Y11Ta5O28 crystallizes in the triclinic P1 space group. There are eleven inequivalent Y sites. In the first Y site, Y(1) is bonded to one O(14), one O(16), one O(17), one O(21), one O(23), one O(6), and one O(9) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Y(9)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O8 hexagonal bipyramid,  an edgeedge with one Ta(3)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra, and edges with two equivalent Y(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 56°. In the second Y site, Y(2) is bonded to one O(1), one O(11), one O(12), one O(16), one O(23), one O(3), one O(4), and one O(8) atom to form distorted YO8 hexagonal bipyramids that share  an edgeedge with one Ta(2)O6 octahedra,  an edgeedge with one Ta(3)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra,  an edgeedge with one Ta(5)O6 octahedra, edges with two equivalent Ta(1)O6 octahedra,  an edgeedge with one Y(1)O7 pentagonal bipyramid, and  an edgeedge with one Y(10)O7 pentagonal bipyramid. In the third Y site, Y(3) is bonded to one O(14), one O(15), one O(17), one O(21), one O(26), one O(5), and one O(9) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  an edgeedge with one Ta(3)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra,  an edgeedge with one Y(11)O7 pentagonal bipyramid, and edges with two equivalent Y(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 46-54°. In the fourth Y site, Y(4) is bonded in a body-centered cubic geometry to one O(14), one O(19), one O(22), one O(24), one O(25), one O(27), one O(5), and one O(6) atom. In the fifth Y site, Y(5) is bonded in a 8-coordinate geometry to one O(10), one O(12), one O(21), one O(23), one O(26), one O(3), one O(7), and one O(8) atom. In the sixth Y site, Y(6) is bonded in a distorted body-centered cubic geometry to one O(11), one O(13), one O(17), one O(23), one O(26), one O(4), one O(7), and one O(8) atom. In the seventh Y site, Y(7) is bonded in a body-centered cubic geometry to one O(18), one O(20), one O(24), one O(25), one O(28), one O(5), one O(6), and one O(9) atom. In the eighth Y site, Y(8) is bonded to one O(10), one O(13), one O(18), one O(19), one O(2), one O(24), and one O(7) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  an edgeedge with one Ta(2)O6 octahedra,  an edgeedge with one Ta(5)O6 octahedra,  an edgeedge with one Y(9)O7 pentagonal bipyramid, and edges with two equivalent Y(10)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 46-55°. In the ninth Y site, Y(9) is bonded to one O(2), one O(20), one O(22), one O(24), one O(27), one O(28), and one O(6) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Y(1)O7 pentagonal bipyramid,  an edgeedge with one Ta(2)O6 octahedra,  an edgeedge with one Ta(5)O6 octahedra,  an edgeedge with one Y(8)O7 pentagonal bipyramid, and edges with two equivalent Y(11)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 50°. In the tenth Y site, Y(10) is bonded to one O(1), one O(10), one O(13), one O(18), one O(19), one O(25), and one O(8) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Y(11)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O8 hexagonal bipyramid,  an edgeedge with one Ta(2)O6 octahedra,  an edgeedge with one Ta(5)O6 octahedra, and edges with two equivalent Y(8)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 56°. In the eleventh Y site, Y(11) is bonded to one O(15), one O(20), one O(22), one O(25), one O(27), one O(28), and one O(5) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Y(10)O7 pentagonal bipyramid,  an edgeedge with one Ta(3)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra,  an edgeedge with one Y(3)O7 pentagonal bipyramid, and edges with two equivalent Y(9)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 50°. There are five inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(11), one O(12), one O(26), one O(3), one O(4), and one O(7) atom to form TaO6 octahedra that share  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Y(3)O7 pentagonal bipyramid,  a cornercorner with one Y(8)O7 pentagonal bipyramid, and edges with two equivalent Y(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-41°. In the second Ta site, Ta(2) is bonded to one O(1), one O(10), one O(18), one O(2), one O(28), and one O(3) atom to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(5)O6 octahedra,  a cornercorner with one Y(10)O7 pentagonal bipyramid,  a cornercorner with one Y(11)O7 pentagonal bipyramid,  a cornercorner with one Y(8)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O8 hexagonal bipyramid,  an edgeedge with one Y(10)O7 pentagonal bipyramid,  an edgeedge with one Y(8)O7 pentagonal bipyramid, and  an edgeedge with one Y(9)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 37-64°. In the third Ta site, Ta(3) is bonded to one O(12), one O(14), one O(15), one O(16), one O(21), and one O(22) atom to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra,  a cornercorner with one Y(1)O7 pentagonal bipyramid,  a cornercorner with one Y(3)O7 pentagonal bipyramid,  a cornercorner with one Y(9)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O8 hexagonal bipyramid,  an edgeedge with one Y(1)O7 pentagonal bipyramid,  an edgeedge with one Y(11)O7 pentagonal bipyramid, and  an edgeedge with one Y(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 38-64°. In the fourth Ta site, Ta(4) is bonded to one O(11), one O(15), one O(16), one O(17), one O(20), and one O(9) atom to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra,  a cornercorner with one Y(1)O7 pentagonal bipyramid,  a cornercorner with one Y(3)O7 pentagonal bipyramid,  a cornercorner with one Y(9)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O8 hexagonal bipyramid,  an edgeedge with one Y(1)O7 pentagonal bipyramid,  an edgeedge with one Y(11)O7 pentagonal bipyramid, and  an edgeedge with one Y(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 