Pr4(SiS4)3 crystallizes in the trigonal R3c space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 9-coordinate geometry to three equivalent S(3) and six equivalent S(2) atoms. In the second Pr site, Pr(2) is bonded in a 7-coordinate geometry to one S(2), two equivalent S(3), two equivalent S(4), and three equivalent S(1) atoms. 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 4-coordinate geometry to three equivalent Pr(2) and one Si(1) atom. In the second S site, S(2) is bonded to one Pr(2), two equivalent Pr(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing SPr3Si tetrahedra. In the third S site, S(3) is bonded in a 4-coordinate geometry to one Pr(1), two equivalent Pr(2), and one Si(1) atom. In the fourth S site, S(4) is bonded in a 3-coordinate geometry to two equivalent Pr(2) and one Si(1) atom.
Pr4(SiS4)3 crystallizes in the trigonal R3c space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 9-coordinate geometry to three equivalent S(3) and six equivalent S(2) atoms. All Pr(1)-S(3) bond lengths are 3.38 Å. There are three shorter (2.90 Å) and three longer (2.91 Å) Pr(1)-S(2) bond lengths. In the second Pr site, Pr(2) is bonded in a 7-coordinate geometry to one S(2), two equivalent S(3), two equivalent S(4), and three equivalent S(1) atoms. The Pr(2)-S(2) bond length is 2.91 Å. There is one shorter (3.02 Å) and one longer (3.07 Å) Pr(2)-S(3) bond length. There is one shorter (2.87 Å) and one longer (2.96 Å) Pr(2)-S(4) bond length. There are a spread of Pr(2)-S(1) bond distances ranging from 2.91-3.53 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 2.16 Å. The Si(1)-S(3) bond length is 2.11 Å. The Si(1)-S(4) bond length is 2.12 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded in a 4-coordinate geometry to three equivalent Pr(2) and one Si(1) atom. In the second S site, S(2) is bonded to one Pr(2), two equivalent Pr(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing SPr3Si tetrahedra. In the third S site, S(3) is bonded in a 4-coordinate geometry to one Pr(1), two equivalent Pr(2), and one Si(1) atom. In the fourth S site, S(4) is bonded in a 3-coordinate geometry to two equivalent Pr(2) and one Si(1) atom.