Ba2MnO3 crystallizes in the monoclinic Cc space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms. In the second Ba site, Ba(2) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(4), one O(5), one O(6), and two equivalent O(2) atoms. In the third Ba site, Ba(3) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. In the fourth Ba site, Ba(4) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(1) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form corner-sharing MnO4 tetrahedra. In the second Mn site, Mn(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form corner-sharing MnO4 tetrahedra. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(3), one Ba(4), one Mn(1), and one Mn(2) atom. In the second O site, O(6) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), one Ba(4), two equivalent Ba(1), and one Mn(2) atom. In the third O site, O(1) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(3), two equivalent Ba(4), and one Mn(2) atom. In the fourth O site, O(2) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), one Ba(4), two equivalent Ba(2), and one Mn(1) atom. In the fifth O site, O(3) is bonded in a distorted octahedral geometry to one Ba(1), one Ba(2), one Ba(3), one Ba(4), one Mn(1), and one Mn(2) atom. In the sixth O site, O(4) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(4), two equivalent Ba(3), and one Mn(1) atom.
Ba2MnO3 crystallizes in the monoclinic Cc space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms. The Ba(1)-O(1) bond length is 2.73 Å. The Ba(1)-O(2) bond length is 2.88 Å. The Ba(1)-O(3) bond length is 2.88 Å. The Ba(1)-O(4) bond length is 2.72 Å. The Ba(1)-O(5) bond length is 2.94 Å. There is one shorter (2.70 Å) and one longer (3.33 Å) Ba(1)-O(6) bond length. In the second Ba site, Ba(2) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(4), one O(5), one O(6), and two equivalent O(2) atoms. The Ba(2)-O(1) bond length is 2.69 Å. The Ba(2)-O(3) bond length is 2.95 Å. The Ba(2)-O(4) bond length is 2.71 Å. The Ba(2)-O(5) bond length is 2.95 Å. The Ba(2)-O(6) bond length is 2.88 Å. There is one shorter (2.70 Å) and one longer (3.33 Å) Ba(2)-O(2) bond length. In the third Ba site, Ba(3) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. The Ba(3)-O(1) bond length is 2.77 Å. The Ba(3)-O(2) bond length is 2.71 Å. The Ba(3)-O(3) bond length is 2.79 Å. The Ba(3)-O(5) bond length is 2.94 Å. The Ba(3)-O(6) bond length is 2.78 Å. There is one shorter (2.81 Å) and one longer (3.23 Å) Ba(3)-O(4) bond length. In the fourth Ba site, Ba(4) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(1) atoms. The Ba(4)-O(2) bond length is 2.78 Å. The Ba(4)-O(3) bond length is 2.82 Å. The Ba(4)-O(4) bond length is 2.78 Å. The Ba(4)-O(5) bond length is 2.86 Å. The Ba(4)-O(6) bond length is 2.73 Å. There is one shorter (2.85 Å) and one longer (3.20 Å) Ba(4)-O(1) bond length. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form corner-sharing MnO4 tetrahedra. The Mn(1)-O(2) bond length is 2.03 Å. The Mn(1)-O(3) bond length is 2.07 Å. The Mn(1)-O(4) bond length is 2.04 Å. The Mn(1)-O(5) bond length is 2.04 Å. In the second Mn site, Mn(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form corner-sharing MnO4 tetrahedra. The Mn(2)-O(1) bond length is 2.03 Å. The Mn(2)-O(3) bond length is 2.08 Å. The Mn(2)-O(5) bond length is 2.04 Å. The Mn(2)-O(6) bond length is 2.03 Å. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(3), one Ba(4), one Mn(1), and one Mn(2) atom. In the second O site, O(6) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(3), one Ba(4), two equivalent Ba(1), and one Mn(2) atom. In the third O site, O(1) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(3), two equivalent Ba(4), and one Mn(2) atom. In the fourth O site, O(2) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(3), one Ba(4), two equivalent Ba(2), and one Mn(1) atom. In the fifth O site, O(3) is bonded in a distorted octahedral geometry to one Ba(1), one Ba(2), one Ba(3), one Ba(4), one Mn(1), and one Mn(2) atom. In the sixth O site, O(4) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(4), two equivalent Ba(3), and one Mn(1) atom.