Ba4Pr2(Cu2O5)3 crystallizes in the orthorhombic Fmmm space group. Ba(1) is bonded in a 11-coordinate geometry to one O(2), one O(3), one O(5), two equivalent O(4), two equivalent O(6), and four equivalent O(1) atoms. Pr(1) is bonded in a body-centered cubic geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(5), two equivalent O(1), and two equivalent O(6) atoms to form corner-sharing CuO5 square pyramids. In the second Cu site, Cu(2) is bonded to one O(1), one O(2), one O(3), and two equivalent O(4) atoms to form corner-sharing CuO5 square pyramids. There are six inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1), one Cu(1), and one Cu(2) atom to form distorted OBa4Cu2 octahedra that share corners with two equivalent O(3)Ba2Pr2Cu2 octahedra, corners with four equivalent O(6)Ba4Cu2 octahedra, corners with five equivalent O(1)Ba4Cu2 octahedra, edges with four equivalent O(1)Ba4Cu2 octahedra,  a faceface with one O(3)Ba2Pr2Cu2 octahedra, and faces with two equivalent O(6)Ba4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 8-66°. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Pr(1), and two equivalent Cu(2) atoms. In the third O site, O(3) is bonded to two equivalent Ba(1), two equivalent Pr(1), and two equivalent Cu(2) atoms to form distorted OBa2Pr2Cu2 octahedra that share corners with two equivalent O(3)Ba2Pr2Cu2 octahedra, corners with four equivalent O(1)Ba4Cu2 octahedra, corners with four equivalent O(6)Ba4Cu2 octahedra, and faces with two equivalent O(1)Ba4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-58°. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Pr(1), and two equivalent Cu(2) atoms. In the fifth O site, O(5) is bonded in a distorted linear geometry to four equivalent Ba(1) and two equivalent Cu(1) atoms. In the sixth O site, O(6) is bonded to four equivalent Ba(1) and two equivalent Cu(1) atoms to form distorted OBa4Cu2 octahedra that share corners with two equivalent O(6)Ba4Cu2 octahedra, corners with four equivalent O(3)Ba2Pr2Cu2 octahedra, corners with eight equivalent O(1)Ba4Cu2 octahedra, edges with two equivalent O(6)Ba4Cu2 octahedra, and faces with four equivalent O(1)Ba4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 5-66°.
Ba4Pr2(Cu2O5)3 crystallizes in the orthorhombic Fmmm space group. Ba(1) is bonded in a 11-coordinate geometry to one O(2), one O(3), one O(5), two equivalent O(4), two equivalent O(6), and four equivalent O(1) atoms. The Ba(1)-O(2) bond length is 3.06 Å. The Ba(1)-O(3) bond length is 2.94 Å. The Ba(1)-O(5) bond length is 2.81 Å. Both Ba(1)-O(4) bond lengths are 3.03 Å. Both Ba(1)-O(6) bond lengths are 2.86 Å. There are two shorter (2.77 Å) and two longer (2.87 Å) Ba(1)-O(1) bond lengths. Pr(1) is bonded in a body-centered cubic geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. Both Pr(1)-O(2) bond lengths are 2.49 Å. Both Pr(1)-O(3) bond lengths are 2.52 Å. All Pr(1)-O(4) bond lengths are 2.51 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(5), two equivalent O(1), and two equivalent O(6) atoms to form corner-sharing CuO5 square pyramids. The Cu(1)-O(5) bond length is 1.91 Å. Both Cu(1)-O(1) bond lengths are 1.91 Å. Both Cu(1)-O(6) bond lengths are 1.98 Å. In the second Cu site, Cu(2) is bonded to one O(1), one O(2), one O(3), and two equivalent O(4) atoms to form corner-sharing CuO5 square pyramids. The Cu(2)-O(1) bond length is 2.14 Å. The Cu(2)-O(2) bond length is 2.00 Å. The Cu(2)-O(3) bond length is 2.03 Å. Both Cu(2)-O(4) bond lengths are 2.00 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1), one Cu(1), and one Cu(2) atom to form distorted OBa4Cu2 octahedra that share corners with two equivalent O(3)Ba2Pr2Cu2 octahedra, corners with four equivalent O(6)Ba4Cu2 octahedra, corners with five equivalent O(1)Ba4Cu2 octahedra, edges with four equivalent O(1)Ba4Cu2 octahedra,  a faceface with one O(3)Ba2Pr2Cu2 octahedra, and faces with two equivalent O(6)Ba4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 8-66°. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Pr(1), and two equivalent Cu(2) atoms. In the third O site, O(3) is bonded to two equivalent Ba(1), two equivalent Pr(1), and two equivalent Cu(2) atoms to form distorted OBa2Pr2Cu2 octahedra that share corners with two equivalent O(3)Ba2Pr2Cu2 octahedra, corners with four equivalent O(1)Ba4Cu2 octahedra, corners with four equivalent O(6)Ba4Cu2 octahedra, and faces with two equivalent O(1)Ba4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-58°. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Pr(1), and two equivalent Cu(2) atoms. In the fifth O site, O(5) is bonded in a distorted linear geometry to four equivalent Ba(1) and two equivalent Cu(1) atoms. In the sixth O site, O(6) is bonded to four equivalent Ba(1) and two equivalent Cu(1) atoms to form distorted OBa4Cu2 octahedra that share corners with two equivalent O(6)Ba4Cu2 octahedra, corners with four equivalent O(3)Ba2Pr2Cu2 octahedra, corners with eight equivalent O(1)Ba4Cu2 octahedra, edges with two equivalent O(6)Ba4Cu2 octahedra, and faces with four equivalent O(1)Ba4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 5-66°.