MgFe2(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 Fe sites. In the first Fe site, Fe(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. In the second Fe site, Fe(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 FeO6 octahedra that share corners with three equivalent Bi(1)O6 octahedra, corners with three equivalent Bi(2)O6 octahedra,  a faceface with one Bi(1)O6 octahedra, and  a faceface with one Bi(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-57°. 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 distorted BiO6 octahedra that share corners with three equivalent Fe(2)O6 octahedra, edges with three equivalent Bi(2)O6 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-57°. 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 distorted BiO6 octahedra that share corners with three equivalent Fe(2)O6 octahedra, edges with three equivalent Bi(1)O6 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-57°. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Fe(1), one Fe(2), one Bi(1), and one Bi(2) atom to form distorted OFe2Bi2 trigonal pyramids that share  a cornercorner with one O(6)MgFeBi2 trigonal pyramid, corners with two equivalent O(2)Fe2Bi2 trigonal pyramids, corners with two equivalent O(3)Fe2Bi2 trigonal pyramids, corners with three equivalent O(4)MgFeBi2 trigonal pyramids, corners with three equivalent O(5)MgFeBi2 trigonal pyramids,  an edgeedge with one O(2)Fe2Bi2 trigonal pyramid,  an edgeedge with one O(3)Fe2Bi2 trigonal pyramid, and  an edgeedge with one O(6)MgFeBi2 trigonal pyramid. In the second O site, O(2) is bonded to one Fe(1), one Fe(2), one Bi(1), and one Bi(2) atom to form distorted OFe2Bi2 trigonal pyramids that share  a cornercorner with one O(4)MgFeBi2 trigonal pyramid, corners with two equivalent O(1)Fe2Bi2 trigonal pyramids, corners with two equivalent O(3)Fe2Bi2 trigonal pyramids, corners with three equivalent O(5)MgFeBi2 trigonal pyramids, corners with three equivalent O(6)MgFeBi2 trigonal pyramids,  an edgeedge with one O(1)Fe2Bi2 trigonal pyramid,  an edgeedge with one O(3)Fe2Bi2 trigonal pyramid, and  an edgeedge with one O(4)MgFeBi2 trigonal pyramid. In the third O site, O(3) is bonded to one Fe(1), one Fe(2), one Bi(1), and one Bi(2) atom to form distorted OFe2Bi2 trigonal pyramids that share  a cornercorner with one O(5)MgFeBi2 trigonal pyramid, corners with two equivalent O(1)Fe2Bi2 trigonal pyramids, corners with two equivalent O(2)Fe2Bi2 trigonal pyramids, corners with three equivalent O(4)MgFeBi2 trigonal pyramids, corners with three equivalent O(6)MgFeBi2 trigonal pyramids,  an edgeedge with one O(1)Fe2Bi2 trigonal pyramid,  an edgeedge with one O(2)Fe2Bi2 trigonal pyramid, and  an edgeedge with one O(5)MgFeBi2 trigonal pyramid. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(2), one Bi(1), and one Bi(2) atom to form distorted OMgFeBi2 trigonal pyramids that share  a cornercorner with one O(2)Fe2Bi2 trigonal pyramid, corners with two equivalent O(5)MgFeBi2 trigonal pyramids, corners with two equivalent O(6)MgFeBi2 trigonal pyramids, corners with three equivalent O(1)Fe2Bi2 trigonal pyramids, corners with three equivalent O(3)Fe2Bi2 trigonal pyramids,  an edgeedge with one O(2)Fe2Bi2 trigonal pyramid,  an edgeedge with one O(5)MgFeBi2 trigonal