Ti2Se3 crystallizes in the trigonal P-31c space group. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to six equivalent Se(1) atoms to form a mixture of corner, edge, and face-sharing TiSe6 octahedra. The corner-sharing octahedral tilt angles are 48°. In the second Ti site, Ti(2) is bonded to six equivalent Se(1) atoms to form a mixture of corner and edge-sharing TiSe6 octahedra. The corner-sharing octahedral tilt angles are 49°. In the third Ti site, Ti(3) is bonded to six equivalent Se(1) atoms to form a mixture of corner and face-sharing TiSe6 octahedra. The corner-sharing octahedral tilt angles range from 48-49°. Se(1) is bonded in a rectangular see-saw-like geometry to one Ti(2), one Ti(3), and two equivalent Ti(1) atoms.
Ti2Se3 crystallizes in the trigonal P-31c space group. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to six equivalent Se(1) atoms to form a mixture of corner, edge, and face-sharing TiSe6 octahedra. The corner-sharing octahedral tilt angles are 48°. There are three shorter (2.58 Å) and three longer (2.62 Å) Ti(1)-Se(1) bond lengths. In the second Ti site, Ti(2) is bonded to six equivalent Se(1) atoms to form a mixture of corner and edge-sharing TiSe6 octahedra. The corner-sharing octahedral tilt angles are 49°. All Ti(2)-Se(1) bond lengths are 2.58 Å. In the third Ti site, Ti(3) is bonded to six equivalent Se(1) atoms to form a mixture of corner and face-sharing TiSe6 octahedra. The corner-sharing octahedral tilt angles range from 48-49°. All Ti(3)-Se(1) bond lengths are 2.58 Å. Se(1) is bonded in a rectangular see-saw-like geometry to one Ti(2), one Ti(3), and two equivalent Ti(1) atoms.