Ba2PrCu3O8 crystallizes in the tetragonal P4/mmm space group. Ba(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with eight equivalent Ba(1)O12 cuboctahedra, faces with five equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Cu(2)O6 octahedra, and faces with four equivalent Cu(1)O5 square pyramids. Pr(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(3) and four equivalent O(1) atoms to form CuO5 square pyramids that share  a cornercorner with one Cu(2)O6 octahedra, corners with four equivalent Cu(1)O5 square pyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. In the second Cu site, Cu(2) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form CuO6 octahedra that share corners with four equivalent Cu(2)O6 octahedra, corners with two equivalent Cu(1)O5 square pyramids, and faces with eight equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Pr(1), and two equivalent Cu(1) atoms. In the second O site, O(2) is bonded to four equivalent Ba(1) and two equivalent Cu(2) atoms to form a mixture of distorted face, corner, and edge-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-59°. In the third O site, O(3) is bonded to four equivalent Ba(1), one Cu(1), and one Cu(2) atom to form a mixture of distorted face, corner, and edge-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-59°.
Ba2PrCu3O8 crystallizes in the tetragonal P4/mmm space group. Ba(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with eight equivalent Ba(1)O12 cuboctahedra, faces with five equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Cu(2)O6 octahedra, and faces with four equivalent Cu(1)O5 square pyramids. All Ba(1)-O(1) bond lengths are 3.10 Å. All Ba(1)-O(2) bond lengths are 2.80 Å. All Ba(1)-O(3) bond lengths are 2.81 Å. Pr(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. All Pr(1)-O(1) bond lengths are 2.50 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(3) and four equivalent O(1) atoms to form CuO5 square pyramids that share  a cornercorner with one Cu(2)O6 octahedra, corners with four equivalent Cu(1)O5 square pyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. The Cu(1)-O(3) bond length is 1.98 Å. All Cu(1)-O(1) bond lengths are 2.02 Å. In the second Cu site, Cu(2) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form CuO6 octahedra that share corners with four equivalent Cu(2)O6 octahedra, corners with two equivalent Cu(1)O5 square pyramids, and faces with eight equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. Both Cu(2)-O(3) bond lengths are 2.00 Å. All Cu(2)-O(2) bond lengths are 1.99 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Pr(1), and two equivalent Cu(1) atoms. In the second O site, O(2) is bonded to four equivalent Ba(1) and two equivalent Cu(2) atoms to form a mixture of distorted face, corner, and edge-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-59°. In the third O site, O(3) is bonded to four equivalent Ba(1), one Cu(1), and one Cu(2) atom to form a mixture of distorted face, corner, and edge-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-59°.