38-64°. In the fifth Ta site, Ta(5) is bonded to one O(1), one O(13), one O(19), one O(2), one O(27), and one O(4) atom to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra,  a cornercorner with one Y(10)O7 pentagonal bipyramid,  a cornercorner with one Y(11)O7 pentagonal bipyramid,  a cornercorner with one Y(8)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O8 hexagonal bipyramid,  an edgeedge with one Y(10)O7 pentagonal bipyramid,  an edgeedge with one Y(8)O7 pentagonal bipyramid, and  an edgeedge with one Y(9)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 37-64°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded to one Y(10), one Y(2), one Ta(2), and one Ta(5) atom to form OY2Ta2 tetrahedra that share  a cornercorner with one O(16)Y2Ta2 tetrahedra,  a cornercorner with one O(27)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(10)Y3Ta tetrahedra, corners with two equivalent O(13)Y3Ta tetrahedra, corners with two equivalent O(2)Y2Ta2 trigonal pyramids,  an edgeedge with one O(18)Y3Ta tetrahedra,  an edgeedge with one O(19)Y3Ta tetrahedra, and  an edgeedge with one O(8)Y4 tetrahedra. In the second O site, O(2) is bonded to one Y(8), one Y(9), one Ta(2), and one Ta(5) atom to form distorted OY2Ta2 trigonal pyramids that share  a cornercorner with one O(20)Y3Ta tetrahedra,  a cornercorner with one O(22)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra, corners with two equivalent O(1)Y2Ta2 tetrahedra, corners with two equivalent O(18)Y3Ta tetrahedra, corners with two equivalent O(19)Y3Ta tetrahedra,  an edgeedge with one O(10)Y3Ta tetrahedra,  an edgeedge with one O(13)Y3Ta tetrahedra,  an edgeedge with one O(27)Y3Ta tetrahedra, and  an edgeedge with one O(24)Y4 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Y(2), one Y(5), one Ta(1), and one Ta(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Y(2), one Y(6), one Ta(1), and one Ta(5) atom. In the fifth O site, O(5) is bonded to one Y(11), one Y(3), one Y(4), and one Y(7) atom to form OY4 tetrahedra that share  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(18)Y3Ta tetrahedra,  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(20)Y3Ta tetrahedra, corners with two equivalent O(22)Y3Ta tetrahedra, corners with two equivalent O(24)Y4 tetrahedra, corners with two equivalent O(6)Y4 tetrahedra,  an edgeedge with one O(14)Y3Ta tetrahedra,  an edgeedge with one O(27)Y3Ta tetrahedra,  an edgeedge with one O(9)Y3Ta tetrahedra,  an edgeedge with one O(25)Y4 tetrahedra, and  an edgeedge with one O(15)Y2Ta2 trigonal pyramid. In the sixth O site, O(6) is bonded to one Y(1), one Y(4), one Y(7), and one Y(9) atom to form OY4 tetrahedra that share  a cornercorner with one O(16)Y2Ta2 tetrahedra,  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(18)Y3Ta tetrahedra,  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(24)Y4 tetrahedra, corners with two equivalent O(20)Y3Ta tetrahedra, corners with two equivalent O(22)Y3Ta tetrahedra, corners with two equivalent O(25)Y4 tetrahedra, corners with two equivalent O(5)Y4 tetrahedra,  a cornercorner with one O(2)Y2Ta2 trigonal pyramid,  an edgeedge with one O(14)Y3Ta tetrahedra,  an edgeedge with one O(27)Y3Ta tetrahedra,  an edgeedge with one O(9)Y3Ta tetrahedra, and  an edgeedge with one O(24)Y4 tetrahedra. In the seventh O site, O(7) is bonded to one Y(5), one Y(6), one Y(8), and one Ta(1) atom to form OY3Ta tetrahedra that share  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(18)Y3Ta tetrahedra,  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(24)Y4 tetrahedra, corners with two equivalent O(23)Y4 tetrahedra, corners with two equivalent O(8)Y4 tetrahedra,  a cornercorner with one O(2)Y2Ta2 trigonal pyramid,  an edgeedge with one O(10)Y3Ta tetrahedra,  an edgeedge with one O(13)Y3Ta tetrahedra, and  an edgeedge with one O(26)Y3Ta tetrahedra. In the eighth O site, O(8) is bonded to one Y(10), one Y(2), one Y(5), and one Y(6) atom to form OY4 tetrahedra that share  a cornercorner with one O(16)Y2Ta2 tetrahedra,  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(18)Y3Ta tetrahedra,  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(26)Y3Ta tetrahedra, corners with two equivalent O(7)Y3Ta tetrahedra,  an edgeedge with one O(1)Y2Ta2 tetrahedra,  an edgeedge with one O(10)Y3Ta tetrahedra,  an edgeedge with one O(13)Y3Ta tetrahedra, and  an edgeedge with one O(23)Y4 tetrahedra. In the ninth O site, O(9) is bonded to one Y(1), one Y(3), one Y(7), and one Ta(4) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(18)Y3Ta tetrahedra,  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(24)Y4 tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(14)Y3Ta tetrahedra, corners with two equivalent O(21)Y3Ta tetrahedra, corners with two equivalent O(15)Y2Ta2 trigonal pyramids,  an edgeedge with one O(16)Y2Ta2 tetrahedra,  an edgeedge with one O(17)Y3Ta tetrahedra,  an edgeedge with one O(20)Y3Ta tetrahedra,  an edgeedge with one O(5)Y4 tetrahedra, and  an edgeedge with one O(6)Y4 tetrahedra. In the tenth O site, O(10) is bonded to one Y(10), one Y(5), one Y(8), and one Ta(2) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(18)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(24)Y4 tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(1)Y2Ta2 tetrahedra, corners with two equivalent O(13)Y3Ta tetrahedra, corners with two equivalent O(19)Y3Ta tetrahedra,  an edgeedge with one O(18)Y3Ta tetrahedra,  an edgeedge with one O(7)Y3Ta tetrahedra,  an edgeedge with one O(8)Y4 tetrahedra, and  an edgeedge with one O(2)Y2Ta2 trigonal pyramid. