Na4CuO3 crystallizes in the monoclinic Cc space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted see-saw-like geometry to one O(1), one O(2), and two equivalent O(3) atoms. In the second Na site, Na(2) is bonded in a 3-coordinate geometry to one O(2), one O(3), and two equivalent O(1) atoms. In the third Na site, Na(3) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. In the fourth Na site, Na(4) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form distorted corner-sharing NaO4 trigonal pyramids. Cu(1) is bonded in a distorted trigonal planar geometry to one O(1), one O(2), and one O(3) atom. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), one Na(4), two equivalent Na(2), and one Cu(1) atom to form a mixture of distorted corner and edge-sharing ONa5Cu octahedra. The corner-sharing octahedral tilt angles range from 44-56°. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), two equivalent Na(4), and one Cu(1) atom. In the third O site, O(3) is bonded to one Na(2), one Na(3), one Na(4), two 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 44-62°.
Na4CuO3 crystallizes in the monoclinic Cc space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted see-saw-like geometry to one O(1), one O(2), and two equivalent O(3) atoms. The Na(1)-O(1) bond length is 2.51 Å. The Na(1)-O(2) bond length is 2.40 Å. There is one shorter (2.36 Å) and one longer (2.39 Å) Na(1)-O(3) bond length. In the second Na site, Na(2) is bonded in a 3-coordinate geometry to one O(2), one O(3), and two equivalent O(1) atoms. The Na(2)-O(2) bond length is 2.79 Å. The Na(2)-O(3) bond length is 2.30 Å. There is one shorter (2.31 Å) and one longer (2.32 Å) Na(2)-O(1) bond length. In the third Na site, Na(3) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The Na(3)-O(1) bond length is 2.25 Å. The Na(3)-O(2) bond length is 2.29 Å. The Na(3)-O(3) bond length is 2.29 Å. In the fourth Na site, Na(4) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form distorted corner-sharing NaO4 trigonal pyramids. The Na(4)-O(1) bond length is 2.35 Å. The Na(4)-O(3) bond length is 2.28 Å. There is one shorter (2.29 Å) and one longer (2.35 Å) Na(4)-O(2) bond length. Cu(1) is bonded in a distorted trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The Cu(1)-O(1) bond length is 1.91 Å. The Cu(1)-O(2) bond length is 1.85 Å. The Cu(1)-O(3) bond length is 1.93 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), one Na(4), two equivalent Na(2), and one Cu(1) atom to form a mixture of distorted corner and edge-sharing ONa5Cu octahedra. The corner-sharing octahedral tilt angles range from 44-56°. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), two equivalent Na(4), and one Cu(1) atom. In the third O site, O(3) is bonded to one Na(2), one Na(3), one Na(4), two 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 44-62°.