Zr2Se3 crystallizes in the monoclinic C2/m space group. There are three inequivalent Zr sites. In the first Zr site, Zr(1) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of corner and edge-sharing ZrSe6 octahedra. The corner-sharing octahedral tilt angles are 5°. In the second Zr site, Zr(2) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of corner and edge-sharing ZrSe6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the third Zr site, Zr(3) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of corner and edge-sharing ZrSe6 octahedra. The corner-sharing octahedral tilt angles range from 1-5°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Zr(2), one Zr(3), and two equivalent Zr(1) atoms. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to one Zr(2), one Zr(3), and two equivalent Zr(1) atoms.
Zr2Se3 crystallizes in the monoclinic C2/m space group. There are three inequivalent Zr sites. In the first Zr site, Zr(1) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of corner and edge-sharing ZrSe6 octahedra. The corner-sharing octahedral tilt angles are 5°. Both Zr(1)-Se(1) bond lengths are 2.76 Å. There are two shorter (2.65 Å) and two longer (2.76 Å) Zr(1)-Se(2) bond lengths. In the second Zr site, Zr(2) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of corner and edge-sharing ZrSe6 octahedra. The corner-sharing octahedral tilt angles are 1°. Both Zr(2)-Se(1) bond lengths are 2.67 Å. All Zr(2)-Se(2) bond lengths are 2.76 Å. In the third Zr site, Zr(3) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form a mixture of corner and edge-sharing ZrSe6 octahedra. The corner-sharing octahedral tilt angles range from 1-5°. Both Zr(3)-Se(1) bond lengths are 2.71 Å. All Zr(3)-Se(2) bond lengths are 2.67 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Zr(2), one Zr(3), and two equivalent Zr(1) atoms. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to one Zr(2), one Zr(3), and two equivalent Zr(1) atoms.