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Y(2), one Y(6), one Ta(1), and one Ta(4) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Y(2), one Y(5), one Ta(1), and one Ta(3) atom. In the thirteenth O site, O(13) is bonded to one Y(10), one Y(6), one Y(8), and one Ta(5) atom to form OY3Ta tetrahedra that share  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(27)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(24)Y4 tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(1)Y2Ta2 tetrahedra, corners with two equivalent O(10)Y3Ta tetrahedra, corners with two equivalent O(18)Y3Ta tetrahedra,  an edgeedge with one O(19)Y3Ta tetrahedra,  an edgeedge with one O(7)Y3Ta tetrahedra,  an edgeedge with one O(8)Y4 tetrahedra, and  an edgeedge with one O(2)Y2Ta2 trigonal pyramid. In the fourteenth O site, O(14) is bonded to one Y(1), one Y(3), one Y(4), and one Ta(3) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(27)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(24)Y4 tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(17)Y3Ta tetrahedra, corners with two equivalent O(9)Y3Ta tetrahedra, corners with two equivalent O(15)Y2Ta2 trigonal pyramids,  an edgeedge with one O(16)Y2Ta2 tetrahedra,  an edgeedge with one O(21)Y3Ta tetrahedra,  an edgeedge with one O(22)Y3Ta tetrahedra,  an edgeedge with one O(5)Y4 tetrahedra, and  an edgeedge with one O(6)Y4 tetrahedra. In the fifteenth O site, O(15) is bonded to one Y(11), one Y(3), one Ta(3), and one Ta(4) atom to form distorted OY2Ta2 trigonal pyramids that share  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(27)Y3Ta tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(16)Y2Ta2 tetrahedra, corners with two equivalent O(14)Y3Ta tetrahedra, corners with two equivalent O(9)Y3Ta tetrahedra,  an edgeedge with one O(17)Y3Ta tetrahedra,  an edgeedge with one O(20)Y3Ta tetrahedra,  an edgeedge with one O(21)Y3Ta tetrahedra,  an edgeedge with one O(22)Y3Ta tetrahedra, and  an edgeedge with one O(5)Y4 tetrahedra. In the sixteenth O site, O(16) is bonded to one Y(1), one Y(2), one Ta(3), and one Ta(4) atom to form OY2Ta2 tetrahedra that share  a cornercorner with one O(1)Y2Ta2 tetrahedra,  a cornercorner with one O(20)Y3Ta tetrahedra,  a cornercorner with one O(22)Y3Ta tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(17)Y3Ta tetrahedra, corners with two equivalent O(21)Y3Ta tetrahedra, corners with two equivalent O(15)Y2Ta2 trigonal pyramids,  an edgeedge with one O(14)Y3Ta tetrahedra,  an edgeedge with one O(9)Y3Ta tetrahedra, and  an edgeedge with one O(23)Y4 tetrahedra. In the seventeenth O site, O(17) is bonded to one Y(1), one Y(3), one Y(6), and one Ta(4) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(20)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(9)Y3Ta tetrahedra,  a cornercorner with one O(5)Y4 tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(16)Y2Ta2 tetrahedra, corners with two equivalent O(14)Y3Ta tetrahedra, corners with two equivalent O(21)Y3Ta tetrahedra,  an edgeedge with one O(26)Y3Ta tetrahedra,  an edgeedge with one O(9)Y3Ta tetrahedra,  an edgeedge with one O(23)Y4 tetrahedra, and  an edgeedge with one O(15)Y2Ta2 trigonal pyramid. In the eighteenth O site, O(18) is bonded to one Y(10), one Y(7), one Y(8), and one Ta(2) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(10)Y3Ta tetrahedra,  a cornercorner with one O(20)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(9)Y3Ta tetrahedra,  a cornercorner with one O(5)Y4 tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(13)Y3Ta tetrahedra, corners with two equivalent O(19)Y3Ta tetrahedra, corners with two equivalent O(2)Y2Ta2 trigonal pyramids,  an edgeedge with one O(1)Y2Ta2 tetrahedra,  an edgeedge with one O(10)Y3Ta tetrahedra,  an edgeedge with one O(24)Y4 tetrahedra, and  an edgeedge with one O(25)Y4 tetrahedra. In the nineteenth O site, O(19) is bonded to one Y(10), one Y(4), one Y(8), and one Ta(5) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(22)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(5)Y4 tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(10)Y3Ta tetrahedra, corners with two equivalent O(18)Y3Ta tetrahedra, corners with two equivalent O(2)Y2Ta2 trigonal pyramids,  an edgeedge with one O(1)Y2Ta2 tetrahedra,  an edgeedge with one O(13)Y3Ta tetrahedra,  an edgeedge with one O(27)Y3Ta tetrahedra,  an edgeedge with one O(24)Y4 tetrahedra, and  an edgeedge with one O(25)Y4 tetrahedra. In the twentieth O site, O(20) is bonded to one Y(11), one Y(7), one Y(9), and one Ta(4) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(16)Y2Ta2 tetrahedra,  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(18)Y3Ta tetrahedra, corners with two equivalent O(22)Y3Ta tetrahedra, corners with two equivalent O(27)Y3Ta tetrahedra, corners with two equivalent O(5)Y4 tetrahedra, corners with two equivalent O(6)Y4 tetrahedra,  a cornercorner with one O(2)Y2Ta2 trigonal pyramid,  an edgeedge with one O(9)Y3Ta tetrahedra,  an edgeedge with one O(24)Y4 tetrahedra,  an edgeedge with one O(25)Y4 tetrahedra, and  an edgeedge with one O(15)Y2Ta2 trigonal pyramid. In the twenty-first O site, O(21) is bonded to one Y(1), one Y(3), one Y(5), and one Ta(3) atom to form OY3Ta tetrahedra that share  a cornercorner with one O(10)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(22)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(5)Y4 tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(16)Y2Ta2 tetrahedra, corners with two equivalent O(17)Y3Ta tetrahedra, corners with two equivalent O(9)Y3Ta tetrahedra,  an edgeedge with one O(14)Y3Ta tetrahedra,  an edgeedge with one O(26)Y3Ta tetrahedra,  an edgeedge with one O(23)Y4 tetrahedra, and  an edgeedge with one O(15)Y2Ta2 trigonal pyramid. In the twenty-second O site, O(22) is bonded to one Y(11), one Y(4), one Y(9), and one Ta(3) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(16)Y2Ta2 tetrahedra,  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(27)Y3Ta tetrahedra, corners with two equivalent O(20)Y3Ta tetrahedra, corners with two equivalent O(5)Y4 tetrahedra, corners with two equivalent O(6)Y4 tetrahedra,  a cornercorner with one O(2)Y2Ta2 trigonal pyramid,  an edgeedge with one O(14)Y3Ta tetrahedra,  an edgeedge with one O(27)Y3Ta