Na2TbO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with three equivalent Tb(1)O6 octahedra, edges with three equivalent Tb(2)O6 octahedra, and edges with four equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-10°. In the second Na site, Na(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Tb(1)O6 octahedra, corners with two equivalent Tb(2)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Tb(1)O6 octahedra, edges with two equivalent Tb(2)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with three equivalent Na(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-10°. In the third Na site, Na(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Tb(1)O6 octahedra, corners with two equivalent Tb(2)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Tb(1)O6 octahedra, edges with two equivalent Tb(2)O6 octahedra, and edges with six equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-9°. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TbO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, edges with three equivalent Tb(2)O6 octahedra, and edges with four equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-10°. In the second Tb site, Tb(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TbO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, edges with three equivalent Tb(1)O6 octahedra, and edges with four equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-10°. There are three inequivalent O sites. In the first O site, O(3) is bonded to one Na(1), one Na(3), two equivalent Na(2), one Tb(1), and one Tb(2) atom to form a mixture of corner and edge-sharing ONa4Tb2 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. In the second O site, O(1) is bonded to one Na(1), one Na(3), two equivalent Na(2), one Tb(1), and one Tb(2) atom to form a mixture of corner and edge-sharing ONa4Tb2 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the third O site, O(2) is bonded to one Na(1), one Na(3), two equivalent Na(2), one Tb(1), and one Tb(2) atom to form a mixture of corner and edge-sharing ONa4Tb2 octahedra. The corner-sharing octahedral tilt angles range from 0-10°.
Na2TbO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with three equivalent Tb(1)O6 octahedra, edges with three equivalent Tb(2)O6 octahedra, and edges with four equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-10°. Both Na(1)-O(1) bond lengths are 2.53 Å. Both Na(1)-O(2) bond lengths are 2.50 Å. Both Na(1)-O(3) bond lengths are 2.50 Å. In the second Na site, Na(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Tb(1)O6 octahedra, corners with two equivalent Tb(2)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Tb(1)O6 octahedra, edges with two equivalent Tb(2)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with three equivalent Na(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-10°. There is one shorter (2.52 Å) and one longer (2.53 Å) Na(2)-O(1) bond length. There is one shorter (2.43 Å) and one longer (2.63 Å) Na(2)-O(2) bond length. There is one shorter (2.44 Å) and one longer (2.62 Å) Na(2)-O(3) bond length. In the third Na site, Na(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Tb(1)O6 octahedra, corners with two equivalent Tb(2)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Tb(1)O6 octahedra, edges with two equivalent Tb(2)O6 octahedra, and edges with six equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-9°. Both Na(3)-O(1) bond lengths are 2.39 Å. Both Na(3)-O(2) bond lengths are 2.59 Å. Both Na(3)-O(3) bond lengths are 2.60 Å. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TbO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, edges with three equivalent Tb(2)O6 octahedra, and edges with four equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-10°. Both Tb(1)-O(1) bond lengths are 2.29 Å. Both Tb(1)-O(2) bond lengths are 2.28 Å. Both Tb(1)-O(3) bond lengths are 2.29 Å. In the second Tb site, Tb(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TbO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, edges with three equivalent Tb(1)O6 octahedra, and edges with four equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-10°. Both Tb(2)-O(1) bond lengths are 2.29 Å. Both Tb(2)-O(2) bond lengths are 2.28 Å. Both Tb(2)-O(3) bond lengths are 2.28 Å. There are three inequivalent O sites. In the first O site, O(3) is bonded to one Na(1), one Na(3), two equivalent Na(2), one Tb(1), and one Tb(2) atom to form a mixture of corner and edge-sharing ONa4Tb2 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. In the second O site, O(1) is bonded to one Na(1), one Na(3), two equivalent Na(2), one Tb(1), and one Tb(2) atom to form a mixture of corner and edge-sharing ONa4Tb2 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the third O site, O(2) is bonded to one Na(1), one Na(3), two equivalent Na(2), one Tb(1), and one Tb(2) atom to form a mixture of corner and edge-sharing ONa4Tb2 octahedra. The corner-sharing octahedral tilt angles range from 0-10°.