Cs3SbSe3 crystallizes in the cubic P2_13 space group. There are three inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 6-coordinate geometry to six equivalent Se(1) atoms. In the second Cs site, Cs(2) is bonded to six equivalent Se(1) atoms to form distorted corner-sharing CsSe6 octahedra. The corner-sharing octahedral tilt angles are 64°. In the third Cs site, Cs(3) is bonded in a 6-coordinate geometry to six equivalent Se(1) atoms. Sb(1) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Se(1) atoms. Se(1) is bonded to two equivalent Cs(1), two equivalent Cs(2), two equivalent Cs(3), and one Sb(1) atom to form a mixture of distorted corner, face, and edge-sharing SeCs6Sb pentagonal bipyramids.
Cs3SbSe3 crystallizes in the cubic P2_13 space group. There are three inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 6-coordinate geometry to six equivalent Se(1) atoms. There are three shorter (3.59 Å) and three longer (3.77 Å) Cs(1)-Se(1) bond lengths. In the second Cs site, Cs(2) is bonded to six equivalent Se(1) atoms to form distorted corner-sharing CsSe6 octahedra. The corner-sharing octahedral tilt angles are 64°. There are three shorter (3.87 Å) and three longer (4.09 Å) Cs(2)-Se(1) bond lengths. In the third Cs site, Cs(3) is bonded in a 6-coordinate geometry to six equivalent Se(1) atoms. There are three shorter (3.61 Å) and three longer (3.71 Å) Cs(3)-Se(1) bond lengths. Sb(1) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Se(1) atoms. All Sb(1)-Se(1) bond lengths are 2.58 Å. Se(1) is bonded to two equivalent Cs(1), two equivalent Cs(2), two equivalent Cs(3), and one Sb(1) atom to form a mixture of distorted corner, face, and edge-sharing SeCs6Sb pentagonal bipyramids.