tetrahedra,  an edgeedge with one O(24)Y4 tetrahedra,  an edgeedge with one O(25)Y4 tetrahedra, and  an edgeedge with one O(15)Y2Ta2 trigonal pyramid. In the twenty-third O site, O(23) is bonded to one Y(1), one Y(2), one Y(5), and one Y(6) atom to form OY4 tetrahedra that share  a cornercorner with one O(1)Y2Ta2 tetrahedra,  a cornercorner with one O(10)Y3Ta tetrahedra,  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(9)Y3Ta tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(26)Y3Ta tetrahedra, corners with two equivalent O(7)Y3Ta tetrahedra,  an edgeedge with one O(16)Y2Ta2 tetrahedra,  an edgeedge with one O(17)Y3Ta tetrahedra,  an edgeedge with one O(21)Y3Ta tetrahedra, and  an edgeedge with one O(8)Y4 tetrahedra. In the twenty-fourth O site, O(24) is bonded to one Y(4), one Y(7), one Y(8), and one Y(9) atom to form OY4 tetrahedra that share  a cornercorner with one O(10)Y3Ta tetrahedra,  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(9)Y3Ta tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra, corners with two equivalent O(27)Y3Ta tetrahedra, corners with two equivalent O(25)Y4 tetrahedra, corners with two equivalent O(5)Y4 tetrahedra,  an edgeedge with one O(18)Y3Ta tetrahedra,  an edgeedge with one O(19)Y3Ta tetrahedra,  an edgeedge with one O(20)Y3Ta tetrahedra,  an edgeedge with one O(22)Y3Ta tetrahedra,  an edgeedge with one O(6)Y4 tetrahedra, and  an edgeedge with one O(2)Y2Ta2 trigonal pyramid. In the twenty-fifth O site, O(25) is bonded to one Y(10), one Y(11), one Y(4), and one Y(7) atom to form OY4 tetrahedra that share  a cornercorner with one O(1)Y2Ta2 tetrahedra,  a cornercorner with one O(10)Y3Ta tetrahedra,  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(9)Y3Ta tetrahedra,  a cornercorner with one O(5)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(27)Y3Ta tetrahedra, corners with two equivalent O(24)Y4 tetrahedra, corners with two equivalent O(6)Y4 tetrahedra,  a cornercorner with one O(15)Y2Ta2 trigonal pyramid,  an edgeedge with one O(18)Y3Ta tetrahedra,  an edgeedge with one O(19)Y3Ta tetrahedra,  an edgeedge with one O(20)Y3Ta tetrahedra,  an edgeedge with one O(22)Y3Ta tetrahedra, and  an edgeedge with one O(5)Y4 tetrahedra. In the twenty-sixth O site, O(26) is bonded to one Y(3), one Y(5), one Y(6), and one Ta(1) atom to form OY3Ta tetrahedra that share  a cornercorner with one O(10)Y3Ta tetrahedra,  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(9)Y3Ta tetrahedra,  a cornercorner with one O(5)Y4 tetrahedra, corners with two equivalent O(23)Y4 tetrahedra, corners with two equivalent O(8)Y4 tetrahedra,  a cornercorner with one O(15)Y2Ta2 trigonal pyramid,  an edgeedge with one O(17)Y3Ta tetrahedra,  an edgeedge with one O(21)Y3Ta tetrahedra, and  an edgeedge with one O(7)Y3Ta tetrahedra. In the twenty-seventh O site, O(27) is bonded to one Y(11), one Y(4), one Y(9), and one Ta(5) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(1)Y2Ta2 tetrahedra,  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(22)Y3Ta tetrahedra, corners with two equivalent O(20)Y3Ta tetrahedra, corners with two equivalent O(24)Y4 tetrahedra, corners with two equivalent O(25)Y4 tetrahedra,  a cornercorner with one O(15)Y2Ta2 trigonal pyramid,  an edgeedge with one O(19)Y3Ta tetrahedra,  an edgeedge with one O(22)Y3Ta tetrahedra,  an edgeedge with one O(5)Y4 tetrahedra,  an edgeedge with one O(6)Y4 tetrahedra, and  an edgeedge with one O(2)Y2Ta2 trigonal pyramid. In the twenty-eighth O site, O(28) is bonded in a 4-coordinate geometry to one Y(11), one Y(7), one Y(9), and one Ta(2) atom.
Y11Ta5O28 crystallizes in the triclinic P1 space group. There are eleven inequivalent Y sites. In the first Y site, Y(1) is bonded to one O(14), one O(16), one O(17), one O(21), one O(23), one O(6), and one O(9) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Y(9)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O8 hexagonal bipyramid,  an edgeedge with one Ta(3)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra, and edges with two equivalent Y(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 56°. The Y(1)-O(14) bond length is 2.36 Å. The Y(1)-O(16) bond length is 2.39 Å. The Y(1)-O(17) bond length is 2.31 Å. The Y(1)-O(21) bond length is 2.30 Å. The Y(1)-O(23) bond length is 2.37 Å. The Y(1)-O(6) bond length is 2.29 Å. The Y(1)-O(9) bond length is 2.36 Å. In the second Y site, Y(2) is bonded to one O(1), one O(11), one O(12), one O(16), one O(23), one O(3), one O(4), and one O(8) atom to form distorted YO8 hexagonal bipyramids that share  an edgeedge with one Ta(2)O6 octahedra,  an edgeedge with one Ta(3)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra,  an edgeedge with one Ta(5)O6 octahedra, edges with two equivalent Ta(1)O6 octahedra,  an edgeedge with one Y(1)O7 pentagonal bipyramid, and  an edgeedge with one Y(10)O7 pentagonal bipyramid. The Y(2)-O(1) bond length is 2.39 Å. The Y(2)-O(11) bond length is 2.60 Å. The Y(2)-O(12) bond length is 2.56 Å. The Y(2)-O(16) bond length is 2.39 Å. The Y(2)-O(23) bond length is 2.15 Å. The Y(2)-O(3) bond length is 2.58 Å. The Y(2)-O(4) bond length is 2.60 Å. The Y(2)-O(8) bond length is 2.16 Å. In the third Y site, Y(3) is bonded to one O(14), one O(15), one O(17), one O(21), one O(26), one O(5), and one O(9) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  an edgeedge with one Ta(3)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra,  an edgeedge with one Y(11)O7 pentagonal bipyramid, and edges with two equivalent Y(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 46-54°. The Y(3)-O(14) bond length is 2.30 Å. The Y(3)-O(15) bond length is 2.46 Å. The Y(3)-O(17) bond length is 2.42 Å. The Y(3)-O(21) bond length is 2.43 Å. The Y(3)-O(26) bond length is 2.30 Å. The Y(3)-O(5) bond length is 2.20 Å. The Y(3)-O(9) bond length is 2.29 Å. In the fourth Y site, Y(4) is bonded in a body-centered cubic geometry to one