MgCd2(BiO3)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a trigonal planar geometry to one O(4), one O(5), and one O(6) atom. There are two inequivalent Cd sites. In the first Cd site, Cd(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 CdO6 octahedra that share corners with three equivalent Cd(2)O6 octahedra, edges with three equivalent Bi(2)O6 octahedra, and  a faceface with one Cd(2)O6 octahedra. The corner-sharing octahedral tilt angles are 48°. In the second Cd site, Cd(2) 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 CdO6 octahedra that share corners with three equivalent Cd(1)O6 octahedra, corners with three equivalent Bi(2)O6 octahedra,  a faceface with one Cd(1)O6 octahedra, and  a faceface with one Bi(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-49°. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. In the second Bi site, Bi(2) 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 three equivalent Cd(2)O6 octahedra, edges with three equivalent Cd(1)O6 octahedra, and  a faceface with one Cd(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-49°. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Cd(1), one Cd(2), one Bi(1), and one Bi(2) atom to form a mixture of distorted corner and edge-sharing OCd2Bi2 trigonal pyramids. In the second O site, O(2) is bonded to one Cd(1), one Cd(2), one Bi(1), and one Bi(2) atom to form a mixture of distorted corner and edge-sharing OCd2Bi2 trigonal pyramids. In the third O site, O(3) is bonded to one Cd(1), one Cd(2), one Bi(1), and one Bi(2) atom to form a mixture of distorted corner and edge-sharing OCd2Bi2 trigonal pyramids. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), one Cd(1), one Cd(2), and one Bi(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Mg(1), one Cd(1), one Cd(2), and one Bi(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Mg(1), one Cd(1), one Cd(2), and one Bi(2) atom.
MgCd2(BiO3)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a trigonal planar geometry to one O(4), one O(5), and one O(6) atom. The Mg(1)-O(4) bond length is 1.96 Å. The Mg(1)-O(5) bond length is 1.96 Å. The Mg(1)-O(6) bond length is 1.96 Å. There are two inequivalent Cd sites. In the first Cd site, Cd(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 CdO6 octahedra that share corners with three equivalent Cd(2)O6 octahedra, edges with three equivalent Bi(2)O6 octahedra, and  a faceface with one Cd(2)O6 octahedra. The corner-sharing octahedral tilt angles are 48°. The Cd(1)-O(1) bond length is 2.31 Å. The Cd(1)-O(2) bond length is 2.31 Å. The Cd(1)-O(3) bond length is 2.31 Å. The Cd(1)-O(4) bond length is 2.53 Å. The Cd(1)-O(5) bond length is 2.54 Å. The Cd(1)-O(6) bond length is 2.54 Å. In the second Cd site, Cd(2) 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 CdO6 octahedra that share corners with three equivalent Cd(1)O6 octahedra, corners with three equivalent Bi(2)O6 octahedra,  a faceface with one Cd(1)O6 octahedra, and  a faceface with one Bi(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-49°. The Cd(2)-O(1) bond length is 2.48 Å. The Cd(2)-O(2) bond length is 2.47 Å. The Cd(2)-O(3) bond length is 2.47 Å. The Cd(2)-O(4) bond length is 2.33 Å. The Cd(2)-O(5) bond length is 2.32 Å. The Cd(2)-O(6) bond length is 2.33 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. The Bi(1)-O(1) bond length is 2.19 Å. The Bi(1)-O(2) bond length is 2.19 Å. The Bi(1)-O(3) bond length is 2.19 Å. In the second Bi site, Bi(2) 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 three equivalent Cd(2)O6 octahedra, edges with three equivalent Cd(1)O6 octahedra, and  a faceface with one Cd(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-49°. The Bi(2)-O(1) bond length is 2.42 Å. The Bi(2)-O(2) bond length is 2.42 Å. The Bi(2)-O(3) bond length is 2.42 Å. The Bi(2)-O(4) bond length is 2.36 Å. The Bi(2)-O(5) bond length is 2.36 Å. The Bi(2)-O(6) bond length is 2.36 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Cd(1), one Cd(2), one Bi(1), and one Bi(2) atom to form a mixture of distorted corner and edge-sharing OCd2Bi2 trigonal pyramids. In the second O site, O(2) is bonded to one Cd(1), one Cd(2), one Bi(1), and one Bi(2) atom to form a mixture of distorted corner and edge-sharing OCd2Bi2 trigonal pyramids. In the third O site, O(3) is bonded to one Cd(1), one Cd(2), one Bi(1), and one Bi(2) atom to form a mixture of distorted corner and edge-sharing OCd2Bi2 trigonal pyramids. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), one Cd(1), one Cd(2), and one Bi(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Mg(1), one Cd(1), one Cd(2), and one Bi(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Mg(1), one Cd(1), one Cd(2), and one Bi(2) atom.