pyramid, and  an edgeedge with one O(6)MgFeBi2 trigonal pyramid. In the fifth O site, O(5) is bonded to one Mg(1), one Fe(2), one Bi(1), and one Bi(2) atom to form distorted OMgFeBi2 trigonal pyramids that share  a cornercorner with one O(3)Fe2Bi2 trigonal pyramid, corners with two equivalent O(4)MgFeBi2 trigonal pyramids, corners with two equivalent O(6)MgFeBi2 trigonal pyramids, corners with three equivalent O(1)Fe2Bi2 trigonal pyramids, corners with three equivalent O(2)Fe2Bi2 trigonal pyramids,  an edgeedge with one O(3)Fe2Bi2 trigonal pyramid,  an edgeedge with one O(4)MgFeBi2 trigonal pyramid, and  an edgeedge with one O(6)MgFeBi2 trigonal pyramid. In the sixth O site, O(6) is bonded to one Mg(1), one Fe(2), one Bi(1), and one Bi(2) atom to form distorted OMgFeBi2 trigonal pyramids that share  a cornercorner with one O(1)Fe2Bi2 trigonal pyramid, corners with two equivalent O(4)MgFeBi2 trigonal pyramids, corners with two equivalent O(5)MgFeBi2 trigonal pyramids, corners with three equivalent O(2)Fe2Bi2 trigonal pyramids, corners with three equivalent O(3)Fe2Bi2 trigonal pyramids,  an edgeedge with one O(1)Fe2Bi2 trigonal pyramid,  an edgeedge with one O(4)MgFeBi2 trigonal pyramid, and  an edgeedge with one O(5)MgFeBi2 trigonal pyramid.
MgFe2(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 1.95 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The Fe(1)-O(1) bond length is 1.95 Å. The Fe(1)-O(2) bond length is 1.95 Å. The Fe(1)-O(3) bond length is 1.95 Å. In the second Fe site, Fe(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 FeO6 octahedra that share corners with three equivalent Bi(1)O6 octahedra, corners with three equivalent Bi(2)O6 octahedra,  a faceface with one Bi(1)O6 octahedra, and  a faceface with one Bi(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-57°. The Fe(2)-O(1) bond length is 2.23 Å. The Fe(2)-O(2) bond length is 2.24 Å. The Fe(2)-O(3) bond length is 2.15 Å. The Fe(2)-O(4) bond length is 2.25 Å. The Fe(2)-O(5) bond length is 2.15 Å. The Fe(2)-O(6) bond length is 2.23 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 distorted BiO6 octahedra that share corners with three equivalent Fe(2)O6 octahedra, edges with three equivalent Bi(2)O6 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-57°. The Bi(1)-O(1) bond length is 2.50 Å. The Bi(1)-O(2) bond length is 2.48 Å. The Bi(1)-O(3) bond length is 2.52 Å. The Bi(1)-O(4) bond length is 2.31 Å. The Bi(1)-O(5) bond length is 2.34 Å. The Bi(1)-O(6) bond length is 2.30 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 distorted BiO6 octahedra that share corners with three equivalent Fe(2)O6 octahedra, edges with three equivalent Bi(1)O6 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-57°. The Bi(2)-O(1) bond length is 2.35 Å. The Bi(2)-O(2) bond length is 2.36 Å. The Bi(2)-O(3) bond length is 2.39 Å. The Bi(2)-O(4) bond length is 2.44 Å. The Bi(2)-O(5) bond length is 2.48 Å. The Bi(2)-O(6) bond length is 2.45 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Fe(1), one Fe(2), one Bi(1), and one Bi(2) atom to form distorted OFe2Bi2 trigonal pyramids that share  a cornercorner with one O(6)MgFeBi2 trigonal pyramid, corners with two equivalent O(2)Fe2Bi2 trigonal pyramids, corners with two equivalent O(3)Fe2Bi2 