O(14), one O(19), one O(22), one O(24), one O(25), one O(27), one O(5), and one O(6) atom. The Y(4)-O(14) bond length is 2.60 Å. The Y(4)-O(19) bond length is 2.63 Å. The Y(4)-O(22) bond length is 2.60 Å. The Y(4)-O(24) bond length is 2.35 Å. The Y(4)-O(25) bond length is 2.32 Å. The Y(4)-O(27) bond length is 2.62 Å. The Y(4)-O(5) bond length is 2.35 Å. The Y(4)-O(6) bond length is 2.31 Å. In the fifth Y site, Y(5) is bonded in a 8-coordinate geometry to one O(10), one O(12), one O(21), one O(23), one O(26), one O(3), one O(7), and one O(8) atom. The Y(5)-O(10) bond length is 2.47 Å. The Y(5)-O(12) bond length is 2.67 Å. The Y(5)-O(21) bond length is 2.44 Å. The Y(5)-O(23) bond length is 2.26 Å. The Y(5)-O(26) bond length is 2.47 Å. The Y(5)-O(3) bond length is 2.85 Å. The Y(5)-O(7) bond length is 2.44 Å. The Y(5)-O(8) bond length is 2.25 Å. In the sixth Y site, Y(6) is bonded in a distorted body-centered cubic geometry to one O(11), one O(13), one O(17), one O(23), one O(26), one O(4), one O(7), and one O(8) atom. The Y(6)-O(11) bond length is 2.81 Å. The Y(6)-O(13) bond length is 2.42 Å. The Y(6)-O(17) bond length is 2.48 Å. The Y(6)-O(23) bond length is 2.26 Å. The Y(6)-O(26) bond length is 2.47 Å. The Y(6)-O(4) bond length is 2.68 Å. The Y(6)-O(7) bond length is 2.46 Å. The Y(6)-O(8) bond length is 2.26 Å. In the seventh Y site, Y(7) is bonded in a body-centered cubic geometry to one O(18), one O(20), one O(24), one O(25), one O(28), one O(5), one O(6), and one O(9) atom. The Y(7)-O(18) bond length is 2.59 Å. The Y(7)-O(20) bond length is 2.60 Å. The Y(7)-O(24) bond length is 2.35 Å. The Y(7)-O(25) bond length is 2.31 Å. The Y(7)-O(28) bond length is 2.64 Å. The Y(7)-O(5) bond length is 2.34 Å. The Y(7)-O(6) bond length is 2.32 Å. The Y(7)-O(9) bond length is 2.62 Å. In the eighth Y site, Y(8) is bonded to one O(10), one O(13), one O(18), one O(19), one O(2), one O(24), and one O(7) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  an edgeedge with one Ta(2)O6 octahedra,  an edgeedge with one Ta(5)O6 octahedra,  an edgeedge with one Y(9)O7 pentagonal bipyramid, and edges with two equivalent Y(10)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 46-55°. The Y(8)-O(10) bond length is 2.42 Å. The Y(8)-O(13) bond length is 2.43 Å. The Y(8)-O(18) bond length is 2.30 Å. The Y(8)-O(19) bond length is 2.30 Å. The Y(8)-O(2) bond length is 2.47 Å. The Y(8)-O(24) bond length is 2.21 Å. The Y(8)-O(7) bond length is 2.30 Å. In the ninth Y site, Y(9) is bonded to one O(2), one O(20), one O(22), one O(24), one O(27), one O(28), and one O(6) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Y(1)O7 pentagonal bipyramid,  an edgeedge with one Ta(2)O6 octahedra,  an edgeedge with one Ta(5)O6 octahedra,  an edgeedge with one Y(8)O7 pentagonal bipyramid, and edges with two equivalent Y(11)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 50°. The Y(9)-O(2) bond length is 2.45 Å. The Y(9)-O(20) bond length is 2.30 Å. The Y(9)-O(22) bond length is 2.29 Å. The Y(9)-O(24) bond length is 2.22 Å. The Y(9)-O(27) bond length is 2.34 Å. The Y(9)-O(28) bond length is 2.34 Å. The Y(9)-O(6) bond length is 2.29 Å. In the tenth Y site, Y(10) is bonded to one O(1), one O(10), one O(13), one O(18), one O(19), one O(25), and one O(8) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Y(11)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O8 hexagonal bipyramid,  an edgeedge with one Ta(2)O6 octahedra,  an edgeedge with one Ta(5)O6 octahedra, and edges with two equivalent Y(8)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 56°. The Y(10)-O(1) bond length is 2.39 Å. The Y(10)-O(10) bond length is 2.32 Å. The Y(10)-O(13) bond length is 2.31 Å. The Y(10)-O(18) bond length is 2.35 Å. The Y(10)-O(19) bond length is 2.36 Å. The Y(10)-O(25) bond length is 2.29 Å. The Y(10)-O(8) bond length is 2.36 Å. In the eleventh Y site, Y(11) is bonded to one O(15), one O(20), one O(22), one O(25), one O(27), one O(28), and one O(5) atom to form distorted YO7 pentagonal bipyramids that share  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Y(10)O7 pentagonal bipyramid,  an edgeedge with one Ta(3)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra,  an edgeedge with one Y(3)O7 pentagonal bipyramid, and edges with two equivalent Y(9)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 50°. The Y(11)-O(15) bond length is 2.45 Å. The Y(11)-O(20) bond length is 2.35 Å. The Y(11)-O(22) bond length is 2.35 Å. The Y(11)-O(25) bond length is 2.29 Å. The Y(11)-O(27) bond length is 2.29 Å. The Y(11)-O(28) bond length is 2.28 Å. The Y(11)-O(5) bond length is 2.23 Å. There are five inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(11), one O(12), one O(26), one O(3), one O(4), and one O(7) atom to form TaO6 octahedra that share  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Y(3)O7 pentagonal bipyramid,  a cornercorner with one Y(8)O7 pentagonal bipyramid, and edges with two equivalent Y(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-41°. The Ta(1)-O(11) bond length is 1.98 Å. The Ta(1)-O(12) bond length is 2.00 Å. The Ta(1)-O(26) bond length is 2.06 Å. The Ta(1)-O(3) bond length is 1.98 Å. The Ta(1)-O(4) bond length is 1.99 Å. The Ta(1)-O(7) bond length is 2.07 Å. In the second Ta site, Ta(2) is bonded to one O(1), one O(10), one O(18), one O(2), one O(28), and one O(3) atom to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(5)O6 octahedra,  a cornercorner with one Y(10)O7 pentagonal bipyramid,  a cornercorner with one Y(11)O7 pentagonal bipyramid,  a cornercorner with one Y(8)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O8 hexagonal bipyramid,  an edgeedge with one Y(10)O7 pentagonal bipyramid,  an edgeedge with one Y(8)O7 pentagonal bipyramid, and  an edgeedge with one Y(9)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 37-64°. The Ta(2)-O(1) bond length is 2.04 Å. The Ta(2)-O(10) bond length is 2.01 Å. The