MgCo2(BiO3)4 crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), and two equivalent O(4) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(3), one O(7), one O(8), and two equivalent O(6) atoms to form CoO6 octahedra that share  an edgeedge with one Bi(1)O6 octahedra and  an edgeedge with one Bi(2)O6 octahedra. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one O(9), two equivalent O(4), and two equivalent O(5) atoms. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one O(1), one O(2), one O(7), one O(9), and two equivalent O(4) atoms to form BiO6 octahedra that share  an edgeedge with one Co(1)O6 octahedra and  an edgeedge with one Bi(2)O6 octahedra. In the second Bi site, Bi(2) is bonded to one O(1), one O(3), one O(8), one O(9), and two equivalent O(5) atoms to form BiO6 octahedra that share  an edgeedge with one Co(1)O6 octahedra and  an edgeedge with one Bi(1)O6 octahedra. In the third Bi site, Bi(3) is bonded in a 5-coordinate geometry to one O(7), two equivalent O(4), and two equivalent O(6) atoms. In the fourth Bi site, Bi(4) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(5), and two equivalent O(6) atoms. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a T-shaped geometry to one Mg(1), one Bi(1), and one Bi(2) atom. In the second O site, O(2) is bonded in a T-shaped geometry to one Mg(1), one Co(1), and one Bi(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Co(1), one Bi(2), and one Bi(4) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Co(2), one Bi(1), and one Bi(3) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Co(2), one Bi(2), and one Bi(4) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Co(1), one Bi(3), and one Bi(4) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Co(1), one Bi(1), and one Bi(3) atom. In the eighth O site, O(8) is bonded in a water-like geometry to one Co(1) and one Bi(2) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Co(2), one Bi(1), and one Bi(2) atom.
MgCo2(BiO3)4 crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), and two equivalent O(4) atoms. The Mg(1)-O(1) bond length is 1.98 Å. The Mg(1)-O(2) bond length is 2.00 Å. Both Mg(1)-O(4) bond lengths are 1.99 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(3), one O(7), one O(8), and two equivalent O(6) atoms to form CoO6 octahedra that share  an edgeedge with one Bi(1)O6 octahedra and  an edgeedge with one Bi(2)O6 octahedra. The Co(1)-O(2) bond length is 2.37 Å. The Co(1)-O(3) bond length is 2.04 Å. The Co(1)-O(7) bond length is 2.03 Å. The Co(1)-O(8) bond length is 1.93 Å. Both Co(1)-O(6) bond lengths are 1.97 Å. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one O(9), two equivalent O(4), and two equivalent O(5) atoms. The Co(2)-O(9) bond length is 2.00 Å. Both Co(2)-O(4) bond lengths are 2.25 Å. Both Co(2)-O(5) bond lengths are 1.96 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(7), one O(9), and two equivalent O(4) atoms to form BiO6 octahedra that share  an edgeedge with one Co(1)O6 octahedra and  an edgeedge with one Bi(2)O6 octahedra. The Bi(1)-O(1) bond length is 2.20 Å. The Bi(1)-O(2) bond length is 2.10 Å. The Bi(1)-O(7) bond length is 2.12 Å. The Bi(1)-O(9) bond length is 2.20 Å. Both Bi(1)-O(4) bond lengths are 2.15 Å. In the second Bi site, Bi(2) is bonded to one O(1), one O(3), one O(8), one O(9), and two equivalent O(5) atoms to form BiO6 octahedra that share  an edgeedge with one Co(1)O6 octahedra and  an edgeedge with one Bi(1)O6 octahedra. The Bi(2)-O(1) bond length is 2.16 Å. The Bi(2)-O(3) bond length is 2.20 Å. The Bi(2)-O(8) bond length is 2.09 Å. The Bi(2)-O(9) bond length is 2.32 Å. Both Bi(2)-O(5) bond lengths are 2.14 Å. In the third Bi site, Bi(3) is bonded in a 5-coordinate geometry to one O(7), two equivalent O(4), and two equivalent O(6) atoms. The Bi(3)-O(7) bond length is 2.22 Å. Both Bi(3)-O(4) bond lengths are 2.45 Å. Both Bi(3)-O(6) bond lengths are 2.21 Å. In the fourth Bi site, Bi(4) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(5), and two equivalent O(6) atoms. The Bi(4)-O(3) bond length is 2.22 Å. Both Bi(4)-O(5) bond lengths are 2.27 Å. Both Bi(4)-O(6) bond lengths are 2.26 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a T-shaped geometry to one Mg(1), one Bi(1), and one Bi(2) atom. In the second O site, O(2) is bonded in a T-shaped geometry to one Mg(1), one Co(1), and one Bi(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Co(1), one Bi(2), and one Bi(4) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Co(2), one Bi(1), and one Bi(3) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Co(2), one Bi(2), and one Bi(4) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Co(1), one Bi(3), and one Bi(4) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Co(1), one Bi(1), and one Bi(3) atom. In the eighth O site, O(8) is bonded in a water-like geometry to one Co(1) and one Bi(2) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Co(2), one Bi(1), and one Bi(2) atom.