Eu3Ba2Mn2Cu2O12 crystallizes in the tetragonal I4/mmm space group. Ba(1) is bonded to four equivalent O(1), four equivalent O(3), and four equivalent O(4) atoms to form BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Mn(1)O6 octahedra, and faces with four equivalent Cu(1)O5 square pyramids. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a body-centered cubic geometry to eight equivalent O(3) atoms. In the second Eu site, Eu(2) is bonded in a 9-coordinate geometry to four equivalent O(1) and five equivalent O(2) atoms. Mn(1) is bonded to one O(2), one O(4), and four equivalent O(1) atoms to form MnO6 octahedra that share corners with four equivalent Mn(1)O6 octahedra,  a cornercorner with one Cu(1)O5 square pyramid, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 10°. Cu(1) is bonded to one O(4) and four equivalent O(3) atoms to form CuO5 square pyramids that share  a cornercorner with one Mn(1)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. 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), two equivalent Eu(2), and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded to five equivalent Eu(2) and one Mn(1) atom to form distorted OEu5Mn octahedra that share  a cornercorner with one O(4)Ba4MnCu octahedra, corners with four equivalent O(2)Eu5Mn octahedra, and edges with eight equivalent O(2)Eu5Mn octahedra. The corner-sharing octahedral tilt angles range from 0-15°. In the third O site, O(3) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Eu(1), and two equivalent Cu(1) atoms. In the fourth O site, O(4) is bonded to four equivalent Ba(1), one Mn(1), and one Cu(1) atom to form distorted OBa4MnCu octahedra that share  a cornercorner with one O(2)Eu5Mn octahedra, corners with four equivalent O(4)Ba4MnCu octahedra, and edges with four equivalent O(4)Ba4MnCu octahedra. The corner-sharing octahedral tilt angles range from 0-13°.
Eu3Ba2Mn2Cu2O12 crystallizes in the tetragonal I4/mmm space group. Ba(1) is bonded to four equivalent O(1), four equivalent O(3), and four equivalent O(4) atoms to form BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Mn(1)O6 octahedra, and faces with four equivalent Cu(1)O5 square pyramids. All Ba(1)-O(1) bond lengths are 3.07 Å. All Ba(1)-O(3) bond lengths are 2.99 Å. All Ba(1)-O(4) bond lengths are 2.78 Å. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a body-centered cubic geometry to eight equivalent O(3) atoms. All Eu(1)-O(3) bond lengths are 2.48 Å. In the second Eu site, Eu(2) is bonded in a 9-coordinate geometry to four equivalent O(1) and five equivalent O(2) atoms. All Eu(2)-O(1) bond lengths are 2.49 Å. There is one shorter (2.31 Å) and four longer (2.78 Å) Eu(2)-O(2) bond lengths. Mn(1) is bonded to one O(2), one O(4), and four equivalent O(1) atoms to form MnO6 octahedra that share corners with four equivalent Mn(1)O6 octahedra,  a cornercorner with one Cu(1)O5 square pyramid, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 10°. The Mn(1)-O(2) bond length is 2.08 Å. The Mn(1)-O(4) bond length is 1.87 Å. All Mn(1)-O(1) bond lengths are 1.96 Å. Cu(1) is bonded to one O(4) and four equivalent O(3) atoms to form CuO5 square pyramids that share  a cornercorner with one Mn(1)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(4) bond length is 2.36 Å. All Cu(1)-O(3) bond lengths are 1.97 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), two equivalent Eu(2), and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded to five equivalent Eu(2) and one Mn(1) atom to form distorted OEu5Mn octahedra that share  a cornercorner with one O(4)Ba4MnCu octahedra, corners with four equivalent O(2)Eu5Mn octahedra, and edges with eight equivalent O(2)Eu5Mn octahedra. The corner-sharing octahedral tilt angles range from 0-15°. In the third O site, O(3) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Eu(1), and two equivalent Cu(1) atoms. In the fourth O site, O(4) is bonded to four equivalent Ba(1), one Mn(1), and one Cu(1) atom to form distorted OBa4MnCu octahedra that share  a cornercorner with one O(2)Eu5Mn octahedra, corners with four equivalent O(4)Ba4MnCu octahedra, and edges with four equivalent O(4)Ba4MnCu octahedra. The corner-sharing octahedral tilt angles range from 0-13°.