Ta(2)-O(18) bond length is 2.02 Å. The Ta(2)-O(2) bond length is 2.07 Å. The Ta(2)-O(28) bond length is 1.96 Å. The Ta(2)-O(3) bond length is 2.10 Å. In the third Ta site, Ta(3) is bonded to one O(12), one O(14), one O(15), one O(16), one O(21), and one O(22) atom to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra,  a cornercorner with one Y(1)O7 pentagonal bipyramid,  a cornercorner with one Y(3)O7 pentagonal bipyramid,  a cornercorner with one Y(9)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O8 hexagonal bipyramid,  an edgeedge with one Y(1)O7 pentagonal bipyramid,  an edgeedge with one Y(11)O7 pentagonal bipyramid, and  an edgeedge with one Y(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 38-64°. The Ta(3)-O(12) bond length is 2.13 Å. The Ta(3)-O(14) bond length is 2.02 Å. The Ta(3)-O(15) bond length is 2.07 Å. The Ta(3)-O(16) bond length is 2.04 Å. The Ta(3)-O(21) bond length is 2.01 Å. The Ta(3)-O(22) bond length is 1.96 Å. In the fourth Ta site, Ta(4) is bonded to one O(11), one O(15), one O(16), one O(17), one O(20), and one O(9) atom to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra,  a cornercorner with one Y(1)O7 pentagonal bipyramid,  a cornercorner with one Y(3)O7 pentagonal bipyramid,  a cornercorner with one Y(9)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O8 hexagonal bipyramid,  an edgeedge with one Y(1)O7 pentagonal bipyramid,  an edgeedge with one Y(11)O7 pentagonal bipyramid, and  an edgeedge with one Y(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 38-64°. The Ta(4)-O(11) bond length is 2.11 Å. The Ta(4)-O(15) bond length is 2.07 Å. The Ta(4)-O(16) bond length is 2.04 Å. The Ta(4)-O(17) bond length is 2.01 Å. The Ta(4)-O(20) bond length is 1.97 Å. The Ta(4)-O(9) bond length is 2.02 Å. In the fifth Ta site, Ta(5) is bonded to one O(1), one O(13), one O(19), one O(2), one O(27), and one O(4) atom to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra,  a cornercorner with one Y(10)O7 pentagonal bipyramid,  a cornercorner with one Y(11)O7 pentagonal bipyramid,  a cornercorner with one Y(8)O7 pentagonal bipyramid,  an edgeedge with one Y(2)O8 hexagonal bipyramid,  an edgeedge with one Y(10)O7 pentagonal bipyramid,  an edgeedge with one Y(8)O7 pentagonal bipyramid, and  an edgeedge with one Y(9)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 37-64°. The Ta(5)-O(1) bond length is 2.04 Å. The Ta(5)-O(13) bond length is 2.02 Å. The Ta(5)-O(19) bond length is 2.01 Å. The Ta(5)-O(2) bond length is 2.06 Å. The Ta(5)-O(27) bond length is 1.96 Å. The Ta(5)-O(4) bond length is 2.12 Å. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded to one Y(10), one Y(2), one Ta(2), and one Ta(5) atom to form OY2Ta2 tetrahedra that share  a cornercorner with one O(16)Y2Ta2 tetrahedra,  a cornercorner with one O(27)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(10)Y3Ta tetrahedra, corners with two equivalent O(13)Y3Ta tetrahedra, corners with two equivalent O(2)Y2Ta2 trigonal pyramids,  an edgeedge with one O(18)Y3Ta tetrahedra,  an edgeedge with one O(19)Y3Ta tetrahedra, and  an edgeedge with one O(8)Y4 tetrahedra. In the second O site, O(2) is bonded to one Y(8), one Y(9), one Ta(2), and one Ta(5) atom to form distorted OY2Ta2 trigonal pyramids that share  a cornercorner with one O(20)Y3Ta tetrahedra,  a cornercorner with one O(22)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra, corners with two equivalent O(1)Y2Ta2 tetrahedra, corners with two equivalent O(18)Y3Ta tetrahedra, corners with two equivalent O(19)Y3Ta tetrahedra,  an edgeedge with one O(10)Y3Ta tetrahedra,  an edgeedge with one O(13)Y3Ta tetrahedra,  an edgeedge with one O(27)Y3Ta tetrahedra, and  an edgeedge with one O(24)Y4 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Y(2), one Y(5), one Ta(1), and one Ta(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Y(2), one Y(6), one Ta(1), and one Ta(5) atom. In the fifth O site, O(5) is bonded to one Y(11), one Y(3), one Y(4), and one Y(7) atom to form OY4 tetrahedra that share  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(18)Y3Ta tetrahedra,  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(20)Y3Ta tetrahedra, corners with two equivalent O(22)Y3Ta tetrahedra, corners with two equivalent O(24)Y4 tetrahedra, corners with two equivalent O(6)Y4 tetrahedra,  an edgeedge with one O(14)Y3Ta tetrahedra,  an edgeedge with one O(27)Y3Ta tetrahedra,  an edgeedge with one O(9)Y3Ta tetrahedra,  an edgeedge with one O(25)Y4 tetrahedra, and  an edgeedge with one O(15)Y2Ta2 trigonal pyramid. In the sixth O site, O(6) is bonded to one Y(1), one Y(4), one Y(7), and one Y(9) atom to form OY4 tetrahedra that share  a cornercorner with one O(16)Y2Ta2 tetrahedra,  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(18)Y3Ta tetrahedra,  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(24)Y4 tetrahedra, corners with two equivalent O(20)Y3Ta tetrahedra, corners with two equivalent O(22)Y3Ta tetrahedra, corners with two equivalent O(25)Y4 tetrahedra, corners with two equivalent O(5)Y4 tetrahedra,  a cornercorner with one O(2)Y2Ta2 trigonal pyramid,  an edgeedge with one O(14)Y3Ta tetrahedra,  an edgeedge with one O(27)Y3Ta tetrahedra,  an edgeedge with one O(9)Y3Ta tetrahedra, and  an edgeedge with one O(24)Y4 tetrahedra. In the seventh O site, O(7) is bonded to one Y(5), one Y(6), one Y(8), and one Ta(1) atom to form OY3Ta tetrahedra that share  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(18)Y3Ta tetrahedra,  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(24)Y4 tetrahedra, corners with two equivalent O(23)Y4 tetrahedra, corners with two equivalent O(8)Y4 tetrahedra,  a cornercorner with one O(2)Y2Ta2 trigonal pyramid,  an edgeedge with one O(10)Y3Ta tetrahedra,  an edgeedge with one O(13)Y3Ta tetrahedra, and  an edgeedge with one O(26)Y3Ta tetrahedra. In the eighth O site, O(8) is bonded to one Y(10), one Y(2), one Y(5), and one