Na5CuO4 is Ilmenite-like structured and crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form distorted NaO4 tetrahedra that share corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Cu(1)O4 tetrahedra, corners with eight equivalent Na(1)O4 tetrahedra,  an edgeedge with one Na(2)O4 tetrahedra,  an edgeedge with one Cu(1)O4 tetrahedra, and edges with two equivalent Na(1)O4 tetrahedra. In the second Na site, Na(2) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form NaO4 tetrahedra that share corners with four equivalent Cu(1)O4 tetrahedra, corners with eight equivalent Na(1)O4 tetrahedra, and edges with four equivalent Na(1)O4 tetrahedra. Cu(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form CuO4 tetrahedra that share corners with four equivalent Na(2)O4 tetrahedra, corners with eight equivalent Na(1)O4 tetrahedra, and edges with four equivalent Na(1)O4 tetrahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), four equivalent Na(1), and one Cu(1) atom to form a mixture of corner and edge-sharing ONa5Cu octahedra. The corner-sharing octahedral tilt angles range from 57-60°. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(2), four equivalent Na(1), and one Cu(1) atom.
Na5CuO4 is Ilmenite-like structured and crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form distorted NaO4 tetrahedra that share corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Cu(1)O4 tetrahedra, corners with eight equivalent Na(1)O4 tetrahedra,  an edgeedge with one Na(2)O4 tetrahedra,  an edgeedge with one Cu(1)O4 tetrahedra, and edges with two equivalent Na(1)O4 tetrahedra. There is one shorter (2.31 Å) and one longer (2.34 Å) Na(1)-O(1) bond length. There is one shorter (2.35 Å) and one longer (2.41 Å) Na(1)-O(2) bond length. In the second Na site, Na(2) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form NaO4 tetrahedra that share corners with four equivalent Cu(1)O4 tetrahedra, corners with eight equivalent Na(1)O4 tetrahedra, and edges with four equivalent Na(1)O4 tetrahedra. Both Na(2)-O(1) bond lengths are 2.33 Å. Both Na(2)-O(2) bond lengths are 2.30 Å. Cu(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form CuO4 tetrahedra that share corners with four equivalent Na(2)O4 tetrahedra, corners with eight equivalent Na(1)O4 tetrahedra, and edges with four equivalent Na(1)O4 tetrahedra. Both Cu(1)-O(1) bond lengths are 1.96 Å. Both Cu(1)-O(2) bond lengths are 1.94 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), four equivalent Na(1), and one Cu(1) atom to form a mixture of corner and edge-sharing ONa5Cu octahedra. The corner-sharing octahedral tilt angles range from 57-60°. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(2), four equivalent Na(1), and one Cu(1) atom.