MgCr2(FeO3)2 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Cr(1)O6 octahedra and faces with two equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-40°. Cr(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CrO6 octahedra that share corners with three equivalent Mg(1)O6 octahedra, edges with three equivalent Cr(1)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-40°. Fe(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), two equivalent Cr(1), and two equivalent Fe(1) atoms to form a mixture of distorted edge and corner-sharing OMgCr2Fe2 trigonal bipyramids. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent Cr(1), and two equivalent Fe(1) atoms. In the third O site, O(3) is bonded to one Mg(1), two equivalent Cr(1), and two equivalent Fe(1) atoms to form a mixture of distorted edge and corner-sharing OMgCr2Fe2 trigonal bipyramids.
MgCr2(FeO3)2 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Cr(1)O6 octahedra and faces with two equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-40°. Both Mg(1)-O(1) bond lengths are 2.06 Å. Both Mg(1)-O(2) bond lengths are 2.08 Å. Both Mg(1)-O(3) bond lengths are 2.08 Å. Cr(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CrO6 octahedra that share corners with three equivalent Mg(1)O6 octahedra, edges with three equivalent Cr(1)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-40°. There is one shorter (2.01 Å) and one longer (2.09 Å) Cr(1)-O(1) bond length. There is one shorter (2.01 Å) and one longer (2.08 Å) Cr(1)-O(2) bond length. There is one shorter (2.01 Å) and one longer (2.10 Å) Cr(1)-O(3) bond length. Fe(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. There is one shorter (2.10 Å) and one longer (2.38 Å) Fe(1)-O(1) bond length. There is one shorter (2.07 Å) and one longer (2.43 Å) Fe(1)-O(2) bond length. There is one shorter (2.08 Å) and one longer (2.37 Å) Fe(1)-O(3) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), two equivalent Cr(1), and two equivalent Fe(1) atoms to form a mixture of distorted edge and corner-sharing OMgCr2Fe2 trigonal bipyramids. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent Cr(1), and two equivalent Fe(1) atoms. In the third O site, O(3) is bonded to one Mg(1), two equivalent Cr(1), and two equivalent Fe(1) atoms to form a mixture of distorted edge and corner-sharing OMgCr2Fe2 trigonal bipyramids.