MgFe2(BO3)2 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to four equivalent O(1) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form face-sharing FeO6 octahedra. In the second Fe site, Fe(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form face-sharing FeO6 octahedra. B(1) is bonded in a trigonal planar geometry to one O(2) and two equivalent O(1) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(2), and one B(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one B(1) atom.
MgFe2(BO3)2 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to four equivalent O(1) atoms. All Mg(1)-O(1) bond lengths are 2.01 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form face-sharing FeO6 octahedra. Both Fe(1)-O(2) bond lengths are 2.03 Å. All Fe(1)-O(1) bond lengths are 2.24 Å. In the second Fe site, Fe(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form face-sharing FeO6 octahedra. Both Fe(2)-O(2) bond lengths are 2.09 Å. All Fe(2)-O(1) bond lengths are 2.24 Å. B(1) is bonded in a trigonal planar geometry to one O(2) and two equivalent O(1) atoms. The B(1)-O(2) bond length is 1.36 Å. Both B(1)-O(1) bond lengths are 1.41 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(2), and one B(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one B(1) atom.