EuNd(FeO3)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 Nd(1)O12 cuboctahedra, and faces with eight equivalent Fe(1)O6 octahedra. Nd(1) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form NdO12 cuboctahedra that share corners with four equivalent Nd(1)O12 cuboctahedra, corners with eight equivalent Eu(1)O12 cuboctahedra, and faces with eight equivalent Fe(1)O6 octahedra. Fe(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form FeO6 octahedra that share corners with six equivalent Fe(1)O6 octahedra, faces with two equivalent Eu(1)O12 cuboctahedra, and faces with two equivalent Nd(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-1°. 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 Nd(1), and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded in a distorted square co-planar geometry to two equivalent Nd(1) and two equivalent Fe(1) atoms. In the third O site, O(3) is bonded in a distorted linear geometry to two equivalent Eu(1) and two equivalent Fe(1) atoms.
EuNd(FeO3)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 Nd(1)O12 cuboctahedra, and faces with eight equivalent Fe(1)O6 octahedra. All Eu(1)-O(3) bond lengths are 2.61 Å. All Eu(1)-O(1) bond lengths are 2.61 Å. Nd(1) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form NdO12 cuboctahedra that share corners with four equivalent Nd(1)O12 cuboctahedra, corners with eight equivalent Eu(1)O12 cuboctahedra, and faces with eight equivalent Fe(1)O6 octahedra. All Nd(1)-O(2) bond lengths are 2.61 Å. All Nd(1)-O(1) bond lengths are 2.60 Å. Fe(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form FeO6 octahedra that share corners with six equivalent Fe(1)O6 octahedra, faces with two equivalent Eu(1)O12 cuboctahedra, and faces with two equivalent Nd(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-1°. The Fe(1)-O(2) bond length is 1.85 Å. The Fe(1)-O(3) bond length is 1.83 Å. All Fe(1)-O(1) bond lengths are 1.84 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 Nd(1), and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded in a distorted square co-planar geometry to two equivalent Nd(1) and two equivalent Fe(1) atoms. In the third O site, O(3) is bonded in a distorted linear geometry to two equivalent Eu(1) and two equivalent Fe(1) atoms.