Ba12V4O19 crystallizes in the monoclinic C2/m space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one O(7), two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to one O(5), one O(6), two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to one O(5), one O(7), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the fourth Ba site, Ba(4) is bonded to one O(6), two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form distorted BaO7 pentagonal bipyramids that share  a cornercorner with one Ba(4)O7 pentagonal bipyramid, corners with two equivalent V(1)O4 tetrahedra, edges with two equivalent Ba(6)O7 pentagonal bipyramids, and edges with two equivalent V(1)O4 tetrahedra. In the fifth Ba site, Ba(5) is bonded in a 8-coordinate geometry to one O(5), one O(6), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. In the sixth Ba site, Ba(6) is bonded to one O(7), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted BaO7 pentagonal bipyramids that share  a cornercorner with one Ba(6)O7 pentagonal bipyramid, corners with two equivalent V(1)O4 tetrahedra, edges with two equivalent Ba(4)O7 pentagonal bipyramids, and edges with two equivalent V(1)O4 tetrahedra. V(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form VO4 tetrahedra that share  a cornercorner with one Ba(4)O7 pentagonal bipyramid,  a cornercorner with one Ba(6)O7 pentagonal bipyramid,  an edgeedge with one Ba(4)O7 pentagonal bipyramid, and  an edgeedge with one Ba(6)O7 pentagonal bipyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(4), one Ba(5), one Ba(6), and one V(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(3), one Ba(5), one Ba(6), and one V(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Ba(3), one Ba(4), one Ba(6), two equivalent Ba(1), and one V(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Ba(3), one Ba(4), one Ba(5), two equivalent Ba(2), and one V(1) atom. In the fifth O site, O(5) is bonded to two equivalent Ba(2), two equivalent Ba(3), and two equivalent Ba(5) atoms to form corner-sharing OBa6 octahedra. The corner-sharing octahedral tilt angles range from 0-33°. In the sixth O site, O(6) is bonded to two equivalent Ba(2), two equivalent Ba(4), and two equivalent Ba(5) atoms to form corner-sharing OBa6 octahedra. The corner-sharing octahedral tilt angles range from 0-33°. In the seventh O site, O(7) is bonded to two equivalent Ba(1), two equivalent Ba(3), and two equivalent Ba(6) atoms to form corner-sharing OBa6 octahedra. The corner-sharing octahedral tilt angles are 33°.
Ba12V4O19 crystallizes in the monoclinic C2/m space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one O(7), two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms. The Ba(1)-O(7) bond length is 2.87 Å. Both Ba(1)-O(1) bond lengths are 3.05 Å. Both Ba(1)-O(2) bond lengths are 3.02 Å. There are two shorter (3.09 Å) and two longer (3.10 Å) Ba(1)-O(3) bond lengths. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to one O(5), one O(6), two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms. The Ba(2)-O(5) bond length is 2.98 Å. The Ba(2)-O(6) bond length is 3.08 Å. Both Ba(2)-O(1) bond lengths are 3.22 Å. Both Ba(2)-O(2) bond lengths are 3.09 Å. There are two shorter (3.06 Å) and two longer (3.09 Å) Ba(2)-O(4) bond lengths. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to one O(5), one O(7), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. The Ba(3)-O(5) bond length is 2.68 Å. The Ba(3)-O(7) bond length is 2.76 Å. Both Ba(3)-O(2) bond lengths are 2.68 Å. Both Ba(3)-O(3) bond lengths are 3.03 Å. Both Ba(3)-O(4) bond lengths are 2.97 Å. In the fourth Ba site, Ba(4) is bonded to one O(6), two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form distorted BaO7 pentagonal bipyramids that share  a cornercorner with one Ba(4)O7 pentagonal bipyramid, corners with two equivalent V(1)O4 tetrahedra, edges with two equivalent Ba(6)O7 pentagonal bipyramids, and edges with two equivalent V(1)O4 tetrahedra. The Ba(4)-O(6) bond length is 2.59 Å. Both Ba(4)-O(1) bond lengths are 2.68 Å. Both Ba(4)-O(3) bond lengths are 3.00 Å. Both Ba(4)-O(4) bond lengths are 2.95 Å. In the fifth Ba site, Ba(5) is bonded in a 8-coordinate geometry to one O(5), one O(6), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. The Ba(5)-O(5) bond length is 2.68 Å. The Ba(5)-O(6) bond length is 2.74 Å. Both Ba(5)-O(1) bond lengths are 3.07 Å. Both Ba(5)-O(2) bond lengths are 2.98 Å. Both Ba(5)-O(4) bond lengths are 2.70 Å. In the sixth Ba site, Ba(6) is bonded to one O(7), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted BaO7 pentagonal bipyramids that share  a cornercorner with one Ba(6)O7 pentagonal bipyramid, corners with two equivalent V(1)O4 tetrahedra, edges with two equivalent Ba(4)O7 pentagonal bipyramids, and edges with two equivalent V(1)O4 tetrahedra. The Ba(6)-O(7) bond length is 2.63 Å. Both Ba(6)-O(1) bond lengths are 2.95 Å. Both Ba(6)-O(2) bond lengths are 2.92 Å. Both Ba(6)-O(3) bond lengths are 2.66 Å. V(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form VO4 tetrahedra that share  a cornercorner with one Ba(4)O7 pentagonal bipyramid,  a cornercorner with one Ba(6)O7 pentagonal bipyramid,  an edgeedge with one Ba(4)O7 pentagonal bipyramid, and  an edgeedge with one Ba(6)O7 pentagonal bipyramid. The V(1)-O(1) bond length is 1.85 Å. The V(1)-O(2) bond length is 1.85 Å. The V(1)-O(3) bond length is 1.85 Å. The V(1)-O(4) bond length is 1.86 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(4), one Ba(5), one Ba(6), and one V(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Ba(1), one Ba(2), one Ba(3), one Ba(5), one Ba(6), and one V(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Ba(3), one Ba(4), one Ba(6), two equivalent Ba(1), and one V(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Ba(3), one Ba(4), one Ba(5), two equivalent Ba(2), and one V(1) atom. In the fifth O site, O(5) is bonded to two equivalent Ba(2), two equivalent Ba(3), and two equivalent Ba(5) atoms to form corner-sharing OBa6 octahedra. The corner-sharing octahedral tilt angles range from 0-33°. In the sixth O site, O(6) is bonded to two equivalent Ba(2), two equivalent Ba(4), and two equivalent Ba(5) atoms to form corner-sharing OBa6 octahedra. The corner-sharing octahedral tilt angles range from 0-33°. In the seventh O site, O(7) is bonded to two equivalent Ba(1), two equivalent Ba(3), and two equivalent Ba(6) atoms to form corner-sharing OBa6 octahedra. The corner-sharing octahedral tilt angles are 33°.