Tb11O20 crystallizes in the triclinic P-1 space group. There are six inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to two equivalent O(1), two equivalent O(5), and two equivalent O(8) atoms to form a mixture of distorted corner and edge-sharing TbO6 octahedra. In the second Tb site, Tb(2) is bonded to one O(5), one O(7), one O(9), two equivalent O(1), and two equivalent O(4) atoms to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(4)O7 hexagonal pyramid,  a cornercorner with one Tb(1)O6 octahedra,  an edgeedge with one Tb(1)O6 octahedra, and edges with two equivalent Tb(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 57°. In the third Tb site, Tb(3) is bonded in a 7-coordinate geometry to one O(10), one O(2), one O(4), one O(7), one O(8), and two equivalent O(5) atoms. In the fourth Tb site, Tb(4) is bonded to one O(10), one O(2), one O(6), one O(8), one O(9), and two equivalent O(3) atoms to form distorted TbO7 hexagonal pyramids that share  a cornercorner with one Tb(1)O6 octahedra,  a cornercorner with one Tb(2)O7 pentagonal bipyramid, and  an edgeedge with one Tb(4)O7 hexagonal pyramid. The corner-sharing octahedral tilt angles are 54°. In the fifth Tb site, Tb(5) is bonded in a body-centered cubic geometry to one O(1), one O(2), one O(3), one O(4), one O(6), one O(7), one O(8), and one O(9) atom. In the sixth Tb site, Tb(6) is bonded in a body-centered cubic geometry to one O(2), one O(3), one O(7), one O(9), two equivalent O(10), and two equivalent O(6) atoms. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Tb(1), one Tb(5), and two equivalent Tb(2) atoms to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the second O site, O(2) is bonded to one Tb(3), one Tb(4), one Tb(5), and one Tb(6) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the third O site, O(3) is bonded to one Tb(5), one Tb(6), and two equivalent Tb(4) atoms to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the fourth O site, O(4) is bonded to one Tb(3), one Tb(5), and two equivalent Tb(2) atoms to form a mixture of distorted corner and edge-sharing OTb4 tetrahedra. In the fifth O site, O(5) is bonded to one Tb(1), one Tb(2), and two equivalent Tb(3) atoms to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the sixth O site, O(6) is bonded to one Tb(4), one Tb(5), and two equivalent Tb(6) atoms to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the seventh O site, O(7) is bonded to one Tb(2), one Tb(3), one Tb(5), and one Tb(6) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the eighth O site, O(8) is bonded to one Tb(1), one Tb(3), one Tb(4), and one Tb(5) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the ninth O site, O(9) is bonded to one Tb(2), one Tb(4), one Tb(5), and one Tb(6) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the tenth O site, O(10) is bonded to one Tb(3), one Tb(4), and two equivalent Tb(6) atoms to form a mixture of corner and edge-sharing OTb4 tetrahedra.
