MgCr2Mn2O8 crystallizes in the orthorhombic Amm2 space group. Mg(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form distorted MgO4 tetrahedra that share corners with six equivalent Mn(1)O6 octahedra, corners with two equivalent Cr(2)O4 tetrahedra, and  an edgeedge with one Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 66-68°. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form CrO4 tetrahedra that share corners with six equivalent Mn(1)O6 octahedra and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-58°. In the second Cr site, Cr(2) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form CrO4 tetrahedra that share corners with six equivalent Mn(1)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. Mn(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Cr(1)O4 tetrahedra, corners with three equivalent Cr(2)O4 tetrahedra, and edges with two equivalent Mn(1)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one Mn(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mg(1), one Cr(2), and one Mn(1) atom. In the third O site, O(3) is bonded to one Mg(1), one Cr(1), and two equivalent Mn(1) atoms to form distorted edge-sharing OMgMn2Cr tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cr(2) and two equivalent Mn(1) atoms.
MgCr2Mn2O8 crystallizes in the orthorhombic Amm2 space group. Mg(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form distorted MgO4 tetrahedra that share corners with six equivalent Mn(1)O6 octahedra, corners with two equivalent Cr(2)O4 tetrahedra, and  an edgeedge with one Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 66-68°. Both Mg(1)-O(2) bond lengths are 1.98 Å. Both Mg(1)-O(3) bond lengths are 2.04 Å. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form CrO4 tetrahedra that share corners with six equivalent Mn(1)O6 octahedra and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-58°. Both Cr(1)-O(1) bond lengths are 1.66 Å. Both Cr(1)-O(3) bond lengths are 1.85 Å. In the second Cr site, Cr(2) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form CrO4 tetrahedra that share corners with six equivalent Mn(1)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. Both Cr(2)-O(2) bond lengths are 1.78 Å. Both Cr(2)-O(4) bond lengths are 1.73 Å. Mn(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Cr(1)O4 tetrahedra, corners with three equivalent Cr(2)O4 tetrahedra, and edges with two equivalent Mn(1)O6 octahedra. The Mn(1)-O(1) bond length is 2.13 Å. The Mn(1)-O(2) bond length is 2.13 Å. Both Mn(1)-O(3) bond lengths are 2.25 Å. Both Mn(1)-O(4) bond lengths are 2.15 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one Mn(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mg(1), one Cr(2), and one Mn(1) atom. In the third O site, O(3) is bonded to one Mg(1), one Cr(1), and two equivalent Mn(1) atoms to form distorted edge-sharing OMgMn2Cr tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cr(2) and two equivalent Mn(1) atoms.