Sb2Te3 crystallizes in the monoclinic C2/m space group. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 4-coordinate geometry to one Sb(2), one Te(3), two equivalent Te(1), and two equivalent Te(2) atoms. In the second Sb site, Sb(2) is bonded in a 6-coordinate geometry to one Sb(1), two equivalent Sb(2), one Te(1), and two equivalent Te(3) atoms. There are three inequivalent Te sites. In the first Te site, Te(1) is bonded in a 6-coordinate geometry to one Sb(2), two equivalent Sb(1), one Te(2), and two equivalent Te(3) atoms. In the second Te site, Te(2) is bonded to two equivalent Sb(1), one Te(1), and two equivalent Te(3) atoms to form distorted corner-sharing TeSb2Te3 trigonal bipyramids. In the third Te site, Te(3) is bonded in a 7-coordinate geometry to one Sb(1), two equivalent Sb(2), two equivalent Te(1), and two equivalent Te(2) atoms.
Sb2Te3 crystallizes in the monoclinic C2/m space group. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 4-coordinate geometry to one Sb(2), one Te(3), two equivalent Te(1), and two equivalent Te(2) atoms. The Sb(1)-Sb(2) bond length is 3.24 Å. The Sb(1)-Te(3) bond length is 3.53 Å. There is one shorter (2.85 Å) and one longer (2.90 Å) Sb(1)-Te(1) bond length. Both Sb(1)-Te(2) bond lengths are 3.02 Å. In the second Sb site, Sb(2) is bonded in a 6-coordinate geometry to one Sb(1), two equivalent Sb(2), one Te(1), and two equivalent Te(3) atoms. There is one shorter (2.84 Å) and one longer (2.93 Å) Sb(2)-Sb(2) bond length. The Sb(2)-Te(1) bond length is 3.14 Å. Both Sb(2)-Te(3) bond lengths are 3.48 Å. There are three inequivalent Te sites. In the first Te site, Te(1) is bonded in a 6-coordinate geometry to one Sb(2), two equivalent Sb(1), one Te(2), and two equivalent Te(3) atoms. The Te(1)-Te(2) bond length is 3.21 Å. Both Te(1)-Te(3) bond lengths are 3.13 Å. In the second Te site, Te(2) is bonded to two equivalent Sb(1), one Te(1), and two equivalent Te(3) atoms to form distorted corner-sharing TeSb2Te3 trigonal bipyramids. There is one shorter (2.83 Å) and one longer (2.91 Å) Te(2)-Te(3) bond length. In the third Te site, Te(3) is bonded in a 7-coordinate geometry to one Sb(1), two equivalent Sb(2), two equivalent Te(1), and two equivalent Te(2) atoms.