MgMn3TeO8 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form MgO6 octahedra that share corners with six equivalent Te(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-11°. There are two inequivalent Mn sites. In the first Mn site, Mn(1) 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 Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Te(1)O6 octahedra. In the second Mn site, Mn(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form MnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Te(1)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. Te(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form TeO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-11°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to one Mn(2) and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(1), one Mn(2), and one Te(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Mn(1), and one Te(1) atom.
MgMn3TeO8 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form MgO6 octahedra that share corners with six equivalent Te(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-11°. Both Mg(1)-O(3) bond lengths are 2.36 Å. All Mg(1)-O(2) bond lengths are 2.10 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) 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 Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Te(1)O6 octahedra. Both Mn(1)-O(1) bond lengths are 2.00 Å. Both Mn(1)-O(2) bond lengths are 2.26 Å. Both Mn(1)-O(3) bond lengths are 1.98 Å. In the second Mn site, Mn(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form MnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Te(1)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. Both Mn(2)-O(1) bond lengths are 1.98 Å. All Mn(2)-O(2) bond lengths are 1.94 Å. Te(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form TeO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-11°. Both Te(1)-O(3) bond lengths are 2.24 Å. All Te(1)-O(2) bond lengths are 2.18 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to one Mn(2) and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(1), one Mn(2), and one Te(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Mn(1), and one Te(1) atom.