NaTaO3 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(10), one O(12), one O(16), one O(2), and one O(24) atom to form NaO5 trigonal bipyramids that share  a cornercorner with one Ta(5)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra,  a cornercorner with one Ta(2)O5 trigonal bipyramid, corners with two equivalent Ta(8)O5 trigonal bipyramids, and  an edgeedge with one Ta(6)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 49-60°. In the second Na site, Na(2) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(11), one O(16), and one O(17) atom. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(12), one O(17), one O(3), and one O(5) atom. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(11), one O(4), one O(5), one O(7), and one O(8) atom. In the fifth Na site, Na(5) is bonded in a 7-coordinate geometry to one O(13), one O(20), one O(21), one O(23), one O(24), one O(6), and one O(9) atom. In the sixth Na site, Na(6) is bonded in a 5-coordinate geometry to one O(10), one O(12), one O(13), one O(16), and one O(19) atom. In the seventh Na site, Na(7) is bonded to one O(13), one O(14), one O(15), one O(18), one O(19), one O(20), one O(21), and one O(9) atom to form distorted NaO8 hexagonal bipyramids that share corners with two equivalent Ta(6)O4 trigonal pyramids,  an edgeedge with one Ta(3)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra,  an edgeedge with one Ta(7)O6 octahedra, edges with two equivalent Ta(5)O6 octahedra, and  an edgeedge with one Ta(8)O5 trigonal bipyramid. In the eighth Na site, Na(8) is bonded in a 7-coordinate geometry to one O(1), one O(14), one O(21), one O(22), one O(23), one O(3), and one O(8) atom. There are eight inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(17), one O(22), one O(23), one O(3), and one O(6) atom to form TaO6 octahedra that share  a cornercorner with one Ta(5)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, corners with two equivalent Ta(7)O6 octahedra, and  a cornercorner with one Ta(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 29-45°. In the second Ta site, Ta(2) is bonded to one O(11), one O(17), one O(2), one O(5), and one O(7) atom to form TaO5 trigonal 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,  a cornercorner with one Ta(7)O6 octahedra,  a cornercorner with one Na(1)O5 trigonal bipyramid, and  a cornercorner with one Ta(8)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 36-53°. In the third Ta site, Ta(3) is bonded to one O(14), one O(18), one O(22), one O(3), one O(5), and one O(8) atom to form TaO6 octahedra that share  a cornercorner with one Ta(5)O6 octahedra, corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(7)O6 octahedra,  a cornercorner with one Ta(2)O5 trigonal bipyramid, and  an edgeedge with one Na(7)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 29-45°. In the fourth Ta site, Ta(4) is bonded to one O(10), one O(12), one O(15), one O(19), one O(4), and one O(7) atom to form TaO6 octahedra that share  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(2)O5 trigonal bipyramid, corners with two equivalent Na(1)O5 trigonal bipyramids, corners with two equivalent Ta(8)O5 trigonal bipyramids,  a cornercorner with one Ta(6)O4 trigonal pyramid, and  an edgeedge with one Na(7)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles are 32°. In the fifth Ta site, Ta(5) is bonded to one O(15), one O(18), one O(20), one O(24), one O(6), and one O(9) atom to form TaO6 octahedra 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,  a cornercorner with one Ta(7)O6 octahedra,  a cornercorner with one Na(1)O5 trigonal bipyramid,  a cornercorner with one Ta(8)O5 trigonal bipyramid,  a cornercorner with one Ta(6)O4 trigonal pyramid, and edges with two equivalent Na(7)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 32-39°. In the sixth Ta site, Ta(6) is