BaMgMnO3 crystallizes in the monoclinic Cm space group. Ba(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Mg(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO5 trigonal bipyramids that share  a cornercorner with one Mn(1)O5 trigonal bipyramid, corners with four equivalent Mg(1)O5 trigonal bipyramids, and edges with four equivalent Mn(1)O5 trigonal bipyramids. Mn(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O5 trigonal bipyramid, corners with four equivalent Mn(1)O5 trigonal bipyramids, and edges with four equivalent Mg(1)O5 trigonal bipyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1), one Mg(1), and one Mn(1) atom to form distorted OBa4MgMn octahedra that share corners with four equivalent O(1)Ba4MgMn octahedra, corners with six equivalent O(2)Ba2Mg2Mn2 octahedra, edges with four equivalent O(1)Ba4MgMn octahedra, and faces with two equivalent O(2)Ba2Mg2Mn2 octahedra. The corner-sharing octahedral tilt angles range from 1-65°. In the second O site, O(2) is bonded to two equivalent Ba(1), two equivalent Mg(1), and two equivalent Mn(1) atoms to form distorted OBa2Mg2Mn2 octahedra that share corners with two equivalent O(2)Ba2Mg2Mn2 octahedra, corners with six equivalent O(1)Ba4MgMn octahedra, edges with two equivalent O(2)Ba2Mg2Mn2 octahedra, and faces with two equivalent O(1)Ba4MgMn octahedra. The corner-sharing octahedral tilt angles range from 8-65°. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Mg(1), and two equivalent Mn(1) atoms.
BaMgMnO3 crystallizes in the monoclinic Cm space group. Ba(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. There is one shorter (2.84 Å) and one longer (2.86 Å) Ba(1)-O(2) bond length. There is one shorter (3.04 Å) and one longer (3.11 Å) Ba(1)-O(3) bond length. There are two shorter (2.82 Å) and two longer (2.83 Å) Ba(1)-O(1) bond lengths. Mg(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO5 trigonal bipyramids that share  a cornercorner with one Mn(1)O5 trigonal bipyramid, corners with four equivalent Mg(1)O5 trigonal bipyramids, and edges with four equivalent Mn(1)O5 trigonal bipyramids. The Mg(1)-O(1) bond length is 2.04 Å. Both Mg(1)-O(2) bond lengths are 2.16 Å. There is one shorter (2.07 Å) and one longer (2.08 Å) Mg(1)-O(3) bond length. Mn(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O5 trigonal bipyramid, corners with four equivalent Mn(1)O5 trigonal bipyramids, and edges with four equivalent Mg(1)O5 trigonal bipyramids. The Mn(1)-O(1) bond length is 2.11 Å. There is one shorter (2.17 Å) and one longer (2.18 Å) Mn(1)-O(2) bond length. Both Mn(1)-O(3) bond lengths are 2.18 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1), one Mg(1), and one Mn(1) atom to form distorted OBa4MgMn octahedra that share corners with four equivalent O(1)Ba4MgMn octahedra, corners with six equivalent O(2)Ba2Mg2Mn2 octahedra, edges with four equivalent O(1)Ba4MgMn octahedra, and faces with two equivalent O(2)Ba2Mg2Mn2 octahedra. The corner-sharing octahedral tilt angles range from 1-65°. In the second O site, O(2) is bonded to two equivalent Ba(1), two equivalent Mg(1), and two equivalent Mn(1) atoms to form distorted OBa2Mg2Mn2 octahedra that share corners with two equivalent O(2)Ba2Mg2Mn2 octahedra, corners with six equivalent O(1)Ba4MgMn octahedra, edges with two equivalent O(2)Ba2Mg2Mn2 octahedra, and faces with two equivalent O(1)Ba4MgMn octahedra. The corner-sharing octahedral tilt angles range from 8-65°. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Mg(1), and two equivalent Mn(1) atoms.