Na5IO6 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are three 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 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 I(1)O6 octahedra, and edges with four equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 18-22°. In the second Na site, Na(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NaO6 octahedra that share corners with two equivalent I(1)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent I(1)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, edges with three equivalent Na(3)O6 octahedra, and edges with four equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-22°. In the third Na site, Na(3) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with two equivalent I(1)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent I(1)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with six equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-18°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(3), two equivalent Na(1), two equivalent Na(2), and one I(1) atom to form a mixture of distorted corner and edge-sharing ONa5I octahedra. The corner-sharing octahedral tilt angles range from 0-16°. In the second O site, O(2) is bonded to one Na(3), two equivalent Na(1), two equivalent Na(2), and one I(1) atom to form a mixture of distorted corner and edge-sharing ONa5I octahedra. The corner-sharing octahedral tilt angles range from 0-15°. I(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form IO6 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 four equivalent Na(2)O6 octahedra, and edges with six equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°.
Na5IO6 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are three 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 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 I(1)O6 octahedra, and edges with four equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 18-22°. Both Na(1)-O(2) bond lengths are 2.32 Å. There are two shorter (2.33 Å) and two longer (2.40 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 NaO6 octahedra that share corners with two equivalent I(1)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent I(1)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, edges with three equivalent Na(3)O6 octahedra, and edges with four equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-22°. Both Na(2)-O(2) bond lengths are 2.35 Å. There are two shorter (2.33 Å) and two longer (2.62 Å) Na(2)-O(1) bond lengths. In the third Na site, Na(3) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with two equivalent I(1)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent I(1)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with six equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-18°. Both Na(3)-O(2) bond lengths are 2.78 Å. All Na(3)-O(1) bond lengths are 2.29 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(3), two equivalent Na(1), two equivalent Na(2), and one I(1) atom to form a mixture of distorted corner and edge-sharing ONa5I octahedra. The corner-sharing octahedral tilt angles range from 0-16°. The O(1)-I(1) bond length is 1.91 Å. In the second O site, O(2) is bonded to one Na(3), two equivalent Na(1), two equivalent Na(2), and one I(1) atom to form a mixture of distorted corner and edge-sharing ONa5I octahedra. The corner-sharing octahedral tilt angles range from 0-15°. The O(2)-I(1) bond length is 1.88 Å. I(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form IO6 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 four equivalent Na(2)O6 octahedra, and edges with six equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°.