Na2Mg(BiO3)2 crystallizes in the triclinic P1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), and one O(5) atom. In the second Na site, Na(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form NaO4 trigonal pyramids that share corners with two equivalent Bi(1)O6 octahedra, corners with three equivalent Mg(1)O4 trigonal pyramids, and  an edgeedge with one Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-47°. Mg(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form distorted MgO4 trigonal pyramids that share corners with two equivalent Bi(1)O6 octahedra, corners with three equivalent Na(2)O4 trigonal pyramids, and  an edgeedge with one Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-62°. There are two inequivalent Bi sites. In the first Bi site, Bi(1) 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 BiO6 octahedra that share corners with two equivalent Na(2)O4 trigonal pyramids, corners with two equivalent Mg(1)O4 trigonal pyramids,  an edgeedge with one Na(2)O4 trigonal pyramid, and  an edgeedge with one Mg(1)O4 trigonal pyramid. In the second Bi site, Bi(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. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to one Na(1), one Bi(1), and one Bi(2) atom. In the second O site, O(2) is bonded in a distorted trigonal pyramidal geometry to one Na(1), one Na(2), one Bi(1), and one Bi(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Mg(1), one Bi(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), one Mg(1), one Bi(1), and one Bi(2) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Mg(1), one Bi(1), and one Bi(2) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), one Mg(1), one Bi(1), and one Bi(2) atom.
Na2Mg(BiO3)2 crystallizes in the triclinic P1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), and one O(5) atom. The Na(1)-O(1) bond length is 2.39 Å. The Na(1)-O(2) bond length is 2.39 Å. The Na(1)-O(3) bond length is 2.53 Å. The Na(1)-O(5) bond length is 2.72 Å. In the second Na site, Na(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form NaO4 trigonal pyramids that share corners with two equivalent Bi(1)O6 octahedra, corners with three equivalent Mg(1)O4 trigonal pyramids, and  an edgeedge with one Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-47°. The Na(2)-O(2) bond length is 2.25 Å. The Na(2)-O(4) bond length is 2.42 Å. The Na(2)-O(5) bond length is 2.43 Å. The Na(2)-O(6) bond length is 2.22 Å. Mg(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form distorted MgO4 trigonal pyramids that share corners with two equivalent Bi(1)O6 octahedra, corners with three equivalent Na(2)O4 trigonal pyramids, and  an edgeedge with one Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-62°. The Mg(1)-O(3) bond length is 1.98 Å. The Mg(1)-O(4) bond length is 2.01 Å. The Mg(1)-O(5) bond length is 2.05 Å. The Mg(1)-O(6) bond length is 2.00 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) 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 BiO6 octahedra that share corners with two equivalent Na(2)O4 trigonal pyramids, corners with two equivalent Mg(1)O4 trigonal pyramids,  an edgeedge with one Na(2)O4 trigonal pyramid, and  an edgeedge with one Mg(1)O4 trigonal pyramid. The Bi(1)-O(1) bond length is 2.13 Å. The Bi(1)-O(2) bond length is 2.16 Å. The Bi(1)-O(3) bond length is 2.17 Å. The Bi(1)-O(4) bond length is 2.24 Å. The Bi(1)-O(5) bond length is 2.19 Å. The Bi(1)-O(6) bond length is 2.17 Å. In the second Bi site, Bi(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 Bi(2)-O(1) bond length is 2.25 Å. The Bi(2)-O(2) bond length is 2.25 Å. The Bi(2)-O(3) bond length is 2.56 Å. The Bi(2)-O(4) bond length is 2.32 Å. The Bi(2)-O(5) bond length is 2.69 Å. The Bi(2)-O(6) bond length is 2.37 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to one Na(1), one Bi(1), and one Bi(2) atom. In the second O site, O(2) is bonded in a distorted trigonal pyramidal geometry to one Na(1), one Na(2), one Bi(1), and one Bi(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Mg(1), one Bi(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), one Mg(1), one Bi(1), and one Bi(2) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Mg(1), one Bi(1), and one Bi(2) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), one Mg(1), one Bi(1), and one Bi(2) atom.