bonded to one O(10), one O(13), one O(21), and one O(24) atom to form distorted TaO4 trigonal pyramids that share corners with two equivalent Na(7)O8 hexagonal bipyramids,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra, and  an edgeedge with one Na(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 47-58°. In the seventh Ta site, Ta(7) is bonded to one O(1), one O(11), one O(14), one O(23), one O(8), and one O(9) atom to form TaO6 octahedra that share  a cornercorner with one Ta(5)O6 octahedra, corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra,  a cornercorner with one Ta(2)O5 trigonal bipyramid, and  an edgeedge with one Na(7)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 34-45°. In the eighth Ta site, Ta(8) is bonded to one O(16), one O(19), one O(2), one O(20), and one O(4) atom to form TaO5 trigonal bipyramids that share  a cornercorner with one Ta(5)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra,  a cornercorner with one Ta(2)O5 trigonal bipyramid, corners with two equivalent Na(1)O5 trigonal bipyramids, and  an edgeedge with one Na(7)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 38-44°. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), one Na(8), one Ta(1), and one Ta(7) atom to form distorted corner-sharing ONa2Ta2 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Na(1), one Ta(2), and one Ta(8) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(3), one Na(8), one Ta(1), and one Ta(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(4), one Ta(4), and one Ta(8) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Na(3), one Na(4), one Ta(2), and one Ta(3) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Na(5), one Ta(1), and one Ta(5) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(4), one Ta(2), and one Ta(4) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Na(4), one Na(8), one Ta(3), and one Ta(7) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Na(5), one Na(7), one Ta(5), and one Ta(7) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(6), one Ta(4), and one Ta(6) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Na(2), one Na(4), one Ta(2), and one Ta(7) atom. In the twelfth O site, O(12) is bonded to one Na(1), one Na(3), one Na(6), and one Ta(4) atom to form ONa3Ta tetrahedra that share corners with two equivalent O(16)Na3Ta tetrahedra and  an edgeedge with one O(19)Na2Ta2 trigonal pyramid. In the thirteenth O site, O(13) is bonded in a rectangular see-saw-like geometry to one Na(5), one Na(6), one Na(7), and one Ta(6) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Na(7), one Na(8), one Ta(3), and one Ta(7) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Na(7), one Ta(4), and one Ta(5) atom. In the sixteenth O site, O(16) is bonded to one Na(1), one Na(2), one Na(6), and one Ta(8) atom to form distorted ONa3Ta tetrahedra that share  a cornercorner with one O(1)Na2Ta2 tetrahedra, corners with two equivalent O(12)Na3Ta tetrahedra, and  an edgeedge with one O(19)Na2Ta2 trigonal pyramid. In the seventeenth O site, O(17) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), one Na(3), one Ta(1), and one Ta(2) atom. In the eighteenth O site, O(18) is bonded in a 2-coordinate geometry to one Na(7), one Ta(3), and one Ta(5) atom. In the nineteenth O site, O(19) is bonded to one Na(6), one Na(7), one Ta(4), and one Ta(8) atom to form distorted edge-sharing ONa2Ta2 trigonal pyramids. In the twentieth O site, O(20) is bonded in a 2-coordinate geometry to one Na(5), one Na(7), one Ta(5), and one Ta(8) atom. In the twenty-first O site, O(21) is bonded in a 3-coordinate geometry to one Na(5), one Na(7), one Na(8), and one Ta(6) atom. In the twenty-second O site, O(22) is bonded in a 3-coordinate geometry to one Na(8), one Ta(1), and one Ta(3) atom. In the twenty-third O site, O(23) is bonded in a 4-coordinate geometry to one Na(5), one Na(8), one Ta(1), and one Ta(7) atom. In the twenty-fourth O site, O(24) is bonded in a 4-coordinate geometry to one Na(1), one Na(5), one Ta(5), and one Ta(6) atom.
