Mg(BiO2)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form MgO4 tetrahedra that share corners with three equivalent Bi(1)O6 octahedra, corners with three equivalent Bi(2)O6 octahedra, corners with three equivalent Bi(3)O6 octahedra, and corners with three equivalent Bi(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-55°. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(7), and one O(8) atom to form BiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Bi(2)O6 octahedra, edges with two equivalent Bi(3)O6 octahedra, and edges with two equivalent Bi(4)O6 octahedra. In the second Bi site, Bi(2) is bonded to one O(1), one O(2), one O(3), one O(6), one O(7), and one O(8) atom to form BiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Bi(1)O6 octahedra, edges with two equivalent Bi(3)O6 octahedra, and edges with two equivalent Bi(4)O6 octahedra. In the third Bi site, Bi(3) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form BiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Bi(1)O6 octahedra, edges with two equivalent Bi(2)O6 octahedra, and edges with two equivalent Bi(4)O6 octahedra. In the fourth Bi site, Bi(4) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form BiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Bi(1)O6 octahedra, edges with two equivalent Bi(2)O6 octahedra, and edges with two equivalent Bi(3)O6 octahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Bi(1), one Bi(2), and one Bi(3) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Bi(1), one Bi(2), and one Bi(4) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Bi(2), one Bi(3), and one Bi(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Bi(1), one Bi(3), and one Bi(4) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Bi(1), one Bi(3), and one Bi(4) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Bi(2), one Bi(3), and one Bi(4) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Bi(1), one Bi(2), and one Bi(4) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Bi(1), one Bi(2), and one Bi(3) atom.
Mg(BiO2)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form MgO4 tetrahedra that share corners with three equivalent Bi(1)O6 octahedra, corners with three equivalent Bi(2)O6 octahedra, corners with three equivalent Bi(3)O6 octahedra, and corners with three equivalent Bi(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-55°. The Mg(1)-O(5) bond length is 2.10 Å. The Mg(1)-O(6) bond length is 2.05 Å. The Mg(1)-O(7) bond length is 2.06 Å. The Mg(1)-O(8) bond length is 2.11 Å. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(7), and one O(8) atom to form BiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Bi(2)O6 octahedra, edges with two equivalent Bi(3)O6 octahedra, and edges with two equivalent Bi(4)O6 octahedra. The Bi(1)-O(1) bond length is 2.26 Å. The Bi(1)-O(2) bond length is 2.25 Å. The Bi(1)-O(4) bond length is 2.26 Å. The Bi(1)-O(5) bond length is 2.46 Å. The Bi(1)-O(7) bond length is 2.43 Å. The Bi(1)-O(8) bond length is 2.46 Å. In the second Bi site, Bi(2) is bonded to one O(1), one O(2), one O(3), one O(6), one O(7), and one O(8) atom to form BiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Bi(1)O6 octahedra, edges with two equivalent Bi(3)O6 octahedra, and edges with two equivalent Bi(4)O6 octahedra. The Bi(2)-O(1) bond length is 2.27 Å. The Bi(2)-O(2) bond length is 2.27 Å. The Bi(2)-O(3) bond length is 2.26 Å. The Bi(2)-O(6) bond length is 2.50 Å. The Bi(2)-O(7) bond length is 2.50 Å. The Bi(2)-O(8) bond length is 2.52 Å. In the third Bi site, Bi(3) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form BiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Bi(1)O6 octahedra, edges with two equivalent Bi(2)O6 octahedra, and edges with two equivalent Bi(4)O6 octahedra. The Bi(3)-O(1) bond length is 2.26 Å. The Bi(3)-O(3) bond length is 2.25 Å. The Bi(3)-O(4) bond length is 2.26 Å. The Bi(3)-O(5) bond length is 2.47 Å. The Bi(3)-O(6) bond length is 2.43 Å. The Bi(3)-O(8) bond length is 2.47 Å. In the fourth Bi site, Bi(4) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form BiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Bi(1)O6 octahedra, edges with two equivalent Bi(2)O6 octahedra, and edges with two equivalent Bi(3)O6 octahedra. The Bi(4)-O(2) bond length is 2.27 Å. The Bi(4)-O(3) bond length is 2.27 Å. The Bi(4)-O(4) bond length is 2.27 Å. The Bi(4)-O(5) bond length is 2.53 Å. The Bi(4)-O(6) bond length is 2.50 Å. The Bi(4)-O(7) bond length is 2.51 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Bi(1), one Bi(2), and one Bi(3) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Bi(1), one Bi(2), and one Bi(4) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Bi(2), one Bi(3), and one Bi(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Bi(1), one Bi(3), and one Bi(4) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Bi(1), one Bi(3), and one Bi(4) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Bi(2), one Bi(3), and one Bi(4) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Bi(1), one Bi(2), and one Bi(4) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Bi(1), one Bi(2), and one Bi(3) atom.