Ba3Mn2IrO9 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal R-3m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ir(1)O6 octahedra, faces with eight equivalent Ba(2)O12 cuboctahedra, and faces with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 15°. In the second Ba site, Ba(2) is bonded to three equivalent O(2) and nine equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with nine equivalent Ba(2)O12 cuboctahedra, corners with three equivalent Mn(1)O6 octahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ir(1)O6 octahedra, and faces with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 9°. Mn(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form MnO6 octahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with three equivalent Mn(1)O6 octahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(2)O12 cuboctahedra, and  a faceface with one Ir(1)O6 octahedra. The corner-sharing octahedra are not tilted. Ir(1) is bonded to six equivalent O(1) atoms to form IrO6 octahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, faces with six equivalent Ba(2)O12 cuboctahedra, and faces with two equivalent Mn(1)O6 octahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), three equivalent Ba(2), one Mn(1), and one Ir(1) atom to form a mixture of distorted face, corner, and edge-sharing OBa4MnIr octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Mn(1) atoms.
Ba3Mn2IrO9 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal R-3m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ir(1)O6 octahedra, faces with eight equivalent Ba(2)O12 cuboctahedra, and faces with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 15°. All Ba(1)-O(1) bond lengths are 3.05 Å. All Ba(1)-O(2) bond lengths are 2.92 Å. In the second Ba site, Ba(2) is bonded to three equivalent O(2) and nine equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with nine equivalent Ba(2)O12 cuboctahedra, corners with three equivalent Mn(1)O6 octahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ir(1)O6 octahedra, and faces with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 9°. All Ba(2)-O(2) bond lengths are 3.01 Å. There are six shorter (2.92 Å) and three longer (3.02 Å) Ba(2)-O(1) bond lengths. Mn(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form MnO6 octahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with three equivalent Mn(1)O6 octahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(2)O12 cuboctahedra, and  a faceface with one Ir(1)O6 octahedra. The corner-sharing octahedra are not tilted. All Mn(1)-O(1) bond lengths are 2.13 Å. All Mn(1)-O(2) bond lengths are 1.95 Å. Ir(1) is bonded to six equivalent O(1) atoms to form IrO6 octahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, faces with six equivalent Ba(2)O12 cuboctahedra, and faces with two equivalent Mn(1)O6 octahedra. All Ir(1)-O(1) bond lengths are 1.98 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), three equivalent Ba(2), one Mn(1), and one Ir(1) atom to form a mixture of distorted face, corner, and edge-sharing OBa4MnIr octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Mn(1) atoms.