Y(6) atom to form OY4 tetrahedra that share  a cornercorner with one O(16)Y2Ta2 tetrahedra,  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(18)Y3Ta tetrahedra,  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(26)Y3Ta tetrahedra, corners with two equivalent O(7)Y3Ta tetrahedra,  an edgeedge with one O(1)Y2Ta2 tetrahedra,  an edgeedge with one O(10)Y3Ta tetrahedra,  an edgeedge with one O(13)Y3Ta tetrahedra, and  an edgeedge with one O(23)Y4 tetrahedra. In the ninth O site, O(9) is bonded to one Y(1), one Y(3), one Y(7), and one Ta(4) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(18)Y3Ta tetrahedra,  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(24)Y4 tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(14)Y3Ta tetrahedra, corners with two equivalent O(21)Y3Ta tetrahedra, corners with two equivalent O(15)Y2Ta2 trigonal pyramids,  an edgeedge with one O(16)Y2Ta2 tetrahedra,  an edgeedge with one O(17)Y3Ta tetrahedra,  an edgeedge with one O(20)Y3Ta tetrahedra,  an edgeedge with one O(5)Y4 tetrahedra, and  an edgeedge with one O(6)Y4 tetrahedra. In the tenth O site, O(10) is bonded to one Y(10), one Y(5), one Y(8), and one Ta(2) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(18)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(24)Y4 tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(1)Y2Ta2 tetrahedra, corners with two equivalent O(13)Y3Ta tetrahedra, corners with two equivalent O(19)Y3Ta tetrahedra,  an edgeedge with one O(18)Y3Ta tetrahedra,  an edgeedge with one O(7)Y3Ta tetrahedra,  an edgeedge with one O(8)Y4 tetrahedra, and  an edgeedge with one O(2)Y2Ta2 trigonal pyramid. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Y(2), one Y(6), one Ta(1), and one Ta(4) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Y(2), one Y(5), one Ta(1), and one Ta(3) atom. In the thirteenth O site, O(13) is bonded to one Y(10), one Y(6), one Y(8), and one Ta(5) atom to form OY3Ta tetrahedra that share  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(27)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(24)Y4 tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(1)Y2Ta2 tetrahedra, corners with two equivalent O(10)Y3Ta tetrahedra, corners with two equivalent O(18)Y3Ta tetrahedra,  an edgeedge with one O(19)Y3Ta tetrahedra,  an edgeedge with one O(7)Y3Ta tetrahedra,  an edgeedge with one O(8)Y4 tetrahedra, and  an edgeedge with one O(2)Y2Ta2 trigonal pyramid. In the fourteenth O site, O(14) is bonded to one Y(1), one Y(3), one Y(4), and one Ta(3) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(27)Y3Ta tetrahedra,  a cornercorner with one O(23)Y4 tetrahedra,  a cornercorner with one O(24)Y4 tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(17)Y3Ta tetrahedra, corners with two equivalent O(9)Y3Ta tetrahedra, corners with two equivalent O(15)Y2Ta2 trigonal pyramids,  an edgeedge with one O(16)Y2Ta2 tetrahedra,  an edgeedge with one O(21)Y3Ta tetrahedra,  an edgeedge with one O(22)Y3Ta tetrahedra,  an edgeedge with one O(5)Y4 tetrahedra, and  an edgeedge with one O(6)Y4 tetrahedra. In the fifteenth O site, O(15) is bonded to one Y(11), one Y(3), one Ta(3), and one Ta(4) atom to form distorted OY2Ta2 trigonal pyramids that share  a cornercorner with one O(26)Y3Ta tetrahedra,  a cornercorner with one O(27)Y3Ta tetrahedra,  a cornercorner with one O(25)Y4 tetrahedra, corners with two equivalent O(16)Y2Ta2 tetrahedra, corners with two equivalent O(14)Y3Ta tetrahedra, corners with two equivalent O(9)Y3Ta tetrahedra,  an edgeedge with one O(17)Y3Ta tetrahedra,  an edgeedge with one O(20)Y3Ta tetrahedra,  an edgeedge with one O(21)Y3Ta tetrahedra,  an edgeedge with one O(22)Y3Ta tetrahedra, and  an edgeedge with one O(5)Y4 tetrahedra. In the sixteenth O site, O(16) is bonded to one Y(1), one Y(2), one Ta(3), and one Ta(4) atom to form OY2Ta2 tetrahedra that share  a cornercorner with one O(1)Y2Ta2 tetrahedra,  a cornercorner with one O(20)Y3Ta tetrahedra,  a cornercorner with one O(22)Y3Ta tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(17)Y3Ta tetrahedra, corners with two equivalent O(21)Y3Ta tetrahedra, corners with two equivalent O(15)Y2Ta2 trigonal pyramids,  an edgeedge with one O(14)Y3Ta tetrahedra,  an edgeedge with one O(9)Y3Ta tetrahedra, and  an edgeedge with one O(23)Y4 tetrahedra. In the seventeenth O site, O(17) is bonded to one Y(1), one Y(3), one Y(6), and one Ta(4) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(20)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(9)Y3Ta tetrahedra,  a cornercorner with one O(5)Y4 tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(16)Y2Ta2 tetrahedra, corners with two equivalent O(14)Y3Ta tetrahedra, corners with two equivalent O(21)Y3Ta tetrahedra,  an edgeedge with one O(26)Y3Ta tetrahedra,  an edgeedge with one O(9)Y3Ta tetrahedra,  an edgeedge with one O(23)Y4 tetrahedra, and  an edgeedge with one O(15)Y2Ta2 trigonal pyramid. In the eighteenth O site, O(18) is bonded to one Y(10), one Y(7), one Y(8), and one Ta(2) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(10)Y3Ta tetrahedra,  a cornercorner with one O(20)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(9)Y3Ta tetrahedra,  a cornercorner with one O(5)Y4 tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(13)Y3Ta tetrahedra, corners with two equivalent O(19)Y3Ta tetrahedra, corners with two equivalent O(2)Y2Ta2 trigonal pyramids,  an edgeedge with one O(1)Y2Ta2 tetrahedra,  an edgeedge with one O(10)Y3Ta tetrahedra,  an edgeedge with one O(24)Y4 tetrahedra, and  an edgeedge with one O(25)Y4 tetrahedra. In the nineteenth O site, O(19) is bonded to one Y(10), one Y(4), one Y(8), and one Ta(5) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(22)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(5)Y4 tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(10)Y3Ta tetrahedra, corners with two equivalent O(18)Y3Ta tetrahedra, corners with two