NaTaO3 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(10), one O(12), one O(16), one O(2), and one O(24) atom to form NaO5 trigonal bipyramids that share  a cornercorner with one Ta(5)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra,  a cornercorner with one Ta(2)O5 trigonal bipyramid, corners with two equivalent Ta(8)O5 trigonal bipyramids, and  an edgeedge with one Ta(6)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 49-60°. The Na(1)-O(10) bond length is 2.39 Å. The Na(1)-O(12) bond length is 2.30 Å. The Na(1)-O(16) bond length is 2.38 Å. The Na(1)-O(2) bond length is 2.52 Å. The Na(1)-O(24) bond length is 2.37 Å. In the second Na site, Na(2) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(11), one O(16), and one O(17) atom. The Na(2)-O(1) bond length is 2.29 Å. The Na(2)-O(11) bond length is 2.30 Å. The Na(2)-O(16) bond length is 2.26 Å. The Na(2)-O(17) bond length is 2.33 Å. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(12), one O(17), one O(3), and one O(5) atom. The Na(3)-O(12) bond length is 2.33 Å. The Na(3)-O(17) bond length is 2.51 Å. The Na(3)-O(3) bond length is 2.36 Å. The Na(3)-O(5) bond length is 2.45 Å. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(11), one O(4), one O(5), one O(7), and one O(8) atom. The Na(4)-O(11) bond length is 2.70 Å. The Na(4)-O(4) bond length is 2.57 Å. The Na(4)-O(5) bond length is 2.61 Å. The Na(4)-O(7) bond length is 2.50 Å. The Na(4)-O(8) bond length is 2.49 Å. In the fifth Na site, Na(5) is bonded in a 7-coordinate geometry to one O(13), one O(20), one O(21), one O(23), one O(24), one O(6), and one O(9) atom. The Na(5)-O(13) bond length is 2.35 Å. The Na(5)-O(20) bond length is 3.04 Å. The Na(5)-O(21) bond length is 2.99 Å. The Na(5)-O(23) bond length is 2.52 Å. The Na(5)-O(24) bond length is 2.86 Å. The Na(5)-O(6) bond length is 2.49 Å. The Na(5)-O(9) bond length is 2.54 Å. In the sixth Na site, Na(6) is bonded in a 5-coordinate geometry to one O(10), one O(12), one O(13), one O(16), and one O(19) atom. The Na(6)-O(10) bond length is 2.66 Å. The Na(6)-O(12) bond length is 2.52 Å. The Na(6)-O(13) bond length is 2.39 Å. The Na(6)-O(16) bond length is 2.60 Å. The Na(6)-O(19) bond length is 2.56 Å. In the seventh Na site, Na(7) is bonded to one O(13), one O(14), one O(15), one O(18), one O(19), one O(20), one O(21), and one O(9) atom to form distorted NaO8 hexagonal bipyramids that share corners with two equivalent Ta(6)O4 trigonal pyramids,  an edgeedge with one Ta(3)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra,  an edgeedge with one Ta(7)O6 octahedra, edges with two equivalent Ta(5)O6 octahedra, and  an edgeedge with one Ta(8)O5 trigonal bipyramid. The Na(7)-O(13) bond length is 2.45 Å. The Na(7)-O(14) bond length is 2.76 Å. The Na(7)-O(15) bond length is 2.67 Å. The Na(7)-O(18) bond length is 2.76 Å. The Na(7)-O(19) bond length is 2.70 Å. The Na(7)-O(20) bond length is 2.88 Å. The Na(7)-O(21) bond length is 2.43 Å. The Na(7)-O(9) bond length is 2.70 Å. In the eighth Na site, Na(8) is bonded in a 7-coordinate geometry to one O(1), one O(14), one O(21), one O(22), one O(23), one O(3), and one O(8) atom. The Na(8)-O(1) bond length is 2.63 Å. The Na(8)-O(14) bond length is 2.67 Å. The Na(8)-O(21) bond length is 2.20 Å. The Na(8)-O(22) bond length is 2.60 Å. The Na(8)-O(23) bond length is 2.87 Å. The Na(8)-O(3) bond length is 2.89 Å. The Na(8)-O(8) bond length is 2.93 Å. There are eight inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(17), one O(22), one O(23), one O(3), and one O(6) atom to form TaO6 octahedra that share  a cornercorner with one Ta(5)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, corners