Na3SrTa4O12 is Orthorhombic Perovskite-derived structured and crystallizes in the monoclinic Pm space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(5), one O(6), two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. In the second Na site, Na(2) is bonded in a 9-coordinate geometry to one O(7), two equivalent O(1), two equivalent O(2), two equivalent O(4), and two equivalent O(8) atoms. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(7), one O(8), two equivalent O(1), and two equivalent O(3) atoms. Sr(1) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(7) atom to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 16-24°. In the second Ta site, Ta(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(8) atom to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 16-24°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Ta(1), and one Ta(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Na(2), one Sr(1), one Ta(1), and one Ta(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(1), one Na(3), one Sr(1), one Ta(1), and one Ta(2) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Na(1), one Na(2), one Sr(1), one Ta(1), and one Ta(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Sr(1), and two equivalent Ta(1) atoms. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Sr(1), and two equivalent Ta(2) atoms. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), and two equivalent Ta(1) atoms. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(3), two equivalent Na(2), and two equivalent Ta(2) atoms.
Na3SrTa4O12 is Orthorhombic Perovskite-derived structured and crystallizes in the monoclinic Pm space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(5), one O(6), two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. The Na(1)-O(5) bond length is 2.51 Å. The Na(1)-O(6) bond length is 2.48 Å. Both Na(1)-O(1) bond lengths are 2.79 Å. Both Na(1)-O(3) bond lengths are 2.46 Å. Both Na(1)-O(4) bond lengths are 2.91 Å. In the second Na site, Na(2) is bonded in a 9-coordinate geometry to one O(7), two equivalent O(1), two equivalent O(2), two equivalent O(4), and two equivalent O(8) atoms. The Na(2)-O(7) bond length is 2.54 Å. Both Na(2)-O(1) bond lengths are 2.77 Å. Both Na(2)-O(2) bond lengths are 2.55 Å. Both Na(2)-O(4) bond lengths are 2.61 Å. There is one shorter (2.72 Å) and one longer (2.87 Å) Na(2)-O(8) bond length. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(7), one O(8), two equivalent O(1), and two equivalent O(3) atoms. The Na(3)-O(7) bond length is 2.50 Å. The Na(3)-O(8) bond length is 2.47 Å. Both Na(3)-O(1) bond lengths are 2.46 Å. Both Na(3)-O(3) bond lengths are 2.83 Å. Sr(1) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. Both Sr(1)-O(2) bond lengths are 2.63 Å. Both Sr(1)-O(3) bond lengths are 2.71 Å. Both Sr(1)-O(4) bond lengths are 2.57 Å. There is one shorter (2.61 Å) and one longer (2.96 Å) Sr(1)-O(5) bond length. There is one shorter (2.75 Å) and one longer (2.85 Å) Sr(1)-O(6) bond length. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(7) atom to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 16-24°. The Ta(1)-O(1) bond length is 1.99 Å. The Ta(1)-O(2) bond length is 1.99 Å. The Ta(1)-O(3) bond length is 2.00 Å. The Ta(1)-O(4) bond length is 2.00 Å. The Ta(1)-O(5) bond length is 2.02 Å. The Ta(1)-O(7) bond length is 1.97 Å. In the second Ta site, Ta(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(8) atom to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 16-24°. The Ta(2)-O(1) bond length is 1.99 Å. The Ta(2)-O(2) bond length is 2.00 Å. The Ta(2)-O(3) bond length is 2.00 Å. The Ta(2)-O(4) bond length is 1.99 Å. The Ta(2)-O(6) bond length is 2.02 Å. The Ta(2)-O(8) bond length is 1.97 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Ta(1), and one Ta(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Na(2), one Sr(1), one Ta(1), and one Ta(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(1), one Na(3), one Sr(1), one Ta(1), and one Ta(2) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Na(1), one Na(2), one Sr(1), one Ta(1), and one Ta(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Sr(1), and two equivalent Ta(1) atoms. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Sr(1), and two equivalent Ta(2) atoms. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), and two equivalent Ta(1) atoms. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(3), two equivalent Na(2), and two equivalent Ta(2) atoms.