MgMn3SnO8 crystallizes in the trigonal R-3m space group. Mg(1) is bonded to six equivalent O(2) atoms to form MgO6 octahedra that share corners with six equivalent Sn(1)O6 octahedra and edges with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 8°. Mn(1) 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 Sn(1)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. Sn(1) is bonded to six equivalent O(2) atoms to form SnO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra and edges with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Mn(1), and one Sn(1) atom.
MgMn3SnO8 crystallizes in the trigonal R-3m space group. Mg(1) is bonded to six equivalent O(2) atoms to form MgO6 octahedra that share corners with six equivalent Sn(1)O6 octahedra and edges with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 8°. All Mg(1)-O(2) bond lengths are 2.17 Å. Mn(1) 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 Sn(1)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. Both Mn(1)-O(1) bond lengths are 1.96 Å. All Mn(1)-O(2) bond lengths are 2.05 Å. Sn(1) is bonded to six equivalent O(2) atoms to form SnO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra and edges with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 8°. All Sn(1)-O(2) bond lengths are 2.13 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Mn(1), and one Sn(1) atom.