Ba4NdMn3O12 crystallizes in the trigonal R-3m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to three equivalent O(1) and nine equivalent O(2) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with six equivalent Ba(1)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,  a faceface with one Nd(1)O6 octahedra, faces with three equivalent Mn(1)O6 octahedra, and faces with three equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles are 8°. In the second Ba site, Ba(2) is bonded to three equivalent O(2) and nine equivalent O(1) atoms to form distorted BaO12 cuboctahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ba(2)O12 cuboctahedra, corners with three equivalent Mn(2)O6 octahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Nd(1)O6 octahedra, and faces with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 9°. Nd(1) is bonded to six equivalent O(1) atoms to form NdO6 octahedra that share corners with six equivalent Mn(1)O6 octahedra, faces with two equivalent Ba(1)O12 cuboctahedra, and faces with six equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 5°. There are two inequivalent Mn sites. In the first Mn site, 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(1)O12 cuboctahedra, corners with three equivalent Nd(1)O6 octahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(2)O12 cuboctahedra, and  a faceface with one Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles are 5°. In the second Mn site, Mn(2) is bonded to six equivalent O(2) atoms to form MnO6 octahedra that share corners with six equivalent Ba(2)O12 cuboctahedra, faces with six equivalent Ba(1)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 in a 2-coordinate geometry to one Ba(1), three equivalent Ba(2), one Nd(1), and one Mn(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(2), three equivalent Ba(1), one Mn(1), and one Mn(2) atom.
Ba4NdMn3O12 crystallizes in the trigonal R-3m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to three equivalent O(1) and nine equivalent O(2) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with six equivalent Ba(1)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,  a faceface with one Nd(1)O6 octahedra, faces with three equivalent Mn(1)O6 octahedra, and faces with three equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles are 8°. All Ba(1)-O(1) bond lengths are 3.09 Å. There are six shorter (2.97 Å) and three longer (2.99 Å) Ba(1)-O(2) bond lengths. In the second Ba site, Ba(2) is bonded to three equivalent O(2) and nine equivalent O(1) atoms to form distorted BaO12 cuboctahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ba(2)O12 cuboctahedra, corners with three equivalent Mn(2)O6 octahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Nd(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 2.87 Å. There are six shorter (2.97 Å) and three longer (3.39 Å) Ba(2)-O(1) bond lengths. Nd(1) is bonded to six equivalent O(1) atoms to form NdO6 octahedra that share corners with six equivalent Mn(1)O6 octahedra, faces with two equivalent Ba(1)O12 cuboctahedra, and faces with six equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 5°. All Nd(1)-O(1) bond lengths are 2.31 Å. There are two inequivalent Mn sites. In the first Mn site, 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(1)O12 cuboctahedra, corners with three equivalent Nd(1)O6 octahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(2)O12 cuboctahedra, and  a faceface with one Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles are 5°. All Mn(1)-O(1) bond lengths are 1.87 Å. All Mn(1)-O(2) bond lengths are 2.02 Å. In the second Mn site, Mn(2) is bonded to six equivalent O(2) atoms to form MnO6 octahedra that share corners with six equivalent Ba(2)O12 cuboctahedra, faces with six equivalent Ba(1)O12 cuboctahedra, and faces with two equivalent Mn(1)O6 octahedra. All Mn(2)-O(2) bond lengths are 1.94 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), three equivalent Ba(2), one Nd(1), and one Mn(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(2), three equivalent Ba(1), one Mn(1), and one Mn(2) atom.