EuSm(CoO3)4 crystallizes in the tetragonal P4/mmm space group. Eu(1) is bonded to four equivalent O(3) and eight equivalent O(1) atoms to form EuO12 cuboctahedra that share corners with four equivalent Eu(1)O12 cuboctahedra, corners with eight equivalent Sm(1)O12 cuboctahedra, and faces with eight equivalent Co(1)O6 octahedra. Sm(1) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form SmO12 cuboctahedra that share corners with four equivalent Sm(1)O12 cuboctahedra, corners with eight equivalent Eu(1)O12 cuboctahedra, and faces with eight equivalent Co(1)O6 octahedra. Co(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form CoO6 octahedra that share corners with six equivalent Co(1)O6 octahedra, faces with two equivalent Eu(1)O12 cuboctahedra, and faces with two equivalent Sm(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-2°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Eu(1), one Sm(1), and two equivalent Co(1) atoms. In the second O site, O(2) is bonded in a distorted square co-planar geometry to two equivalent Sm(1) and two equivalent Co(1) atoms. In the third O site, O(3) is bonded in a distorted square co-planar geometry to two equivalent Eu(1) and two equivalent Co(1) atoms.
EuSm(CoO3)4 crystallizes in the tetragonal P4/mmm space group. Eu(1) is bonded to four equivalent O(3) and eight equivalent O(1) atoms to form EuO12 cuboctahedra that share corners with four equivalent Eu(1)O12 cuboctahedra, corners with eight equivalent Sm(1)O12 cuboctahedra, and faces with eight equivalent Co(1)O6 octahedra. All Eu(1)-O(3) bond lengths are 2.63 Å. All Eu(1)-O(1) bond lengths are 2.66 Å. Sm(1) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form SmO12 cuboctahedra that share corners with four equivalent Sm(1)O12 cuboctahedra, corners with eight equivalent Eu(1)O12 cuboctahedra, and faces with eight equivalent Co(1)O6 octahedra. All Sm(1)-O(2) bond lengths are 2.63 Å. All Sm(1)-O(1) bond lengths are 2.62 Å. Co(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form CoO6 octahedra that share corners with six equivalent Co(1)O6 octahedra, faces with two equivalent Eu(1)O12 cuboctahedra, and faces with two equivalent Sm(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-2°. The Co(1)-O(2) bond length is 1.89 Å. The Co(1)-O(3) bond length is 1.86 Å. All Co(1)-O(1) bond lengths are 1.86 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Eu(1), one Sm(1), and two equivalent Co(1) atoms. In the second O site, O(2) is bonded in a distorted square co-planar geometry to two equivalent Sm(1) and two equivalent Co(1) atoms. In the third O site, O(3) is bonded in a distorted square co-planar geometry to two equivalent Eu(1) and two equivalent Co(1) atoms.