Na3Cu2SbO6 crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra, edges with two equivalent Sb(1)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with three equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles are 12°. In the second Na site, Na(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra, edges with two equivalent Sb(1)O6 octahedra, and edges with six equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles are 13°. Cu(1) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(2) atoms. Sb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form SbO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, and edges with four equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-13°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), two equivalent Na(1), one Cu(1), and one Sb(1) atom to form a mixture of distorted corner and edge-sharing ONa3CuSb square pyramids. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(2), two equivalent Na(1), two equivalent Cu(1), and one Sb(1) atom.
Na3Cu2SbO6 crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra, edges with two equivalent Sb(1)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with three equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles are 12°. Both Na(1)-O(2) bond lengths are 2.46 Å. There are two shorter (2.35 Å) and two longer (2.36 Å) Na(1)-O(1) bond lengths. In the second Na site, Na(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra, edges with two equivalent Sb(1)O6 octahedra, and edges with six equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles are 13°. Both Na(2)-O(2) bond lengths are 2.90 Å. All Na(2)-O(1) bond lengths are 2.36 Å. Cu(1) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Cu(1)-O(1) bond lengths are 2.03 Å. Both Cu(1)-O(2) bond lengths are 2.02 Å. Sb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form SbO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, and edges with four equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-13°. Both Sb(1)-O(2) bond lengths are 2.12 Å. All Sb(1)-O(1) bond lengths are 2.00 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), two equivalent Na(1), one Cu(1), and one Sb(1) atom to form a mixture of distorted corner and edge-sharing ONa3CuSb square pyramids. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(2), two equivalent Na(1), two equivalent Cu(1), and one Sb(1) atom.