with two equivalent Ta(7)O6 octahedra, and  a cornercorner with one Ta(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 29-45°. The Ta(1)-O(1) bond length is 1.97 Å. The Ta(1)-O(17) bond length is 2.22 Å. The Ta(1)-O(22) bond length is 2.00 Å. The Ta(1)-O(23) bond length is 1.97 Å. The Ta(1)-O(3) bond length is 1.98 Å. The Ta(1)-O(6) bond length is 1.91 Å. In the second Ta site, Ta(2) is bonded to one O(11), one O(17), one O(2), one O(5), and one O(7) atom to form TaO5 trigonal 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,  a cornercorner with one Ta(7)O6 octahedra,  a cornercorner with one Na(1)O5 trigonal bipyramid, and  a cornercorner with one Ta(8)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 36-53°. The Ta(2)-O(11) bond length is 1.92 Å. The Ta(2)-O(17) bond length is 1.87 Å. The Ta(2)-O(2) bond length is 1.99 Å. The Ta(2)-O(5) bond length is 1.97 Å. The Ta(2)-O(7) bond length is 1.98 Å. In the third Ta site, Ta(3) is bonded to one O(14), one O(18), one O(22), one O(3), one O(5), and one O(8) atom to form TaO6 octahedra that share  a cornercorner with one Ta(5)O6 octahedra, corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(7)O6 octahedra,  a cornercorner with one Ta(2)O5 trigonal bipyramid, and  an edgeedge with one Na(7)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 29-45°. The Ta(3)-O(14) bond length is 1.97 Å. The Ta(3)-O(18) bond length is 1.94 Å. The Ta(3)-O(22) bond length is 1.96 Å. The Ta(3)-O(3) bond length is 2.06 Å. The Ta(3)-O(5) bond length is 2.15 Å. The Ta(3)-O(8) bond length is 2.01 Å. In the fourth Ta site, Ta(4) is bonded to one O(10), one O(12), one O(15), one O(19), one O(4), and one O(7) atom to form TaO6 octahedra that share  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(2)O5 trigonal bipyramid, corners with two equivalent Na(1)O5 trigonal bipyramids, corners with two equivalent Ta(8)O5 trigonal bipyramids,  a cornercorner with one Ta(6)O4 trigonal pyramid, and  an edgeedge with one Na(7)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles are 32°. The Ta(4)-O(10) bond length is 2.17 Å. The Ta(4)-O(12) bond length is 1.88 Å. The Ta(4)-O(15) bond length is 2.01 Å. The Ta(4)-O(19) bond length is 1.98 Å. The Ta(4)-O(4) bond length is 2.03 Å. The Ta(4)-O(7) bond length is 1.98 Å. In the fifth Ta site, Ta(5) is bonded to one O(15), one O(18), one O(20), one O(24), one O(6), and one O(9) atom to form TaO6 octahedra 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,  a cornercorner with one Ta(7)O6 octahedra,  a cornercorner with one Na(1)O5 trigonal bipyramid,  a cornercorner with one Ta(8)O5 trigonal bipyramid,  a cornercorner with one Ta(6)O4 trigonal pyramid, and edges with two equivalent Na(7)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 32-39°. The Ta(5)-O(15) bond length is 1.91 Å. The Ta(5)-O(18) bond length is 2.08 Å. The Ta(5)-O(20) bond length is 1.98 Å. The Ta(5)-O(24) bond length is 2.00 Å. The Ta(5)-O(6) bond length is 1.99 Å. The Ta(5)-O(9) bond length is 2.01 Å. In the sixth Ta site, Ta(6) is bonded to one O(10), one O(13), one O(21), and one O(24) atom to form distorted TaO4 trigonal pyramids that share corners with two equivalent Na(7)O8 hexagonal bipyramids,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra, and  an edgeedge with one Na(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 47-58°. The Ta(6)-O(10) bond length is 1.87 Å. The Ta(6)-O(13) bond length is 1.88 Å. The Ta(6)-O(21) bond length is 1.85 Å. The Ta(6)-O(24) bond length is 1.93 Å. In the seventh Ta site, Ta(7) is bonded to one O(1), one O(11), one O(14), one O(23), one O(8), and one O(9) atom to form TaO6 octahedra that share  a cornercorner with one Ta(5)O6 octahedra, corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra,  a cornercorner with one Ta(2)O5 trigonal bipyramid, and  