Na4Mg(CoO3)2 crystallizes in the triclinic P-1 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(2) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. In the third Na site, Na(3) is bonded in a distorted square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. Mg(1) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(3) atoms. Co(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form distorted edge-sharing CoO5 trigonal bipyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), and two equivalent Co(1) atoms. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), one Mg(1), and one Co(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Mg(1), and two equivalent Co(1) atoms.
Na4Mg(CoO3)2 crystallizes in the triclinic P-1 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(2) atoms. The Na(1)-O(3) bond length is 2.54 Å. There is one shorter (2.29 Å) and one longer (2.40 Å) Na(1)-O(1) bond length. There is one shorter (2.43 Å) and one longer (2.45 Å) Na(1)-O(2) bond length. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Both Na(2)-O(1) bond lengths are 2.45 Å. Both Na(2)-O(2) bond lengths are 2.50 Å. Both Na(2)-O(3) bond lengths are 2.26 Å. In the third Na site, Na(3) is bonded in a distorted square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Na(3)-O(1) bond lengths are 2.33 Å. Both Na(3)-O(2) bond lengths are 2.49 Å. Mg(1) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(3) atoms. Both Mg(1)-O(2) bond lengths are 2.03 Å. Both Mg(1)-O(3) bond lengths are 1.96 Å. Co(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form distorted edge-sharing CoO5 trigonal bipyramids. The Co(1)-O(2) bond length is 1.86 Å. There is one shorter (1.99 Å) and one longer (2.13 Å) Co(1)-O(1) bond length. There is one shorter (1.86 Å) and one longer (2.21 Å) Co(1)-O(3) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), and two equivalent Co(1) atoms. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), one Mg(1), and one Co(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Mg(1), and two equivalent Co(1) atoms.