DOE OSTI2020
(SbSeI)2Sb2SeSI2 crystallizes in the monoclinic Pm space group. The structure is one-dimensional and consists of one Sb2SeSI2 ribbon oriented in the (0, 1, 0) direction and one SbSeI ribbon oriented in the (0, 1, 0) direction. In the Sb2SeSI2 ribbon, there are two inequivalent Sb3+ sites. In the first Sb3+ site, Sb3+ is bonded to two equivalent Se2-, one S2-, and two equivalent I1- atoms to form edge-sharing SbSe2SI2 square pyramids. Both Sb–Se bond lengths are 2.83 Å. The Sb–S bond length is 2.50 Å. Both Sb–I bond lengths are 3.16 Å. In the second Sb3+ site, Sb3+ is bonded to one Se2-, two equivalent S2-, and two equivalent I1- atoms to form edge-sharing SbSeS2I2 square pyramids. The Sb–Se bond length is 2.63 Å. Both Sb–S bond lengths are 2.73 Å. Both Sb–I bond lengths are 3.13 Å. Se2- is bonded in a 3-coordinate geometry to three Sb3+ atoms. S2- is bonded in a 3-coordinate geometry to three Sb3+ atoms. There are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a distorted L-shaped geometry to two equivalent Sb3+ atoms. In the second I1- site, I1- is bonded in a distorted L-shaped geometry to two equivalent Sb3+ atoms. In the SbSeI ribbon, there are two inequivalent Sb3+ sites. In the first Sb3+ site, Sb3+ is bonded to three Se2- and two equivalent I1- atoms to form edge-sharing SbSe3I2 square pyramids. There are one shorter (2.64 Å) and two longer (2.84 Å) Sb–Se bond lengths. Both Sb–I bond lengths are 3.15 Å. In the second Sb3+ site, Sb3+ is bonded to three Se2- and two equivalent I1- atoms to form edge-sharing SbSe3I2 square pyramids. There are one shorter (2.63 Å) and two longer (2.83 Å) Sb–Se bond lengths. Both Sb–I bond lengths are 3.16 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to three Sb3+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three Sb3+ atoms. There are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a distorted L-shaped geometry to two equivalent Sb3+ atoms. In the second I1- site, I1- is bonded in a distorted L-shaped geometry to two equivalent Sb3+ atoms.