equivalent O(2)Y2Ta2 trigonal pyramids,  an edgeedge with one O(1)Y2Ta2 tetrahedra,  an edgeedge with one O(13)Y3Ta tetrahedra,  an edgeedge with one O(27)Y3Ta tetrahedra,  an edgeedge with one O(24)Y4 tetrahedra, and  an edgeedge with one O(25)Y4 tetrahedra. In the twentieth O site, O(20) is bonded to one Y(11), one Y(7), one Y(9), and one Ta(4) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(16)Y2Ta2 tetrahedra,  a cornercorner with one O(17)Y3Ta tetrahedra,  a cornercorner with one O(18)Y3Ta tetrahedra, corners with two equivalent O(22)Y3Ta tetrahedra, corners with two equivalent O(27)Y3Ta tetrahedra, corners with two equivalent O(5)Y4 tetrahedra, corners with two equivalent O(6)Y4 tetrahedra,  a cornercorner with one O(2)Y2Ta2 trigonal pyramid,  an edgeedge with one O(9)Y3Ta tetrahedra,  an edgeedge with one O(24)Y4 tetrahedra,  an edgeedge with one O(25)Y4 tetrahedra, and  an edgeedge with one O(15)Y2Ta2 trigonal pyramid. In the twenty-first O site, O(21) is bonded to one Y(1), one Y(3), one Y(5), and one Ta(3) atom to form OY3Ta tetrahedra that share  a cornercorner with one O(10)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(22)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(5)Y4 tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(16)Y2Ta2 tetrahedra, corners with two equivalent O(17)Y3Ta tetrahedra, corners with two equivalent O(9)Y3Ta tetrahedra,  an edgeedge with one O(14)Y3Ta tetrahedra,  an edgeedge with one O(26)Y3Ta tetrahedra,  an edgeedge with one O(23)Y4 tetrahedra, and  an edgeedge with one O(15)Y2Ta2 trigonal pyramid. In the twenty-second O site, O(22) is bonded to one Y(11), one Y(4), one Y(9), and one Ta(3) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(16)Y2Ta2 tetrahedra,  a cornercorner with one O(19)Y3Ta tetrahedra,  a cornercorner with one O(21)Y3Ta tetrahedra,  a cornercorner with one O(27)Y3Ta tetrahedra, corners with two equivalent O(20)Y3Ta tetrahedra, corners with two equivalent O(5)Y4 tetrahedra, corners with two equivalent O(6)Y4 tetrahedra,  a cornercorner with one O(2)Y2Ta2 trigonal pyramid,  an edgeedge with one O(14)Y3Ta tetrahedra,  an edgeedge with one O(27)Y3Ta tetrahedra,  an edgeedge with one O(24)Y4 tetrahedra,  an edgeedge with one O(25)Y4 tetrahedra, and  an edgeedge with one O(15)Y2Ta2 trigonal pyramid. In the twenty-third O site, O(23) is bonded to one Y(1), one Y(2), one Y(5), and one Y(6) atom to form OY4 tetrahedra that share  a cornercorner with one O(1)Y2Ta2 tetrahedra,  a cornercorner with one O(10)Y3Ta tetrahedra,  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(9)Y3Ta tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(26)Y3Ta tetrahedra, corners with two equivalent O(7)Y3Ta tetrahedra,  an edgeedge with one O(16)Y2Ta2 tetrahedra,  an edgeedge with one O(17)Y3Ta tetrahedra,  an edgeedge with one O(21)Y3Ta tetrahedra, and  an edgeedge with one O(8)Y4 tetrahedra. In the twenty-fourth O site, O(24) is bonded to one Y(4), one Y(7), one Y(8), and one Y(9) atom to form OY4 tetrahedra that share  a cornercorner with one O(10)Y3Ta tetrahedra,  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(9)Y3Ta tetrahedra,  a cornercorner with one O(6)Y4 tetrahedra, corners with two equivalent O(27)Y3Ta tetrahedra, corners with two equivalent O(25)Y4 tetrahedra, corners with two equivalent O(5)Y4 tetrahedra,  an edgeedge with one O(18)Y3Ta tetrahedra,  an edgeedge with one O(19)Y3Ta tetrahedra,  an edgeedge with one O(20)Y3Ta tetrahedra,  an edgeedge with one O(22)Y3Ta tetrahedra,  an edgeedge with one O(6)Y4 tetrahedra, and  an edgeedge with one O(2)Y2Ta2 trigonal pyramid. In the twenty-fifth O site, O(25) is bonded to one Y(10), one Y(11), one Y(4), and one Y(7) atom to form OY4 tetrahedra that share  a cornercorner with one O(1)Y2Ta2 tetrahedra,  a cornercorner with one O(10)Y3Ta tetrahedra,  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(9)Y3Ta tetrahedra,  a cornercorner with one O(5)Y4 tetrahedra,  a cornercorner with one O(8)Y4 tetrahedra, corners with two equivalent O(27)Y3Ta tetrahedra, corners with two equivalent O(24)Y4 tetrahedra, corners with two equivalent O(6)Y4 tetrahedra,  a cornercorner with one O(15)Y2Ta2 trigonal pyramid,  an edgeedge with one O(18)Y3Ta tetrahedra,  an edgeedge with one O(19)Y3Ta tetrahedra,  an edgeedge with one O(20)Y3Ta tetrahedra,  an edgeedge with one O(22)Y3Ta tetrahedra, and  an edgeedge with one O(5)Y4 tetrahedra. In the twenty-sixth O site, O(26) is bonded to one Y(3), one Y(5), one Y(6), and one Ta(1) atom to form OY3Ta tetrahedra that share  a cornercorner with one O(10)Y3Ta tetrahedra,  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(7)Y3Ta tetrahedra,  a cornercorner with one O(9)Y3Ta tetrahedra,  a cornercorner with one O(5)Y4 tetrahedra, corners with two equivalent O(23)Y4 tetrahedra, corners with two equivalent O(8)Y4 tetrahedra,  a cornercorner with one O(15)Y2Ta2 trigonal pyramid,  an edgeedge with one O(17)Y3Ta tetrahedra,  an edgeedge with one O(21)Y3Ta tetrahedra, and  an edgeedge with one O(7)Y3Ta tetrahedra. In the twenty-seventh O site, O(27) is bonded to one Y(11), one Y(4), one Y(9), and one Ta(5) atom to form distorted OY3Ta tetrahedra that share  a cornercorner with one O(1)Y2Ta2 tetrahedra,  a cornercorner with one O(13)Y3Ta tetrahedra,  a cornercorner with one O(14)Y3Ta tetrahedra,  a cornercorner with one O(22)Y3Ta tetrahedra, corners with two equivalent O(20)Y3Ta tetrahedra, corners with two equivalent O(24)Y4 tetrahedra, corners with two equivalent O(25)Y4 tetrahedra,  a cornercorner with one O(15)Y2Ta2 trigonal pyramid,  an edgeedge with one O(19)Y3Ta tetrahedra,  an edgeedge with one O(22)Y3Ta tetrahedra,  an edgeedge with one O(5)Y4 tetrahedra,  an edgeedge with one O(6)Y4 tetrahedra, and  an edgeedge with one O(2)Y2Ta2 trigonal pyramid. In the twenty-eighth O site, O(28) is bonded in a 4-coordinate geometry to one Y(11), one Y(7), one Y(9), and one Ta(2) atom.