Na4C4Sb2SO16 crystallizes in the orthorhombic Fddd space group. There are two 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(4) atoms to form distorted NaO6 octahedra that share corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Sb(1)O6 octahedra, and  an edgeedge with one S(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 59-82°. In the second Na site, Na(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted NaO6 octahedra that share corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Sb(1)O6 octahedra, and  an edgeedge with one S(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 59-82°. C(1) is bonded in a trigonal planar geometry to one O(1), one O(3), and one O(4) atom. Sb(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form SbO6 octahedra that share edges with two equivalent Na(1)O6 octahedra and edges with two equivalent Na(2)O6 octahedra. S(1) is bonded to four equivalent O(2) atoms to form SO4 tetrahedra that share edges with two equivalent Na(1)O6 octahedra and edges with two equivalent Na(2)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one C(1), and one Sb(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Na(1), one Na(2), and one S(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(2), one C(1), and one Sb(1) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one C(1), and one Sb(1) atom.
Na4C4Sb2SO16 crystallizes in the orthorhombic Fddd space group. There are two 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(4) atoms to form distorted NaO6 octahedra that share corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Sb(1)O6 octahedra, and  an edgeedge with one S(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 59-82°. Both Na(1)-O(1) bond lengths are 2.55 Å. Both Na(1)-O(2) bond lengths are 2.37 Å. Both Na(1)-O(4) bond lengths are 2.56 Å. In the second Na site, Na(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted NaO6 octahedra that share corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Sb(1)O6 octahedra, and  an edgeedge with one S(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 59-82°. Both Na(2)-O(2) bond lengths are 2.35 Å. Both Na(2)-O(3) bond lengths are 2.51 Å. Both Na(2)-O(4) bond lengths are 2.67 Å. C(1) is bonded in a trigonal planar geometry to one O(1), one O(3), and one O(4) atom. The C(1)-O(1) bond length is 1.30 Å. The C(1)-O(3) bond length is 1.29 Å. The C(1)-O(4) bond length is 1.31 Å. Sb(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form SbO6 octahedra that share edges with two equivalent Na(1)O6 octahedra and edges with two equivalent Na(2)O6 octahedra. Both Sb(1)-O(1) bond lengths are 2.31 Å. Both Sb(1)-O(3) bond lengths are 2.31 Å. Both Sb(1)-O(4) bond lengths are 2.32 Å. S(1) is bonded to four equivalent O(2) atoms to form SO4 tetrahedra that share edges with two equivalent Na(1)O6 octahedra and edges with two equivalent Na(2)O6 octahedra. All S(1)-O(2) bond lengths are 1.50 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one C(1), and one Sb(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Na(1), one Na(2), and one S(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(2), one C(1), and one Sb(1) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one C(1), and one Sb(1) atom.