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 distorted MgO4 tetrahedra that share  a cornercorner with one Bi(1)O6 octahedra,  a cornercorner with one Bi(3)O5 square pyramid, and  an edgeedge with one Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles are 62°. 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(6), one O(7), and one O(8) atom to form BiO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra, edges with two equivalent Bi(3)O5 square pyramids, and  an edgeedge with one Mg(1)O4 tetrahedra. In the second Bi site, Bi(2) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(5), one O(7), and one O(8) atom. In the third Bi site, Bi(3) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(6) atom to form distorted BiO5 square pyramids that share  a cornercorner with one Mg(1)O4 tetrahedra and edges with two equivalent Bi(1)O6 octahedra. In the fourth Bi site, Bi(4) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(5), and one O(6) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to one Bi(1) and one Bi(3) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Bi(1), one Bi(3), and one Bi(4) atom. In the third O site, O(3) is bonded in a trigonal planar 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 planar geometry to one Bi(1), one Bi(2), and one Bi(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1), one Bi(2), and one Bi(4) atom. In the sixth O site, O(6) is bonded in a distorted trigonal pyramidal geometry to one Mg(1), one Bi(1), one Bi(3), and one Bi(4) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Bi(1), and one Bi(2) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Mg(1), one Bi(1), and one Bi(2) 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 distorted MgO4 tetrahedra that share  a cornercorner with one Bi(1)O6 octahedra,  a cornercorner with one Bi(3)O5 square pyramid, and  an edgeedge with one Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles are 62°. The Mg(1)-O(5) bond length is 1.98 Å. The Mg(1)-O(6) bond length is 1.98 Å. The Mg(1)-O(7) bond length is 2.01 Å. The Mg(1)-O(8) bond length is 1.98 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(6), one O(7), and one O(8) atom to form BiO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra, edges with two equivalent Bi(3)O5 square pyramids, and  an edgeedge with one Mg(1)O4 tetrahedra. The Bi(1)-O(1) bond length is 2.11 Å. The Bi(1)-O(2) bond length is 2.17 Å. The Bi(1)-O(4) bond length is 2.18 Å. The Bi(1)-O(6) bond length is 2.21 Å. The Bi(1)-O(7) bond length is 2.26 Å. The Bi(1)-O(8) bond length is 2.08 Å. In the second Bi site, Bi(2) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(5), one O(7), and one O(8) atom. The Bi(2)-O(3) bond length is 2.15 Å. The Bi(2)-O(4) bond length is 2.46 Å. The Bi(2)-O(5) bond length is 2.32 Å. The Bi(2)-O(7) bond length is 2.20 Å. The Bi(2)-O(8) bond length is 2.76 Å. In the third Bi site, Bi(3) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(6) atom to form distorted BiO5 square pyramids that share  a cornercorner with one Mg(1)O4 tetrahedra and edges with two equivalent Bi(1)O6 octahedra. The Bi(3)-O(1) bond length is 2.27 Å. The Bi(3)-O(2) bond length is 2.48 Å. The Bi(3)-O(3) bond length is 2.42 Å. The Bi(3)-O(4) bond length is 2.22 Å. The Bi(3)-O(6) bond length is 2.44 Å. In the fourth Bi site, Bi(4) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(5), and one O(6) atom. The Bi(4)-O(2) bond length is 2.21 Å. The Bi(4)-O(3) bond length is 2.28 Å. The Bi(4)-O(5) bond length is 2.17 Å. The Bi(4)-O(6) bond length is 2.49 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to one Bi(1) and one Bi(3) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Bi(1), one Bi(3), and one Bi(4) atom. In the third O site, O(3) is bonded in a trigonal planar 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 planar geometry to one Bi(1), one Bi(2), and one Bi(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1), one Bi(2), and one Bi(4) atom. In the sixth O site, O(6) is bonded in a distorted trigonal pyramidal geometry to one Mg(1), one Bi(1), one Bi(3), and one Bi(4) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Bi(1), and one Bi(2) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Mg(1), one Bi(1), and one Bi(2) atom.