Ta(2) and one Ge(2) atom.