Na6CuO4 crystallizes in the tetragonal P4_2/nmc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to four equivalent O(1) atoms to form distorted NaO4 tetrahedra that share corners with two equivalent Cu(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, corners with eight equivalent Na(1)O4 tetrahedra,  an edgeedge with one Cu(1)O4 tetrahedra, edges with two equivalent Na(1)O4 tetrahedra, and edges with two equivalent Na(2)O4 tetrahedra. In the second Na site, Na(2) is bonded to four equivalent O(1) atoms to form NaO4 tetrahedra that share corners with four equivalent Cu(1)O4 tetrahedra, corners with eight equivalent Na(1)O4 tetrahedra, edges with two equivalent Na(2)O4 tetrahedra, and edges with four equivalent Na(1)O4 tetrahedra. Cu(1) is bonded to four equivalent O(1) atoms to form distorted CuO4 tetrahedra that share corners with eight equivalent Na(1)O4 tetrahedra, corners with eight equivalent Na(2)O4 tetrahedra, and edges with four equivalent Na(1)O4 tetrahedra. O(1) is bonded to two equivalent Na(2), four equivalent Na(1), and one Cu(1) atom to form a mixture of distorted corner and edge-sharing ONa6Cu pentagonal bipyramids.
Na6CuO4 crystallizes in the tetragonal P4_2/nmc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to four equivalent O(1) atoms to form distorted NaO4 tetrahedra that share corners with two equivalent Cu(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, corners with eight equivalent Na(1)O4 tetrahedra,  an edgeedge with one Cu(1)O4 tetrahedra, edges with two equivalent Na(1)O4 tetrahedra, and edges with two equivalent Na(2)O4 tetrahedra. There are two shorter (2.37 Å) and two longer (2.41 Å) Na(1)-O(1) bond lengths. In the second Na site, Na(2) is bonded to four equivalent O(1) atoms to form NaO4 tetrahedra that share corners with four equivalent Cu(1)O4 tetrahedra, corners with eight equivalent Na(1)O4 tetrahedra, edges with two equivalent Na(2)O4 tetrahedra, and edges with four equivalent Na(1)O4 tetrahedra. There are two shorter (2.27 Å) and two longer (2.36 Å) Na(2)-O(1) bond lengths. Cu(1) is bonded to four equivalent O(1) atoms to form distorted CuO4 tetrahedra that share corners with eight equivalent Na(1)O4 tetrahedra, corners with eight equivalent Na(2)O4 tetrahedra, and edges with four equivalent Na(1)O4 tetrahedra. All Cu(1)-O(1) bond lengths are 2.07 Å. O(1) is bonded to two equivalent Na(2), four equivalent Na(1), and one Cu(1) atom to form a mixture of distorted corner and edge-sharing ONa6Cu pentagonal bipyramids.