DOE OSTI2020
Sb4(TeSe)3 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are four inequivalent Sb3+ sites. In the first Sb3+ site, Sb3+ is bonded to one Te2- and five Se2- atoms to form SbTeSe5 octahedra that share corners with three equivalent SbTe3Se3 octahedra and edges with nine SbTeSe5 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. The Sb–Te bond length is 3.05 Å. There are a spread of Sb–Se bond distances ranging from 2.86–3.02 Å. In the second Sb3+ site, Sb3+ is bonded to two equivalent Te2- and four Se2- atoms to form SbTe2Se4 octahedra that share corners with three equivalent SbTe3Se3 octahedra and edges with nine SbTeSe5 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. Both Sb–Te bond lengths are 3.00 Å. There are a spread of Sb–Se bond distances ranging from 2.79–3.05 Å. In the third Sb3+ site, Sb3+ is bonded to three Te2- and three Se2- atoms to form SbTe3Se3 octahedra that share corners with three equivalent SbTe2Se4 octahedra and edges with nine SbTeSe5 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. There are one shorter (2.99 Å) and two longer (3.01 Å) Sb–Te bond lengths. There are two shorter (3.03 Å) and one longer (3.04 Å) Sb–Se bond lengths. In the fourth Sb3+ site, Sb3+ is bonded to three Te2- and three Se2- atoms to form a mixture of edge and corner-sharing SbTe3Se3 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are two shorter (3.00 Å) and one longer (3.01 Å) Sb–Te bond lengths. There are one shorter (3.03 Å) and two longer (3.07 Å) Sb–Se bond lengths. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three Sb3+ and one Te2- atom. The Te–Te bond length is 3.78 Å. In the second Te2- site, Te2- is bonded in a 4-coordinate geometry to three Sb3+ and one Se2- atom. The Te–Se bond length is 4.00 Å. In the third Te2- site, Te2- is bonded in a 5-coordinate geometry to three Sb3+, one Te2-, and two equivalent Se2- atoms. Both Te–Se bond lengths are 4.00 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to six Sb3+ atoms to form edge-sharing SeSb6 octahedra. In the second Se2- site, Se2- is bonded to six Sb3+ atoms to form edge-sharing SeSb6 octahedra. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to three Sb3+ and three Te2- atoms.