NaCa2Ta3O10 crystallizes in the tetragonal I-4m2 space group. Na(1) is bonded to four equivalent O(1) atoms to form corner-sharing NaO4 tetrahedra. Ca(1) is bonded in a 12-coordinate geometry to two equivalent O(3), two equivalent O(4), four equivalent O(2), and four equivalent O(5) atoms. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Ta site, Ta(2) is bonded to two equivalent O(2) and four equivalent O(5) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra are not tilted. There are five inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Na(1) and one Ta(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Ca(1), one Ta(1), and one Ta(2) atom. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1) and two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1) and two equivalent Ta(1) atoms. In the fifth O site, O(5) is bonded in a linear geometry to four equivalent Ca(1) and two equivalent Ta(2) atoms.
NaCa2Ta3O10 crystallizes in the tetragonal I-4m2 space group. Na(1) is bonded to four equivalent O(1) atoms to form corner-sharing NaO4 tetrahedra. All Na(1)-O(1) bond lengths are 2.35 Å. Ca(1) is bonded in a 12-coordinate geometry to two equivalent O(3), two equivalent O(4), four equivalent O(2), and four equivalent O(5) atoms. Both Ca(1)-O(3) bond lengths are 2.52 Å. Both Ca(1)-O(4) bond lengths are 2.51 Å. All Ca(1)-O(2) bond lengths are 2.81 Å. All Ca(1)-O(5) bond lengths are 3.03 Å. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms. The Ta(1)-O(1) bond length is 1.80 Å. The Ta(1)-O(2) bond length is 2.31 Å. Both Ta(1)-O(3) bond lengths are 2.01 Å. Both Ta(1)-O(4) bond lengths are 2.02 Å. In the second Ta site, Ta(2) is bonded to two equivalent O(2) and four equivalent O(5) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra are not tilted. Both Ta(2)-O(2) bond lengths are 1.97 Å. All Ta(2)-O(5) bond lengths are 1.97 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Na(1) and one Ta(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Ca(1), one Ta(1), and one Ta(2) atom. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1) and two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1) and two equivalent Ta(1) atoms. In the fifth O site, O(5) is bonded in a linear geometry to four equivalent Ca(1) and two equivalent Ta(2) atoms.