MgCrMn3O8 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with six equivalent Cr(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles are 11°. Cr(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles are 11°. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Cr(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. In the second Mn site, Mn(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Cr(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. In the third Mn site, Mn(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Cr(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with two equivalent Mn(2)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Mn(1), one Mn(2), and one Mn(3) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(1), one Mn(2), and one Mn(3) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(1), one Mn(1), and one Mn(3) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(1), one Mn(1), and one Mn(2) atom.
MgCrMn3O8 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with six equivalent Cr(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles are 11°. Both Mg(1)-O(2) bond lengths are 2.17 Å. Both Mg(1)-O(3) bond lengths are 2.09 Å. Both Mg(1)-O(4) bond lengths are 2.21 Å. Cr(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles are 11°. Both Cr(1)-O(2) bond lengths are 2.07 Å. Both Cr(1)-O(3) bond lengths are 2.04 Å. Both Cr(1)-O(4) bond lengths are 2.08 Å. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Cr(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. Both Mn(1)-O(1) bond lengths are 2.02 Å. Both Mn(1)-O(3) bond lengths are 2.15 Å. Both Mn(1)-O(4) bond lengths are 1.95 Å. In the second Mn site, Mn(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Cr(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. Both Mn(2)-O(1) bond lengths are 1.94 Å. Both Mn(2)-O(2) bond lengths are 1.96 Å. Both Mn(2)-O(4) bond lengths are 1.95 Å. In the third Mn site, Mn(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Cr(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with two equivalent Mn(2)O6 octahedra. Both Mn(3)-O(1) bond lengths are 1.96 Å. Both Mn(3)-O(2) bond lengths are 1.96 Å. Both Mn(3)-O(3) bond lengths are 1.92 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Mn(1), one Mn(2), and one Mn(3) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(1), one Mn(2), and one Mn(3) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(1), one Mn(1), and one Mn(3) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(1), one Mn(1), and one Mn(2) atom.