Tb11O20 crystallizes in the triclinic P-1 space group. There are six inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to two equivalent O(1), two equivalent O(5), and two equivalent O(8) atoms to form a mixture of distorted corner and edge-sharing TbO6 octahedra. Both Tb(1)-O(1) bond lengths are 2.30 Å. Both Tb(1)-O(5) bond lengths are 2.24 Å. Both Tb(1)-O(8) bond lengths are 2.26 Å. In the second Tb site, Tb(2) is bonded to one O(5), one O(7), one O(9), two equivalent O(1), and two equivalent O(4) atoms to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(4)O7 hexagonal pyramid,  a cornercorner with one Tb(1)O6 octahedra,  an edgeedge with one Tb(1)O6 octahedra, and edges with two equivalent Tb(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 57°. The Tb(2)-O(5) bond length is 2.30 Å. The Tb(2)-O(7) bond length is 2.32 Å. The Tb(2)-O(9) bond length is 2.31 Å. There is one shorter (2.33 Å) and one longer (2.46 Å) Tb(2)-O(1) bond length. There is one shorter (2.33 Å) and one longer (2.34 Å) Tb(2)-O(4) bond length. In the third Tb site, Tb(3) is bonded in a 7-coordinate geometry to one O(10), one O(2), one O(4), one O(7), one O(8), and two equivalent O(5) atoms. The Tb(3)-O(10) bond length is 2.38 Å. The Tb(3)-O(2) bond length is 2.39 Å. The Tb(3)-O(4) bond length is 2.27 Å. The Tb(3)-O(7) bond length is 2.29 Å. The Tb(3)-O(8) bond length is 2.28 Å. There is one shorter (2.29 Å) and one longer (2.46 Å) Tb(3)-O(5) bond length. In the fourth Tb site, Tb(4) is bonded to one O(10), one O(2), one O(6), one O(8), one O(9), and two equivalent O(3) atoms to form distorted TbO7 hexagonal pyramids that share  a cornercorner with one Tb(1)O6 octahedra,  a cornercorner with one Tb(2)O7 pentagonal bipyramid, and  an edgeedge with one Tb(4)O7 hexagonal pyramid. The corner-sharing octahedral tilt angles are 54°. The Tb(4)-O(10) bond length is 2.34 Å. The Tb(4)-O(2) bond length is 2.40 Å. The Tb(4)-O(6) bond length is 2.34 Å. The Tb(4)-O(8) bond length is 2.28 Å. The Tb(4)-O(9) bond length is 2.36 Å. There is one shorter (2.27 Å) and one longer (2.35 Å) Tb(4)-O(3) bond length. In the fifth Tb site, Tb(5) is bonded in a body-centered cubic geometry to one O(1), one O(2), one O(3), one O(4), one O(6), one O(7), one O(8), and one O(9) atom. The Tb(5)-O(1) bond length is 2.37 Å. The Tb(5)-O(2) bond length is 2.36 Å. The Tb(5)-O(3) bond length is 2.31 Å. The Tb(5)-O(4) bond length is 2.59 Å. The Tb(5)-O(6) bond length is 2.41 Å. The Tb(5)-O(7) bond length is 2.32 Å. The Tb(5)-O(8) bond length is 2.47 Å. The Tb(5)-O(9) bond length is 2.43 Å. In the sixth Tb site, Tb(6) is bonded in a body-centered cubic geometry to one O(2), one O(3), one O(7), one O(9), two equivalent O(10), and two equivalent O(6) atoms. The Tb(6)-O(2) bond length is 2.47 Å. The Tb(6)-O(3) bond length is 2.29 Å. The Tb(6)-O(7) bond length is 2.32 Å. The Tb(6)-O(9) bond length is 2.42 Å. There is one shorter (2.43 Å) and one longer (2.52 Å) Tb(6)-O(10) bond length. There is one shorter (2.34 Å) and one longer (2.44 Å) Tb(6)-O(6) bond length. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Tb(1), one Tb(5), and two equivalent Tb(2) atoms to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the second O site, O(2) is bonded to one Tb(3), one Tb(4), one Tb(5), and one Tb(6) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the third O site, O(3) is bonded to one Tb(5), one Tb(6), and two equivalent Tb(4) atoms to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the fourth O site, O(4) is bonded to one Tb(3), one Tb(5), and two equivalent Tb(2) atoms to form a mixture of distorted corner and edge-sharing OTb4 tetrahedra. In the fifth O site, O(5) is bonded to one Tb(1), one Tb(2), and two equivalent Tb(3) atoms to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the sixth O site, O(6) is bonded to one Tb(4), one Tb(5), and two equivalent Tb(6) atoms to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the seventh O site, O(7) is bonded to one Tb(2), one Tb(3), one Tb(5), and one Tb(6) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the eighth O site, O(8) is bonded to one Tb(1), one Tb(3), one Tb(4), and one Tb(5) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the ninth O site, O(9) is bonded to one Tb(2), one Tb(4), one Tb(5), and one Tb(6) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the tenth O site, O(10) is bonded to one Tb(3), one Tb(4), and two equivalent Tb(6) atoms to form a mixture of corner and edge-sharing OTb4 tetrahedra.