MgCr2O4 crystallizes in the monoclinic Pm space group. Mg(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), and two equivalent O(4) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form edge-sharing CrO6 octahedra. In the second Cr site, Cr(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(2) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Cr(1), and two equivalent Cr(2) atoms to form corner-sharing OMgCr3 trigonal pyramids. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(1), and two equivalent Cr(2) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Cr(2) and two equivalent Cr(1) atoms. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Cr(1) atoms.
MgCr2O4 crystallizes in the monoclinic Pm space group. Mg(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), and two equivalent O(4) atoms. The Mg(1)-O(1) bond length is 2.07 Å. The Mg(1)-O(2) bond length is 2.09 Å. Both Mg(1)-O(4) bond lengths are 1.97 Å. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form edge-sharing CrO6 octahedra. The Cr(1)-O(1) bond length is 2.04 Å. The Cr(1)-O(2) bond length is 2.00 Å. Both Cr(1)-O(3) bond lengths are 2.03 Å. Both Cr(1)-O(4) bond lengths are 2.07 Å. In the second Cr site, Cr(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(2) atoms. The Cr(2)-O(3) bond length is 1.96 Å. Both Cr(2)-O(1) bond lengths are 2.02 Å. Both Cr(2)-O(2) bond lengths are 2.06 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Cr(1), and two equivalent Cr(2) atoms to form corner-sharing OMgCr3 trigonal pyramids. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(1), and two equivalent Cr(2) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Cr(2) and two equivalent Cr(1) atoms. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Cr(1) atoms.