Na4Mg(CoO3)2 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), one O(5), and one O(6) atom. In the fourth Na site, Na(4) is bonded in a 3-coordinate geometry to one O(1), one O(3), one O(4), and one O(5) atom. Mg(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form MgO5 trigonal bipyramids that share  a cornercorner with one Co(1)O4 tetrahedra, corners with three equivalent Co(2)O4 tetrahedra, and  an edgeedge with one Co(1)O4 tetrahedra. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form distorted CoO4 tetrahedra that share  a cornercorner with one Mg(1)O5 trigonal bipyramid,  an edgeedge with one Co(2)O4 tetrahedra, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. In the second Co site, Co(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form CoO4 tetrahedra that share corners with three equivalent Mg(1)O5 trigonal bipyramids and  an edgeedge with one Co(1)O4 tetrahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mg(1), one Co(1), and one Co(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Mg(1), and one Co(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mg(1), and one Co(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Mg(1), and one Co(2) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mg(1), and one Co(2) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Co(1), and one Co(2) atom.
Na4Mg(CoO3)2 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Na(1)-O(1) bond length is 2.64 Å. The Na(1)-O(2) bond length is 2.56 Å. The Na(1)-O(3) bond length is 2.37 Å. The Na(1)-O(4) bond length is 2.40 Å. The Na(1)-O(5) bond length is 2.55 Å. The Na(1)-O(6) bond length is 2.34 Å. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Na(2)-O(1) bond length is 2.55 Å. The Na(2)-O(2) bond length is 2.45 Å. The Na(2)-O(3) bond length is 2.66 Å. The Na(2)-O(4) bond length is 2.62 Å. The Na(2)-O(5) bond length is 2.56 Å. The Na(2)-O(6) bond length is 2.30 Å. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), one O(5), and one O(6) atom. The Na(3)-O(1) bond length is 2.89 Å. The Na(3)-O(2) bond length is 2.25 Å. The Na(3)-O(3) bond length is 2.40 Å. The Na(3)-O(5) bond length is 2.40 Å. The Na(3)-O(6) bond length is 2.31 Å. In the fourth Na site, Na(4) is bonded in a 3-coordinate geometry to one O(1), one O(3), one O(4), and one O(5) atom. The Na(4)-O(1) bond length is 2.85 Å. The Na(4)-O(3) bond length is 2.39 Å. The Na(4)-O(4) bond length is 2.45 Å. The Na(4)-O(5) bond length is 2.41 Å. Mg(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form MgO5 trigonal bipyramids that share  a cornercorner with one Co(1)O4 tetrahedra, corners with three equivalent Co(2)O4 tetrahedra, and  an edgeedge with one Co(1)O4 tetrahedra. The Mg(1)-O(1) bond length is 2.17 Å. The Mg(1)-O(2) bond length is 2.09 Å. The Mg(1)-O(3) bond length is 2.27 Å. The Mg(1)-O(4) bond length is 2.02 Å. The Mg(1)-O(5) bond length is 2.04 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form distorted CoO4 tetrahedra that share  a cornercorner with one Mg(1)O5 trigonal bipyramid,  an edgeedge with one Co(2)O4 tetrahedra, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The Co(1)-O(1) bond length is 2.01 Å. The Co(1)-O(2) bond length is 1.79 Å. The Co(1)-O(3) bond length is 1.81 Å. The Co(1)-O(6) bond length is 1.95 Å. In the second Co site, Co(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form CoO4 tetrahedra that share corners with three equivalent Mg(1)O5 trigonal bipyramids and  an edgeedge with one Co(1)O4 tetrahedra. The Co(2)-O(1) bond length is 2.05 Å. The Co(2)-O(4) bond length is 1.81 Å. The Co(2)-O(5) bond length is 1.84 Å. The Co(2)-O(6) bond length is 1.92 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mg(1), one Co(1), and one Co(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Mg(1), and one Co(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mg(1), and one Co(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Mg(1), and one Co(2) atom. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mg(1), and one Co(2) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Co(1), and one Co(2) atom.