trigonal pyramids, corners with three equivalent O(4)MgFeBi2 trigonal pyramids, corners with three equivalent O(5)MgFeBi2 trigonal pyramids,  an edgeedge with one O(2)Fe2Bi2 trigonal pyramid,  an edgeedge with one O(3)Fe2Bi2 trigonal pyramid, and  an edgeedge with one O(6)MgFeBi2 trigonal pyramid. In the second O site, O(2) is bonded to one Fe(1), one Fe(2), one Bi(1), and one Bi(2) atom to form distorted OFe2Bi2 trigonal pyramids that share  a cornercorner with one O(4)MgFeBi2 trigonal pyramid, corners with two equivalent O(1)Fe2Bi2 trigonal pyramids, corners with two equivalent O(3)Fe2Bi2 trigonal pyramids, corners with three equivalent O(5)MgFeBi2 trigonal pyramids, corners with three equivalent O(6)MgFeBi2 trigonal pyramids,  an edgeedge with one O(1)Fe2Bi2 trigonal pyramid,  an edgeedge with one O(3)Fe2Bi2 trigonal pyramid, and  an edgeedge with one O(4)MgFeBi2 trigonal pyramid. In the third O site, O(3) is bonded to one Fe(1), one Fe(2), one Bi(1), and one Bi(2) atom to form distorted OFe2Bi2 trigonal pyramids that share  a cornercorner with one O(5)MgFeBi2 trigonal pyramid, corners with two equivalent O(1)Fe2Bi2 trigonal pyramids, corners with two equivalent O(2)Fe2Bi2 trigonal pyramids, corners with three equivalent O(4)MgFeBi2 trigonal pyramids, corners with three equivalent O(6)MgFeBi2 trigonal pyramids,  an edgeedge with one O(1)Fe2Bi2 trigonal pyramid,  an edgeedge with one O(2)Fe2Bi2 trigonal pyramid, and  an edgeedge with one O(5)MgFeBi2 trigonal pyramid. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(2), one Bi(1), and one Bi(2) atom to form distorted OMgFeBi2 trigonal pyramids that share  a cornercorner with one O(2)Fe2Bi2 trigonal pyramid, corners with two equivalent O(5)MgFeBi2 trigonal pyramids, corners with two equivalent O(6)MgFeBi2 trigonal pyramids, corners with three equivalent O(1)Fe2Bi2 trigonal pyramids, corners with three equivalent O(3)Fe2Bi2 trigonal pyramids,  an edgeedge with one O(2)Fe2Bi2 trigonal pyramid,  an edgeedge with one O(5)MgFeBi2 trigonal pyramid, and  an edgeedge with one O(6)MgFeBi2 trigonal pyramid. In the fifth O site, O(5) is bonded to one Mg(1), one Fe(2), one Bi(1), and one Bi(2) atom to form distorted OMgFeBi2 trigonal pyramids that share  a cornercorner with one O(3)Fe2Bi2 trigonal pyramid, corners with two equivalent O(4)MgFeBi2 trigonal pyramids, corners with two equivalent O(6)MgFeBi2 trigonal pyramids, corners with three equivalent O(1)Fe2Bi2 trigonal pyramids, corners with three equivalent O(2)Fe2Bi2 trigonal pyramids,  an edgeedge with one O(3)Fe2Bi2 trigonal pyramid,  an edgeedge with one O(4)MgFeBi2 trigonal pyramid, and  an edgeedge with one O(6)MgFeBi2 trigonal pyramid. In the sixth O site, O(6) is bonded to one Mg(1), one Fe(2), one Bi(1), and one Bi(2) atom to form distorted OMgFeBi2 trigonal pyramids that share  a cornercorner with one O(1)Fe2Bi2 trigonal pyramid, corners with two equivalent O(4)MgFeBi2 trigonal pyramids, corners with two equivalent O(5)MgFeBi2 trigonal pyramids, corners with three equivalent O(2)Fe2Bi2 trigonal pyramids, corners with three equivalent O(3)Fe2Bi2 trigonal pyramids,  an edgeedge with one O(1)Fe2Bi2 trigonal pyramid,  an edgeedge with one O(4)MgFeBi2 trigonal pyramid, and  an edgeedge with one O(5)MgFeBi2 trigonal pyramid.