BaTmFeCuO5 crystallizes in the tetragonal P4mm space group. Ba(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(3) atoms. Tm(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. Fe(1) is bonded to one O(3) and four equivalent O(2) atoms to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Cu(1)O5 square pyramid and corners with four equivalent Fe(1)O5 trigonal bipyramids. Cu(1) is bonded to one O(3) and four equivalent O(1) atoms to form distorted CuO5 square pyramids that share corners with four equivalent Cu(1)O5 square pyramids and  a cornercorner with one Fe(1)O5 trigonal bipyramid. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Tm(1), and two equivalent Cu(1) atoms. In the second O site, O(2) is bonded to two equivalent Tm(1) and two equivalent Fe(1) atoms to form distorted OTm2Fe2 tetrahedra that share corners with two equivalent O(3)Ba4FeCu octahedra, corners with four equivalent O(2)Tm2Fe2 tetrahedra, and edges with four equivalent O(2)Tm2Fe2 tetrahedra. The corner-sharing octahedral tilt angles are 73°. In the third O site, O(3) is bonded to four equivalent Ba(1), one Fe(1), and one Cu(1) atom to form distorted OBa4FeCu octahedra that share corners with four equivalent O(3)Ba4FeCu octahedra, corners with four equivalent O(2)Tm2Fe2 tetrahedra, and edges with four equivalent O(3)Ba4FeCu octahedra. The corner-sharing octahedral tilt angles are 21°.
BaTmFeCuO5 crystallizes in the tetragonal P4mm space group. Ba(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(3) atoms. All Ba(1)-O(1) bond lengths are 2.94 Å. All Ba(1)-O(3) bond lengths are 2.79 Å. Tm(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. All Tm(1)-O(1) bond lengths are 2.43 Å. All Tm(1)-O(2) bond lengths are 2.34 Å. Fe(1) is bonded to one O(3) and four equivalent O(2) atoms to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Cu(1)O5 square pyramid and corners with four equivalent Fe(1)O5 trigonal bipyramids. The Fe(1)-O(3) bond length is 1.87 Å. All Fe(1)-O(2) bond lengths are 2.02 Å. Cu(1) is bonded to one O(3) and four equivalent O(1) atoms to form distorted CuO5 square pyramids that share corners with four equivalent Cu(1)O5 square pyramids and  a cornercorner with one Fe(1)O5 trigonal bipyramid. The Cu(1)-O(3) bond length is 2.52 Å. All Cu(1)-O(1) bond lengths are 1.95 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Tm(1), and two equivalent Cu(1) atoms. In the second O site, O(2) is bonded to two equivalent Tm(1) and two equivalent Fe(1) atoms to form distorted OTm2Fe2 tetrahedra that share corners with two equivalent O(3)Ba4FeCu octahedra, corners with four equivalent O(2)Tm2Fe2 tetrahedra, and edges with four equivalent O(2)Tm2Fe2 tetrahedra. The corner-sharing octahedral tilt angles are 73°. In the third O site, O(3) is bonded to four equivalent Ba(1), one Fe(1), and one Cu(1) atom to form distorted OBa4FeCu octahedra that share corners with four equivalent O(3)Ba4FeCu octahedra, corners with four equivalent O(2)Tm2Fe2 tetrahedra, and edges with four equivalent O(3)Ba4FeCu octahedra. The corner-sharing octahedral tilt angles are 21°.