Na4Mg(BiO3)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 4-coordinate geometry to one O(1), one O(3), one O(4), and one O(6) atom. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(4), and one O(6) atom. In the third Na site, Na(3) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form a mixture of distorted corner and edge-sharing NaO4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 15-71°. In the fourth Na site, Na(4) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form a mixture of distorted corner and edge-sharing NaO6 octahedra. Mg(1) is bonded in a rectangular see-saw-like geometry to one O(2), one O(3), one O(5), and one O(6) atom. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 3-coordinate geometry to one O(1), one O(4), and one O(5) atom. In the second Bi site, Bi(2) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(4), one O(5), and one O(6) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal bipyramidal geometry to one Na(1), one Na(2), one Na(3), one Na(4), and one Bi(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), one Na(4), one Mg(1), and one Bi(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(1), one Na(3), one Na(4), one Mg(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Bi(1), and one Bi(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(4), one Mg(1), one Bi(1), and one Bi(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(4), one Mg(1), and one Bi(2) atom.
Na4Mg(BiO3)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 4-coordinate geometry to one O(1), one O(3), one O(4), and one O(6) atom. The Na(1)-O(1) bond length is 2.42 Å. The Na(1)-O(3) bond length is 2.58 Å. The Na(1)-O(4) bond length is 2.42 Å. The Na(1)-O(6) bond length is 2.27 Å. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(4), and one O(6) atom. The Na(2)-O(1) bond length is 2.45 Å. The Na(2)-O(2) bond length is 2.25 Å. The Na(2)-O(4) bond length is 2.44 Å. The Na(2)-O(6) bond length is 2.51 Å. In the third Na site, Na(3) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form a mixture of distorted corner and edge-sharing NaO4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 15-71°. The Na(3)-O(1) bond length is 2.40 Å. The Na(3)-O(2) bond length is 2.35 Å. The Na(3)-O(3) bond length is 2.28 Å. The Na(3)-O(4) bond length is 2.39 Å. In the fourth Na site, Na(4) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form a mixture of distorted corner and edge-sharing NaO6 octahedra. The Na(4)-O(1) bond length is 2.56 Å. The Na(4)-O(2) bond length is 2.96 Å. The Na(4)-O(3) bond length is 2.49 Å. The Na(4)-O(4) bond length is 2.79 Å. The Na(4)-O(5) bond length is 2.41 Å. The Na(4)-O(6) bond length is 2.58 Å. Mg(1) is bonded in a rectangular see-saw-like geometry to one O(2), one O(3), one O(5), and one O(6) atom. The Mg(1)-O(2) bond length is 2.01 Å. The Mg(1)-O(3) bond length is 2.05 Å. The Mg(1)-O(5) bond length is 1.91 Å. The Mg(1)-O(6) bond length is 2.01 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 3-coordinate geometry to one O(1), one O(4), and one O(5) atom. The Bi(1)-O(1) bond length is 2.12 Å. The Bi(1)-O(4) bond length is 2.14 Å. The Bi(1)-O(5) bond length is 2.15 Å. In the second Bi site, Bi(2) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Bi(2)-O(2) bond length is 2.24 Å. The Bi(2)-O(3) bond length is 2.19 Å. The Bi(2)-O(4) bond length is 2.83 Å. The Bi(2)-O(5) bond length is 2.61 Å. The Bi(2)-O(6) bond length is 2.23 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal bipyramidal geometry to one Na(1), one Na(2), one Na(3), one Na(4), and one Bi(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), one Na(4), one Mg(1), and one Bi(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(1), one Na(3), one Na(4), one Mg(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Bi(1), and one Bi(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(4), one Mg(1), one Bi(1), and one Bi(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(4), one Mg(1), and one Bi(2) atom.