MgMnSbO4 crystallizes in the orthorhombic Imm2 space group. Mg(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra,  a cornercorner with one Mn(1)O5 trigonal bipyramid, edges with four equivalent Sb(1)O6 octahedra, and edges with four equivalent Mn(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 11-18°. Mn(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(3) atoms to form MnO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Sb(1)O6 octahedra, corners with four equivalent Mn(1)O5 trigonal bipyramids, edges with two equivalent Sb(1)O6 octahedra, and edges with four equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-72°. Sb(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form SbO6 octahedra that share corners with four equivalent Sb(1)O6 octahedra, corners with two equivalent Mn(1)O5 trigonal bipyramids, edges with four equivalent Mg(1)O6 octahedra, and edges with two equivalent Mn(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-20°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), two equivalent Mn(1), and one Sb(1) atom to form a mixture of corner and edge-sharing OMg2Mn2Sb trigonal bipyramids. In the second O site, O(2) is bonded in a T-shaped geometry to one Mg(1) and two equivalent Sb(1) atoms. In the third O site, O(3) is bonded to two equivalent Mg(1), two equivalent Mn(1), and one Sb(1) atom to form a mixture of corner and edge-sharing OMg2Mn2Sb square pyramids. In the fourth O site, O(4) is bonded in a square co-planar geometry to one Mg(1), one Mn(1), and two equivalent Sb(1) atoms.
MgMnSbO4 crystallizes in the orthorhombic Imm2 space group. Mg(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra,  a cornercorner with one Mn(1)O5 trigonal bipyramid, edges with four equivalent Sb(1)O6 octahedra, and edges with four equivalent Mn(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 11-18°. The Mg(1)-O(2) bond length is 2.22 Å. The Mg(1)-O(4) bond length is 2.25 Å. Both Mg(1)-O(1) bond lengths are 2.19 Å. Both Mg(1)-O(3) bond lengths are 2.10 Å. Mn(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(3) atoms to form MnO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Sb(1)O6 octahedra, corners with four equivalent Mn(1)O5 trigonal bipyramids, edges with two equivalent Sb(1)O6 octahedra, and edges with four equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-72°. The Mn(1)-O(4) bond length is 2.24 Å. Both Mn(1)-O(1) bond lengths are 2.17 Å. Both Mn(1)-O(3) bond lengths are 2.19 Å. Sb(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form SbO6 octahedra that share corners with four equivalent Sb(1)O6 octahedra, corners with two equivalent Mn(1)O5 trigonal bipyramids, edges with four equivalent Mg(1)O6 octahedra, and edges with two equivalent Mn(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-20°. The Sb(1)-O(1) bond length is 2.14 Å. The Sb(1)-O(3) bond length is 2.25 Å. Both Sb(1)-O(2) bond lengths are 2.10 Å. Both Sb(1)-O(4) bond lengths are 2.18 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), two equivalent Mn(1), and one Sb(1) atom to form a mixture of corner and edge-sharing OMg2Mn2Sb trigonal bipyramids. In the second O site, O(2) is bonded in a T-shaped geometry to one Mg(1) and two equivalent Sb(1) atoms. In the third O site, O(3) is bonded to two equivalent Mg(1), two equivalent Mn(1), and one Sb(1) atom to form a mixture of corner and edge-sharing OMg2Mn2Sb square pyramids. In the fourth O site, O(4) is bonded in a square co-planar geometry to one Mg(1), one Mn(1), and two equivalent Sb(1) atoms.