Eu2Se3 crystallizes in the orthorhombic Fddd space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of edge and corner-sharing EuSe6 octahedra. The corner-sharing octahedral tilt angles are 7°. In the second Eu site, Eu(2) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of edge and corner-sharing EuSe6 octahedra. The corner-sharing octahedral tilt angles range from 6-7°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to two equivalent Eu(1) and two equivalent Eu(2) atoms. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to two equivalent Eu(1) and two equivalent Eu(2) atoms.
Eu2Se3 crystallizes in the orthorhombic Fddd space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of edge and corner-sharing EuSe6 octahedra. The corner-sharing octahedral tilt angles are 7°. Both Eu(1)-Se(1) bond lengths are 2.95 Å. There are two shorter (2.92 Å) and two longer (2.97 Å) Eu(1)-Se(2) bond lengths. In the second Eu site, Eu(2) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of edge and corner-sharing EuSe6 octahedra. The corner-sharing octahedral tilt angles range from 6-7°. Both Eu(2)-Se(1) bond lengths are 3.02 Å. There are two shorter (2.95 Å) and two longer (2.99 Å) Eu(2)-Se(2) bond lengths. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to two equivalent Eu(1) and two equivalent Eu(2) atoms. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to two equivalent Eu(1) and two equivalent Eu(2) atoms.