Ba5Dy8Zn4O21 crystallizes in the tetragonal I4/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(2), four equivalent O(1), and four equivalent O(3) atoms. In the second Ba site, Ba(2) is bonded in a distorted q6 geometry to two equivalent O(4) and eight equivalent O(2) atoms. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded to one O(4), two equivalent O(1), and four equivalent O(2) atoms to form distorted DyO7 pentagonal bipyramids that share  a cornercorner with one Dy(1)O7 pentagonal bipyramid, corners with two equivalent Zn(1)O5 trigonal bipyramids, edges with two equivalent Zn(1)O5 trigonal bipyramids, and faces with two equivalent Dy(1)O7 pentagonal bipyramids. In the second Dy site, Dy(2) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(2), and four equivalent O(1) atoms. Zn(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form distorted ZnO5 trigonal bipyramids that share corners with two equivalent Dy(1)O7 pentagonal bipyramids and edges with two equivalent Dy(1)O7 pentagonal bipyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Dy(1), two equivalent Dy(2), and one Zn(1) atom. In the second O site, O(2) is bonded to one Ba(1), one Ba(2), one Dy(2), two equivalent Dy(1), and one Zn(1) atom to form distorted OBa2Dy3Zn octahedra that share  a cornercorner with one O(4)Ba2Dy4 octahedra, corners with three equivalent O(3)Ba4DyZn octahedra, corners with six equivalent O(2)Ba2Dy3Zn octahedra, edges with two equivalent O(2)Ba2Dy3Zn octahedra,  a faceface with one O(4)Ba2Dy4 octahedra,  a faceface with one O(3)Ba4DyZn octahedra, and faces with two equivalent O(2)Ba2Dy3Zn octahedra. The corner-sharing octahedral tilt angles range from 0-76°. In the third O site, O(3) is bonded to four equivalent Ba(1), one Dy(2), and one Zn(1) atom to form distorted OBa4DyZn octahedra that share corners with two equivalent O(3)Ba4DyZn octahedra, corners with six equivalent O(2)Ba2Dy3Zn octahedra, edges with five equivalent O(3)Ba4DyZn octahedra, and faces with two equivalent O(2)Ba2Dy3Zn octahedra. The corner-sharing octahedral tilt angles range from 6-59°. In the fourth O site, O(4) is bonded to two equivalent Ba(2) and four equivalent Dy(1) atoms to form OBa2Dy4 octahedra that share corners with two equivalent O(4)Ba2Dy4 octahedra, corners with eight equivalent O(2)Ba2Dy3Zn octahedra, and faces with eight equivalent O(2)Ba2Dy3Zn octahedra. The corner-sharing octahedral tilt angles range from 0-61°.
Ba5Dy8Zn4O21 crystallizes in the tetragonal I4/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(2), four equivalent O(1), and four equivalent O(3) atoms. Both Ba(1)-O(2) bond lengths are 2.93 Å. There are two shorter (3.22 Å) and two longer (3.26 Å) Ba(1)-O(1) bond lengths. There are a spread of Ba(1)-O(3) bond distances ranging from 2.67-2.88 Å. In the second Ba site, Ba(2) is bonded in a distorted q6 geometry to two equivalent O(4) and eight equivalent O(2) atoms. Both Ba(2)-O(4) bond lengths are 2.88 Å. All Ba(2)-O(2) bond lengths are 2.94 Å. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded to one O(4), two equivalent O(1), and four equivalent O(2) atoms to form distorted DyO7 pentagonal bipyramids that share  a cornercorner with one Dy(1)O7 pentagonal bipyramid, corners with two equivalent Zn(1)O5 trigonal bipyramids, edges with two equivalent Zn(1)O5 trigonal bipyramids, and faces with two equivalent Dy(1)O7 pentagonal bipyramids. The Dy(1)-O(4) bond length is 2.33 Å. Both Dy(1)-O(1) bond lengths are 2.32 Å. There are two shorter (2.31 Å) and two longer (2.43 Å) Dy(1)-O(2) bond lengths. In the second Dy site, Dy(2) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(2), and four equivalent O(1) atoms. The Dy(2)-O(3) bond length is 2.51 Å. Both Dy(2)-O(2) bond lengths are 2.41 Å. There are two shorter (2.30 Å) and two longer (2.34 Å) Dy(2)-O(1) bond lengths. Zn(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(2) atoms to form distorted ZnO5 trigonal bipyramids that share corners with two equivalent Dy(1)O7 pentagonal bipyramids and edges with two equivalent Dy(1)O7 pentagonal bipyramids. The Zn(1)-O(3) bond length is 2.00 Å. Both Zn(1)-O(1) bond lengths are 2.07 Å. Both Zn(1)-O(2) bond lengths are 2.15 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Dy(1), two equivalent Dy(2), and one Zn(1) atom. In the second O site, O(2) is bonded to one Ba(1), one Ba(2), one Dy(2), two equivalent Dy(1), and one Zn(1) atom to form distorted OBa2Dy3Zn octahedra that share  a cornercorner with one O(4)Ba2Dy4 octahedra, corners with three equivalent O(3)Ba4DyZn octahedra, corners with six equivalent O(2)Ba2Dy3Zn octahedra, edges with two equivalent O(2)Ba2Dy3Zn octahedra,  a faceface with one O(4)Ba2Dy4 octahedra,  a faceface with one O(3)Ba4DyZn octahedra, and faces with two equivalent O(2)Ba2Dy3Zn octahedra. The corner-sharing octahedral tilt angles range from 0-76°. In the third O site, O(3) is bonded to four equivalent Ba(1), one Dy(2), and one Zn(1) atom to form distorted OBa4DyZn octahedra that share corners with two equivalent O(3)Ba4DyZn octahedra, corners with six equivalent O(2)Ba2Dy3Zn octahedra, edges with five equivalent O(3)Ba4DyZn octahedra, and faces with two equivalent O(2)Ba2Dy3Zn octahedra. The corner-sharing octahedral tilt angles range from 6-59°. In the fourth O site, O(4) is bonded to two equivalent Ba(2) and four equivalent Dy(1) atoms to form OBa2Dy4 octahedra that share corners with two equivalent O(4)Ba2Dy4 octahedra, corners with eight equivalent O(2)Ba2Dy3Zn octahedra, and faces with eight equivalent O(2)Ba2Dy3Zn octahedra. The corner-sharing octahedral tilt angles range from 0-61°.