CsSiTe3 crystallizes in the monoclinic Cc space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 7-coordinate geometry to one Te(2), one Te(5), one Te(6), two equivalent Te(1), and two equivalent Te(3) atoms. In the second Cs site, Cs(2) is bonded in a 7-coordinate geometry to one Te(2), one Te(4), one Te(6), two equivalent Te(3), and two equivalent Te(5) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one Te(1), one Te(3), one Te(4), and one Te(6) atom to form corner-sharing SiTe4 tetrahedra. In the second Si site, Si(2) is bonded to one Te(1), one Te(2), one Te(5), and one Te(6) atom to form corner-sharing SiTe4 tetrahedra. There are six inequivalent Te sites. In the first Te site, Te(1) is bonded in a 4-coordinate geometry to two equivalent Cs(1), one Si(1), and one Si(2) atom. In the second Te site, Te(2) is bonded in a distorted rectangular see-saw-like geometry to one Cs(1), one Cs(2), one Si(2), and one Te(4) atom. In the third Te site, Te(3) is bonded in a 5-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), and one Si(1) atom. In the fourth Te site, Te(4) is bonded in a 1-coordinate geometry to one Cs(2), one Si(1), and one Te(2) atom. In the fifth Te site, Te(5) is bonded in a 1-coordinate geometry to one Cs(1), two equivalent Cs(2), and one Si(2) atom. In the sixth Te site, Te(6) is bonded in a 2-coordinate geometry to one Cs(1), one Cs(2), one Si(1), and one Si(2) atom.
CsSiTe3 crystallizes in the monoclinic Cc space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 7-coordinate geometry to one Te(2), one Te(5), one Te(6), two equivalent Te(1), and two equivalent Te(3) atoms. The Cs(1)-Te(2) bond length is 3.92 Å. The Cs(1)-Te(5) bond length is 3.90 Å. The Cs(1)-Te(6) bond length is 4.30 Å. Both Cs(1)-Te(1) bond lengths are 4.15 Å. There is one shorter (3.90 Å) and one longer (4.09 Å) Cs(1)-Te(3) bond length. In the second Cs site, Cs(2) is bonded in a 7-coordinate geometry to one Te(2), one Te(4), one Te(6), two equivalent Te(3), and two equivalent Te(5) atoms. The Cs(2)-Te(2) bond length is 3.98 Å. The Cs(2)-Te(4) bond length is 3.91 Å. The Cs(2)-Te(6) bond length is 4.07 Å. There is one shorter (4.09 Å) and one longer (4.27 Å) Cs(2)-Te(3) bond length. There is one shorter (3.91 Å) and one longer (3.93 Å) Cs(2)-Te(5) bond length. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one Te(1), one Te(3), one Te(4), and one Te(6) atom to form corner-sharing SiTe4 tetrahedra. The Si(1)-Te(1) bond length is 2.58 Å. The Si(1)-Te(3) bond length is 2.44 Å. The Si(1)-Te(4) bond length is 2.58 Å. The Si(1)-Te(6) bond length is 2.56 Å. In the second Si site, Si(2) is bonded to one Te(1), one Te(2), one Te(5), and one Te(6) atom to form corner-sharing SiTe4 tetrahedra. The Si(2)-Te(1) bond length is 2.55 Å. The Si(2)-Te(2) bond length is 2.51 Å. The Si(2)-Te(5) bond length is 2.48 Å. The Si(2)-Te(6) bond length is 2.53 Å. There are six inequivalent Te sites. In the first Te site, Te(1) is bonded in a 4-coordinate geometry to two equivalent Cs(1), one Si(1), and one Si(2) atom. In the second Te site, Te(2) is bonded in a distorted rectangular see-saw-like geometry to one Cs(1), one Cs(2), one Si(2), and one Te(4) atom. The Te(2)-Te(4) bond length is 2.90 Å. In the third Te site, Te(3) is bonded in a 5-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), and one Si(1) atom. In the fourth Te site, Te(4) is bonded in a 1-coordinate geometry to one Cs(2), one Si(1), and one Te(2) atom. In the fifth Te site, Te(5) is bonded in a 1-coordinate geometry to one Cs(1), two equivalent Cs(2), and one Si(2) atom. In the sixth Te site, Te(6) is bonded in a 2-coordinate geometry to one Cs(1), one Cs(2), one Si(1), and one Si(2) atom.