EuDy2Se4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded to one Se(1), two equivalent Se(2), and three equivalent Se(3) atoms to form a mixture of edge and corner-sharing DySe6 octahedra. The corner-sharing octahedral tilt angles range from 48-65°. In the second Dy site, Dy(2) is bonded to one Se(2), two equivalent Se(1), and three equivalent Se(4) atoms to form a mixture of edge and corner-sharing DySe6 octahedra. The corner-sharing octahedral tilt angles range from 48-65°. Eu(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to one Dy(1), two equivalent Dy(2), and two equivalent Eu(1) atoms to form a mixture of distorted edge and corner-sharing SeEu2Dy3 trigonal bipyramids. In the second Se site, Se(2) is bonded to one Dy(2), two equivalent Dy(1), and two equivalent Eu(1) atoms to form a mixture of distorted edge and corner-sharing SeEu2Dy3 trigonal bipyramids. In the third Se site, Se(3) is bonded to three equivalent Dy(1) and two equivalent Eu(1) atoms to form a mixture of edge and corner-sharing SeEu2Dy3 square pyramids. In the fourth Se site, Se(4) is bonded to three equivalent Dy(2) and two equivalent Eu(1) atoms to form a mixture of distorted edge and corner-sharing SeEu2Dy3 trigonal bipyramids.
EuDy2Se4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded to one Se(1), two equivalent Se(2), and three equivalent Se(3) atoms to form a mixture of edge and corner-sharing DySe6 octahedra. The corner-sharing octahedral tilt angles range from 48-65°. The Dy(1)-Se(1) bond length is 2.87 Å. Both Dy(1)-Se(2) bond lengths are 2.79 Å. There is one shorter (2.86 Å) and two longer (2.88 Å) Dy(1)-Se(3) bond lengths. In the second Dy site, Dy(2) is bonded to one Se(2), two equivalent Se(1), and three equivalent Se(4) atoms to form a mixture of edge and corner-sharing DySe6 octahedra. The corner-sharing octahedral tilt angles range from 48-65°. The Dy(2)-Se(2) bond length is 2.81 Å. Both Dy(2)-Se(1) bond lengths are 2.88 Å. There is one shorter (2.83 Å) and two longer (2.87 Å) Dy(2)-Se(4) bond lengths. Eu(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. Both Eu(1)-Se(1) bond lengths are 3.17 Å. There is one shorter (3.41 Å) and one longer (3.42 Å) Eu(1)-Se(2) bond length. Both Eu(1)-Se(3) bond lengths are 3.18 Å. Both Eu(1)-Se(4) bond lengths are 3.20 Å. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to one Dy(1), two equivalent Dy(2), and two equivalent Eu(1) atoms to form a mixture of distorted edge and corner-sharing SeEu2Dy3 trigonal bipyramids. In the second Se site, Se(2) is bonded to one Dy(2), two equivalent Dy(1), and two equivalent Eu(1) atoms to form a mixture of distorted edge and corner-sharing SeEu2Dy3 trigonal bipyramids. In the third Se site, Se(3) is bonded to three equivalent Dy(1) and two equivalent Eu(1) atoms to form a mixture of edge and corner-sharing SeEu2Dy3 square pyramids. In the fourth Se site, Se(4) is bonded to three equivalent Dy(2) and two equivalent Eu(1) atoms to form a mixture of distorted edge and corner-sharing SeEu2Dy3 trigonal bipyramids.