BaNdLaMn3O9 crystallizes in the trigonal P321 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to six equivalent O(2) and six equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Mn(2)O6 octahedra, and faces with six equivalent Mn(3)O6 octahedra. In the second Ba site, Ba(2) is bonded to six equivalent O(1) and six equivalent O(4) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(2)O12 cuboctahedra, faces with two equivalent Mn(2)O6 octahedra, and faces with six equivalent Mn(1)O6 octahedra. Nd(1) is bonded in a 9-coordinate geometry to three equivalent O(1), three equivalent O(3), and three equivalent O(4) atoms. La(1) is bonded in a 9-coordinate geometry to three equivalent O(1), three equivalent O(2), and three equivalent O(3) atoms. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form MnO6 octahedra that share corners with three equivalent Mn(1)O6 octahedra, corners with three equivalent Mn(2)O6 octahedra, and faces with three equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 8-22°. In the second Mn site, Mn(2) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form MnO6 octahedra that share corners with three equivalent Mn(1)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, and  a faceface with one Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 20-22°. In the third Mn site, Mn(3) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form MnO6 octahedra that share corners with three equivalent Mn(2)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra, and faces with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 7-20°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Ba(2), one Nd(1), one La(1), one Mn(1), and one Mn(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent Ba(1), two equivalent La(1), and two equivalent Mn(3) atoms. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ba(1), one Nd(1), one La(1), one Mn(2), and one Mn(3) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Ba(2), two equivalent Nd(1), and two equivalent Mn(1) atoms.
BaNdLaMn3O9 crystallizes in the trigonal P321 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to six equivalent O(2) and six equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Mn(2)O6 octahedra, and faces with six equivalent Mn(3)O6 octahedra. There are three shorter (2.69 Å) and three longer (2.94 Å) Ba(1)-O(2) bond lengths. All Ba(1)-O(3) bond lengths are 2.91 Å. In the second Ba site, Ba(2) is bonded to six equivalent O(1) and six equivalent O(4) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(2)O12 cuboctahedra, faces with two equivalent Mn(2)O6 octahedra, and faces with six equivalent Mn(1)O6 octahedra. All Ba(2)-O(1) bond lengths are 2.90 Å. There are three shorter (2.67 Å) and three longer (2.95 Å) Ba(2)-O(4) bond lengths. Nd(1) is bonded in a 9-coordinate geometry to three equivalent O(1), three equivalent O(3), and three equivalent O(4) atoms. All Nd(1)-O(1) bond lengths are 2.44 Å. All Nd(1)-O(3) bond lengths are 2.67 Å. All Nd(1)-O(4) bond lengths are 2.80 Å. La(1) is bonded in a 9-coordinate geometry to three equivalent O(1), three equivalent O(2), and three equivalent O(3) atoms. All La(1)-O(1) bond lengths are 2.69 Å. All La(1)-O(2) bond lengths are 2.80 Å. All La(1)-O(3) bond lengths are 2.48 Å. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form MnO6 octahedra that share corners with three equivalent Mn(1)O6 octahedra, corners with three equivalent Mn(2)O6 octahedra, and faces with three equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 8-22°. All Mn(1)-O(1) bond lengths are 2.03 Å. All Mn(1)-O(4) bond lengths are 1.98 Å. In the second Mn site, Mn(2) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form MnO6 octahedra that share corners with three equivalent Mn(1)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, and  a faceface with one Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 20-22°. All Mn(2)-O(1) bond lengths are 2.00 Å. All Mn(2)-O(3) bond lengths are 1.99 Å. In the third Mn site, Mn(3) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form MnO6 octahedra that share corners with three equivalent Mn(2)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra, and faces with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 7-20°. All Mn(3)-O(2) bond lengths are 1.98 Å. All Mn(3)-O(3) bond lengths are 2.03 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Ba(2), one Nd(1), one La(1), one Mn(1), and one Mn(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent Ba(1), two equivalent La(1), and two equivalent Mn(3) atoms. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ba(1), one Nd(1), one La(1), one Mn(2), and one Mn(3) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to two equivalent Ba(2), two equivalent Nd(1), and two equivalent Mn(1) atoms.