Ta5Pb11O26 crystallizes in the monoclinic C2/m space group. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form TaO6 octahedra that share corners with two equivalent Pb(6)O6 octahedra, corners with four equivalent Ta(2)O6 octahedra, and edges with two equivalent Pb(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 35-48°. In the second Ta site, Ta(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(7) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Pb(6)O6 octahedra, and edges with two equivalent Pb(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 35-50°. In the third Ta site, Ta(3) is bonded to two equivalent O(3), two equivalent O(6), and two equivalent O(8) atoms to form TaO6 octahedra that share corners with two equivalent Ta(3)O6 octahedra, corners with two equivalent Pb(5)O6 octahedra, and corners with two equivalent Pb(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 30-48°. There are six inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to two equivalent O(1), two equivalent O(5), and four equivalent O(4) atoms to form distorted PbO8 hexagonal bipyramids that share edges with two equivalent Ta(1)O6 octahedra and edges with four equivalent Ta(2)O6 octahedra. In the second Pb site, Pb(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(7), one O(8), and one O(9) atom. In the third Pb site, Pb(3) is bonded in a 5-coordinate geometry to one O(5), two equivalent O(3), and two equivalent O(7) atoms. In the fourth Pb site, Pb(4) is bonded in a 4-coordinate geometry to four equivalent O(8) atoms. In the fifth Pb site, Pb(5) is bonded to two equivalent O(9) and four equivalent O(8) atoms to form PbO6 octahedra that share corners with two equivalent Pb(6)O6 octahedra and corners with four equivalent Ta(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. In the sixth Pb site, Pb(6) is bonded to one O(2), one O(9), two equivalent O(3), and two equivalent O(7) atoms to form PbO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Pb(5)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, and corners with two equivalent Ta(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-55°. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Ta(2) and one Pb(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ta(1), one Pb(6), and two equivalent Pb(2) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Ta(3), one Pb(2), one Pb(3), and one Pb(6) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Ta(1), one Ta(2), and one Pb(1) atom. In the fifth O site, O(5) is bonded to one Pb(1), one Pb(3), and two equivalent Pb(2) atoms to form a mixture of edge and corner-sharing OPb4 tetrahedra. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to two equivalent Ta(3) atoms. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Ta(2), one Pb(2), one Pb(3), and one Pb(6) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Ta(3), one Pb(2), one Pb(4), and one Pb(5) atom. In the ninth O site, O(9) is bonded to one Pb(5), one Pb(6), and two equivalent Pb(2) atoms to form a mixture of edge and corner-sharing OPb4 tetrahedra.
Ta5Pb11O26 crystallizes in the monoclinic C2/m space group. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form TaO6 octahedra that share corners with two equivalent Pb(6)O6 octahedra, corners with four equivalent Ta(2)O6 octahedra, and edges with two equivalent Pb(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 35-48°. Both Ta(1)-O(2) bond lengths are 2.00 Å. All Ta(1)-O(4) bond lengths are 2.02 Å. In the second Ta site, Ta(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(7) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Pb(6)O6 octahedra, and edges with two equivalent Pb(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 35-50°. Both Ta(2)-O(1) bond lengths are 2.01 Å. Both Ta(2)-O(4) bond lengths are 2.01 Å. Both Ta(2)-O(7) bond lengths are 2.00 Å. In the third Ta site, Ta(3) is bonded to two equivalent O(3), two equivalent O(6), and two equivalent O(8) atoms to form TaO6 octahedra that share corners with two equivalent Ta(3)O6 octahedra, corners with two equivalent Pb(5)O6 octahedra, and corners with two equivalent Pb(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 30-48°. Both Ta(3)-O(3) bond lengths are 2.01 Å. Both Ta(3)-O(6) bond lengths are 1.99 Å. Both Ta(3)-O(8) bond lengths are 2.00 Å. There are six inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to two equivalent O(1), two equivalent O(5), and four equivalent O(4) atoms to form distorted PbO8 hexagonal bipyramids that share edges with two equivalent Ta(1)O6 octahedra and edges with four equivalent Ta(2)O6 octahedra. Both Pb(1)-O(1) bond lengths are 2.79 Å. Both Pb(1)-O(5) bond lengths are 2.52 Å. All Pb(1)-O(4) bond lengths are 2.79 Å. In the second Pb site, Pb(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(7), one O(8), and one O(9) atom. The Pb(2)-O(2) bond length is 2.77 Å. The Pb(2)-O(3) bond length is 2.72 Å. The Pb(2)-O(5) bond length is 2.33 Å. The Pb(2)-O(7) bond length is 2.71 Å. The Pb(2)-O(8) bond length is 2.68 Å. The Pb(2)-O(9) bond length is 2.51 Å. In the third Pb site, Pb(3) is bonded in a 5-coordinate geometry to one O(5), two equivalent O(3), and two equivalent O(7) atoms. The Pb(3)-O(5) bond length is 2.30 Å. Both Pb(3)-O(3) bond lengths are 2.63 Å. Both Pb(3)-O(7) bond lengths are 2.71 Å. In the fourth Pb site, Pb(4) is bonded in a 4-coordinate geometry to four equivalent O(8) atoms. All Pb(4)-O(8) bond lengths are 2.62 Å. In the fifth Pb site, Pb(5) is bonded to two equivalent O(9) and four equivalent O(8) atoms to form PbO6 octahedra that share corners with two equivalent Pb(6)O6 octahedra and corners with four equivalent Ta(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. Both Pb(5)-O(9) bond lengths are 2.18 Å. All Pb(5)-O(8) bond lengths are 2.19 Å. In the sixth Pb site, Pb(6) is bonded to one O(2), one O(9), two equivalent O(3), and two equivalent O(7) atoms to form PbO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Pb(5)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, and corners with two equivalent Ta(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-55°. The Pb(6)-O(2) bond length is 2.17 Å. The Pb(6)-O(9) bond length is 2.20 Å. Both Pb(6)-O(3) bond lengths are 2.22 Å. Both Pb(6)-O(7) bond lengths are 2.22 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Ta(2) and one Pb(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ta(1), one Pb(6), and two equivalent Pb(2) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Ta(3), one Pb(2), one Pb(3), and one Pb(6) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Ta(1), one Ta(2), and one Pb(1) atom. In the fifth O site, O(5) is bonded to one Pb(1), one Pb(3), and two equivalent Pb(2) atoms to form a mixture of edge and corner-sharing OPb4 tetrahedra. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to two equivalent Ta(3) atoms. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Ta(2), one Pb(2), one Pb(3), and one Pb(6) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Ta(3), one Pb(2), one Pb(4), and one Pb(5) atom. In the ninth O site, O(9) is bonded to one Pb(5), one Pb(6), and two equivalent Pb(2) atoms to form a mixture of edge and corner-sharing OPb4 tetrahedra.