Ba3MnO5 crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a distorted q6 geometry to two equivalent O(1) and eight equivalent O(2) atoms. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to two equivalent O(1) and six equivalent O(2) atoms. Mn(1) is bonded in a tetrahedral geometry to four equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1) and four equivalent Ba(2) atoms to form corner-sharing OBa6 octahedra. The corner-sharing octahedral tilt angles range from 0-32°. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Ba(1), three equivalent Ba(2), and one Mn(1) atom.
Ba3MnO5 crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a distorted q6 geometry to two equivalent O(1) and eight equivalent O(2) atoms. Both Ba(1)-O(1) bond lengths are 3.03 Å. All Ba(1)-O(2) bond lengths are 3.11 Å. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to two equivalent O(1) and six equivalent O(2) atoms. Both Ba(2)-O(1) bond lengths are 2.70 Å. There are two shorter (2.70 Å) and four longer (2.94 Å) Ba(2)-O(2) bond lengths. Mn(1) is bonded in a tetrahedral geometry to four equivalent O(2) atoms. All Mn(1)-O(2) bond lengths are 1.81 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1) and four equivalent Ba(2) atoms to form corner-sharing OBa6 octahedra. The corner-sharing octahedral tilt angles range from 0-32°. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Ba(1), three equivalent Ba(2), and one Mn(1) atom.