CsSiBiS4 crystallizes in the monoclinic P2_1/c space group. Cs(1) is bonded in a 8-coordinate geometry to one S(2), two equivalent S(1), two equivalent S(3), and three equivalent S(4) atoms. Si(1) is bonded to one S(1), one S(2), one S(3), and one S(4) atom to form SiS4 tetrahedra that share  a cornercorner with one Bi(1)S5 square pyramid and edges with two equivalent Bi(1)S5 square pyramids. Bi(1) is bonded to one S(1), one S(3), one S(4), and two equivalent S(2) atoms to form distorted BiS5 square pyramids that share  a cornercorner with one Si(1)S4 tetrahedra,  an edgeedge with one Bi(1)S5 square pyramid, and edges with two equivalent Si(1)S4 tetrahedra. There are four inequivalent S sites. In the first S site, S(1) is bonded in a 4-coordinate geometry to two equivalent Cs(1), one Si(1), and one Bi(1) atom. In the second S site, S(2) is bonded in a distorted rectangular see-saw-like geometry to one Cs(1), one Si(1), and two equivalent Bi(1) atoms. In the third S site, S(3) is bonded in a 1-coordinate geometry to two equivalent Cs(1), one Si(1), and one Bi(1) atom. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to three equivalent Cs(1), one Si(1), and one Bi(1) atom.
CsSiBiS4 crystallizes in the monoclinic P2_1/c space group. Cs(1) is bonded in a 8-coordinate geometry to one S(2), two equivalent S(1), two equivalent S(3), and three equivalent S(4) atoms. The Cs(1)-S(2) bond length is 3.52 Å. There is one shorter (3.60 Å) and one longer (3.86 Å) Cs(1)-S(1) bond length. There is one shorter (3.69 Å) and one longer (3.85 Å) Cs(1)-S(3) bond length. There are two shorter (3.69 Å) and one longer (3.80 Å) Cs(1)-S(4) bond length. Si(1) is bonded to one S(1), one S(2), one S(3), and one S(4) atom to form SiS4 tetrahedra that share  a cornercorner with one Bi(1)S5 square pyramid and edges with two equivalent Bi(1)S5 square pyramids. The Si(1)-S(1) bond length is 2.14 Å. The Si(1)-S(2) bond length is 2.18 Å. The Si(1)-S(3) bond length is 2.12 Å. The Si(1)-S(4) bond length is 2.12 Å. Bi(1) is bonded to one S(1), one S(3), one S(4), and two equivalent S(2) atoms to form distorted BiS5 square pyramids that share  a cornercorner with one Si(1)S4 tetrahedra,  an edgeedge with one Bi(1)S5 square pyramid, and edges with two equivalent Si(1)S4 tetrahedra. The Bi(1)-S(1) bond length is 2.75 Å. The Bi(1)-S(3) bond length is 2.86 Å. The Bi(1)-S(4) bond length is 2.82 Å. There is one shorter (2.72 Å) and one longer (2.98 Å) Bi(1)-S(2) bond length. There are four inequivalent S sites. In the first S site, S(1) is bonded in a 4-coordinate geometry to two equivalent Cs(1), one Si(1), and one Bi(1) atom. In the second S site, S(2) is bonded in a distorted rectangular see-saw-like geometry to one Cs(1), one Si(1), and two equivalent Bi(1) atoms. In the third S site, S(3) is bonded in a 1-coordinate geometry to two equivalent Cs(1), one Si(1), and one Bi(1) atom. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to three equivalent Cs(1), one Si(1), and one Bi(1) atom.