BaMn5O11 crystallizes in the monoclinic Cm space group. Ba(1) is bonded in a 10-coordinate geometry to one O(2), one O(9), two equivalent O(1), two equivalent O(11), two equivalent O(5), and two equivalent O(7) atoms. There are five inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(3), two equivalent O(5), and two equivalent O(9) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 52-53°. In the second Mn site, Mn(2) is bonded to one O(2), one O(4), two equivalent O(10), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 52°. In the third Mn site, Mn(3) is bonded to one O(8), one O(9), two equivalent O(4), and two equivalent O(7) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 52-53°. In the fourth Mn site, Mn(4) is bonded to one O(10), one O(7), two equivalent O(3), and two equivalent O(8) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 52°. In the fifth Mn site, Mn(5) is bonded to one O(5), one O(6), two equivalent O(1), and two equivalent O(2) atoms to form edge-sharing MnO6 octahedra. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Mn(1), and two equivalent Mn(5) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ba(1), one Mn(2), and two equivalent Mn(5) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mn(1) and two equivalent Mn(4) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Mn(2) and two equivalent Mn(3) atoms. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Mn(5), and two equivalent Mn(1) atoms. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Mn(5) and two equivalent Mn(2) atoms. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Mn(4), and two equivalent Mn(3) atoms. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Mn(3) and two equivalent Mn(4) atoms. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Ba(1), one Mn(3), and two equivalent Mn(1) atoms. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Mn(4) and two equivalent Mn(2) atoms. In the eleventh O site, O(11) is bonded in a distorted L-shaped geometry to two equivalent Ba(1) atoms.
BaMn5O11 crystallizes in the monoclinic Cm space group. Ba(1) is bonded in a 10-coordinate geometry to one O(2), one O(9), two equivalent O(1), two equivalent O(11), two equivalent O(5), and two equivalent O(7) atoms. The Ba(1)-O(2) bond length is 3.07 Å. The Ba(1)-O(9) bond length is 3.12 Å. Both Ba(1)-O(1) bond lengths are 2.91 Å. Both Ba(1)-O(11) bond lengths are 2.49 Å. Both Ba(1)-O(5) bond lengths are 2.88 Å. Both Ba(1)-O(7) bond lengths are 3.08 Å. There are five inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(3), two equivalent O(5), and two equivalent O(9) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 52-53°. The Mn(1)-O(1) bond length is 1.98 Å. The Mn(1)-O(3) bond length is 1.92 Å. Both Mn(1)-O(5) bond lengths are 2.08 Å. Both Mn(1)-O(9) bond lengths are 2.00 Å. In the second Mn site, Mn(2) is bonded to one O(2), one O(4), two equivalent O(10), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 52°. The Mn(2)-O(2) bond length is 2.00 Å. The Mn(2)-O(4) bond length is 1.94 Å. Both Mn(2)-O(10) bond lengths are 1.96 Å. Both Mn(2)-O(6) bond lengths are 1.98 Å. In the third Mn site, Mn(3) is bonded to one O(8), one O(9), two equivalent O(4), and two equivalent O(7) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 52-53°. The Mn(3)-O(8) bond length is 1.91 Å. The Mn(3)-O(9) bond length is 1.87 Å. Both Mn(3)-O(4) bond lengths are 1.92 Å. Both Mn(3)-O(7) bond lengths are 2.01 Å. In the fourth Mn site, Mn(4) is bonded to one O(10), one O(7), two equivalent O(3), and two equivalent O(8) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 52°. The Mn(4)-O(10) bond length is 1.88 Å. The Mn(4)-O(7) bond length is 1.94 Å. Both Mn(4)-O(3) bond lengths are 1.94 Å. Both Mn(4)-O(8) bond lengths are 1.95 Å. In the fifth Mn site, Mn(5) is bonded to one O(5), one O(6), two equivalent O(1), and two equivalent O(2) atoms to form edge-sharing MnO6 octahedra. The Mn(5)-O(5) bond length is 1.94 Å. The Mn(5)-O(6) bond length is 1.92 Å. Both Mn(5)-O(1) bond lengths are 2.04 Å. Both Mn(5)-O(2) bond lengths are 1.97 Å. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Mn(1), and two equivalent Mn(5) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ba(1), one Mn(2), and two equivalent Mn(5) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mn(1) and two equivalent Mn(4) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Mn(2) and two equivalent Mn(3) atoms. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Mn(5), and two equivalent Mn(1) atoms. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Mn(5) and two equivalent Mn(2) atoms. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to two equivalent Ba(1), one Mn(4), and two equivalent Mn(3) atoms. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Mn(3) and two equivalent Mn(4) atoms. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Ba(1), one Mn(3), and two equivalent Mn(1) atoms. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Mn(4) and two equivalent Mn(2) atoms. In the eleventh O site, O(11) is bonded in a distorted L-shaped geometry to two equivalent Ba(1) atoms.