an edgeedge with one Na(7)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 34-45°. The Ta(7)-O(1) bond length is 2.00 Å. The Ta(7)-O(11) bond length is 2.10 Å. The Ta(7)-O(14) bond length is 1.98 Å. The Ta(7)-O(23) bond length is 1.98 Å. The Ta(7)-O(8) bond length is 2.00 Å. The Ta(7)-O(9) bond length is 1.93 Å. In the eighth Ta site, Ta(8) is bonded to one O(16), one O(19), one O(2), one O(20), and one O(4) atom to form TaO5 trigonal bipyramids that share  a cornercorner with one Ta(5)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra,  a cornercorner with one Ta(2)O5 trigonal bipyramid, corners with two equivalent Na(1)O5 trigonal bipyramids, and  an edgeedge with one Na(7)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 38-44°. The Ta(8)-O(16) bond length is 1.85 Å. The Ta(8)-O(19) bond length is 1.97 Å. The Ta(8)-O(2) bond length is 1.97 Å. The Ta(8)-O(20) bond length is 1.96 Å. The Ta(8)-O(4) bond length is 1.98 Å. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), one Na(8), one Ta(1), and one Ta(7) atom to form distorted corner-sharing ONa2Ta2 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Na(1), one Ta(2), and one Ta(8) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(3), one Na(8), one Ta(1), and one Ta(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(4), one Ta(4), and one Ta(8) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Na(3), one Na(4), one Ta(2), and one Ta(3) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Na(5), one Ta(1), and one Ta(5) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(4), one Ta(2), and one Ta(4) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Na(4), one Na(8), one Ta(3), and one Ta(7) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Na(5), one Na(7), one Ta(5), and one Ta(7) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(6), one Ta(4), and one Ta(6) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Na(2), one Na(4), one Ta(2), and one Ta(7) atom. In the twelfth O site, O(12) is bonded to one Na(1), one Na(3), one Na(6), and one Ta(4) atom to form ONa3Ta tetrahedra that share corners with two equivalent O(16)Na3Ta tetrahedra and  an edgeedge with one O(19)Na2Ta2 trigonal pyramid. In the thirteenth O site, O(13) is bonded in a rectangular see-saw-like geometry to one Na(5), one Na(6), one Na(7), and one Ta(6) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Na(7), one Na(8), one Ta(3), and one Ta(7) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Na(7), one Ta(4), and one Ta(5) atom. In the sixteenth O site, O(16) is bonded to one Na(1), one Na(2), one Na(6), and one Ta(8) atom to form distorted ONa3Ta tetrahedra that share  a cornercorner with one O(1)Na2Ta2 tetrahedra, corners with two equivalent O(12)Na3Ta tetrahedra, and  an edgeedge with one O(19)Na2Ta2 trigonal pyramid. In the seventeenth O site, O(17) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), one Na(3), one Ta(1), and one Ta(2) atom. In the eighteenth O site, O(18) is bonded in a 2-coordinate geometry to one Na(7), one Ta(3), and one Ta(5) atom. In the nineteenth O site, O(19) is bonded to one Na(6), one Na(7), one Ta(4), and one Ta(8) atom to form distorted edge-sharing ONa2Ta2 trigonal pyramids. In the twentieth O site, O(20) is bonded in a 2-coordinate geometry to one Na(5), one Na(7), one Ta(5), and one Ta(8) atom. In the twenty-first O site, O(21) is bonded in a 3-coordinate geometry to one Na(5), one Na(7), one Na(8), and one Ta(6) atom. In the twenty-second O site, O(22) is bonded in a 3-coordinate geometry to one Na(8), one Ta(1), and one Ta(3) atom. In the twenty-third O site, O(23) is bonded in a 4-coordinate geometry to one Na(5), one Na(8), one Ta(1), and one Ta(7) atom. In the twenty-fourth O site, O(24) is bonded in a 4-coordinate geometry to one Na(1), one Na(5), one Ta(5), and one Ta(6) atom.