SiPb2S4 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a 6-coordinate geometry to one S(1), one S(3), two equivalent S(2), and two equivalent S(4) atoms. In the second Pb site, Pb(2) is bonded in a 3-coordinate geometry to one S(1), one S(3), and one S(4) atom. Si(1) is bonded in a tetrahedral geometry to one S(1), one S(2), one S(3), and one S(4) atom. There are four inequivalent S sites. In the first S site, S(1) is bonded in a distorted single-bond geometry to one Pb(1), one Pb(2), and one Si(1) atom. In the second S site, S(2) is bonded in a distorted single-bond geometry to two equivalent Pb(1) and one Si(1) atom. In the third S site, S(3) is bonded in a distorted single-bond geometry to one Pb(1), one Pb(2), and one Si(1) atom. In the fourth S site, S(4) is bonded in a distorted single-bond geometry to one Pb(2), two equivalent Pb(1), and one Si(1) atom.
SiPb2S4 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a 6-coordinate geometry to one S(1), one S(3), two equivalent S(2), and two equivalent S(4) atoms. The Pb(1)-S(1) bond length is 3.11 Å. The Pb(1)-S(3) bond length is 2.88 Å. There is one shorter (2.87 Å) and one longer (3.06 Å) Pb(1)-S(2) bond length. There is one shorter (3.04 Å) and one longer (3.25 Å) Pb(1)-S(4) bond length. In the second Pb site, Pb(2) is bonded in a 3-coordinate geometry to one S(1), one S(3), and one S(4) atom. The Pb(2)-S(1) bond length is 2.76 Å. The Pb(2)-S(3) bond length is 2.84 Å. The Pb(2)-S(4) bond length is 2.82 Å. Si(1) is bonded in a tetrahedral geometry to one S(1), one S(2), one S(3), and one S(4) atom. The Si(1)-S(1) bond length is 2.11 Å. The Si(1)-S(2) bond length is 2.13 Å. The Si(1)-S(3) bond length is 2.13 Å. The Si(1)-S(4) bond length is 2.13 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded in a distorted single-bond geometry to one Pb(1), one Pb(2), and one Si(1) atom. In the second S site, S(2) is bonded in a distorted single-bond geometry to two equivalent Pb(1) and one Si(1) atom. In the third S site, S(3) is bonded in a distorted single-bond geometry to one Pb(1), one Pb(2), and one Si(1) atom. In the fourth S site, S(4) is bonded in a distorted single-bond geometry to one Pb(2), two equivalent Pb(1), and one Si(1) atom.