Y2Se3 crystallizes in the orthorhombic Fddd space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of corner and edge-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles are 5°. In the second Y site, Y(2) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of corner and edge-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles range from 3-5°. 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 Y(1) and two equivalent Y(2) atoms. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to two equivalent Y(1) and two equivalent Y(2) atoms.
Y2Se3 crystallizes in the orthorhombic Fddd space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of corner and edge-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles are 5°. Both Y(1)-Se(1) bond lengths are 2.86 Å. There are two shorter (2.84 Å) and two longer (2.88 Å) Y(1)-Se(2) bond lengths. In the second Y site, Y(2) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of corner and edge-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles range from 3-5°. Both Y(2)-Se(1) bond lengths are 2.88 Å. All Y(2)-Se(2) bond lengths are 2.86 Å. 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 Y(1) and two equivalent Y(2) atoms. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to two equivalent Y(1) and two equivalent Y(2) atoms.