Ba3NdRu2O9 crystallizes in the monoclinic C2/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(4), two equivalent O(5), three equivalent O(1), three equivalent O(2), and three equivalent O(3) atoms to form distorted BaO12 cuboctahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with six equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Ru(1)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 Ru(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-15°. In the second Ba site, Ba(2) is bonded to two equivalent O(1), two equivalent O(2), two equivalent O(3), two equivalent O(4), and four equivalent O(5) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ba(2)O12 cuboctahedra, faces with six equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Nd(1)O6 octahedra, and faces with six equivalent Ru(1)O6 octahedra. Nd(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NdO6 octahedra that share corners with six equivalent Ru(1)O6 octahedra, faces with two equivalent Ba(2)O12 cuboctahedra, and faces with six equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-6°. Ru(1) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form RuO6 octahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Nd(1)O6 octahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, and  a faceface with one Ru(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-6°. There are five inequivalent O sites. In the first O site, O(3) is bonded in a distorted linear geometry to one Ba(2), three equivalent Ba(1), one Nd(1), and one Ru(1) atom. In the second O site, O(4) is bonded to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Ru(1) atoms to form a mixture of distorted corner and face-sharing OBa4Ru2 octahedra. The corner-sharing octahedral tilt angles range from 4-60°. In the third O site, O(5) is bonded to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Ru(1) atoms to form a mixture of distorted corner and face-sharing OBa4Ru2 octahedra. The corner-sharing octahedral tilt angles range from 4-60°. In the fourth O site, O(1) is bonded in a 2-coordinate geometry to one Ba(2), three equivalent Ba(1), one Nd(1), and one Ru(1) atom. In the fifth O site, O(2) is bonded in a distorted linear geometry to one Ba(2), three equivalent Ba(1), one Nd(1), and one Ru(1) atom.
Ba3NdRu2O9 crystallizes in the monoclinic C2/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(4), two equivalent O(5), three equivalent O(1), three equivalent O(2), and three equivalent O(3) atoms to form distorted BaO12 cuboctahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with six equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Ru(1)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 Ru(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-15°. The Ba(1)-O(4) bond length is 2.86 Å. There is one shorter (2.81 Å) and one longer (2.93 Å) Ba(1)-O(5) bond length. There are a spread of Ba(1)-O(1) bond distances ranging from 2.97-3.39 Å. There are a spread of Ba(1)-O(2) bond distances ranging from 2.99-3.23 Å. There are a spread of Ba(1)-O(3) bond distances ranging from 2.95-3.34 Å. In the second Ba site, Ba(2) is bonded to two equivalent O(1), two equivalent O(2), two equivalent O(3), two equivalent O(4), and four equivalent O(5) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ba(2)O12 cuboctahedra, faces with six equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Nd(1)O6 octahedra, and faces with six equivalent Ru(1)O6 octahedra. Both Ba(2)-O(1) bond lengths are 2.90 Å. Both Ba(2)-O(2) bond lengths are 3.11 Å. Both Ba(2)-O(3) bond lengths are 2.98 Å. Both Ba(2)-O(4) bond lengths are 3.01 Å. There are two shorter (3.00 Å) and two longer (3.01 Å) Ba(2)-O(5) bond lengths. Nd(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NdO6 octahedra that share corners with six equivalent Ru(1)O6 octahedra, faces with two equivalent Ba(2)O12 cuboctahedra, and faces with six equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-6°. Both Nd(1)-O(1) bond lengths are 2.31 Å. Both Nd(1)-O(2) bond lengths are 2.32 Å. Both Nd(1)-O(3) bond lengths are 2.31 Å. Ru(1) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form RuO6 octahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Nd(1)O6 octahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, and  a faceface with one Ru(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-6°. The Ru(1)-O(1) bond length is 1.96 Å. The Ru(1)-O(2) bond length is 1.95 Å. The Ru(1)-O(3) bond length is 1.96 Å. The Ru(1)-O(4) bond length is 2.06 Å. Both Ru(1)-O(5) bond lengths are 2.06 Å. There are five inequivalent O sites. In the first O site, O(3) is bonded in a distorted linear geometry to one Ba(2), three equivalent Ba(1), one Nd(1), and one Ru(1) atom. In the second O site, O(4) is bonded to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Ru(1) atoms to form a mixture of distorted corner and face-sharing OBa4Ru2 octahedra. The corner-sharing octahedral tilt angles range from 4-60°. In the third O site, O(5) is bonded to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Ru(1) atoms to form a mixture of distorted corner and face-sharing OBa4Ru2 octahedra. The corner-sharing octahedral tilt angles range from 4-60°. In the fourth O site, O(1) is bonded in a 2-coordinate geometry to one Ba(2), three equivalent Ba(1), one Nd(1), and one Ru(1) atom. In the fifth O site, O(2) is bonded in a distorted linear geometry to one Ba(2), three equivalent Ba(1), one Nd(1), and one Ru(1) atom.