Nd2SiS5 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 9-coordinate geometry to one S(5), two equivalent S(1), two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms. In the second Nd site, Nd(2) is bonded in a 8-coordinate geometry to one S(1), one S(3), two equivalent S(2), two equivalent S(4), and two equivalent S(5) atoms. Si(1) is bonded in a tetrahedral geometry to one S(1), one S(2), one S(3), and one S(5) atom. There are five inequivalent S sites. In the first S site, S(1) is bonded in a distorted rectangular see-saw-like geometry to one Nd(2), two equivalent Nd(1), and one Si(1) atom. In the second S site, S(2) is bonded to two equivalent Nd(1), two equivalent Nd(2), and one Si(1) atom to form distorted SNd4Si trigonal bipyramids that share corners with five equivalent S(5)Nd3Si tetrahedra, corners with three equivalent S(4)Nd4 trigonal pyramids,  an edgeedge with one S(5)Nd3Si tetrahedra, edges with two equivalent S(2)Nd4Si trigonal bipyramids,  an edgeedge with one S(4)Nd4 trigonal pyramid, and  a faceface with one S(4)Nd4 trigonal pyramid. In the third S site, S(3) is bonded in a 4-coordinate geometry to one Nd(2), two equivalent Nd(1), and one Si(1) atom. In the fourth S site, S(4) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form SNd4 trigonal pyramids that share corners with four equivalent S(5)Nd3Si tetrahedra, corners with three equivalent S(2)Nd4Si trigonal bipyramids, corners with two equivalent S(4)Nd4 trigonal pyramids,  an edgeedge with one S(5)Nd3Si tetrahedra,  an edgeedge with one S(2)Nd4Si trigonal bipyramid,  an edgeedge with one S(4)Nd4 trigonal pyramid, and  a faceface with one S(2)Nd4Si trigonal bipyramid. In the fifth S site, S(5) is bonded to one Nd(1), two equivalent Nd(2), and one Si(1) atom to form distorted SNd3Si tetrahedra that share corners with five equivalent S(2)Nd4Si trigonal bipyramids, corners with four equivalent S(4)Nd4 trigonal pyramids,  an edgeedge with one S(5)Nd3Si tetrahedra,  an edgeedge with one S(2)Nd4Si trigonal bipyramid, and  an edgeedge with one S(4)Nd4 trigonal pyramid.
Nd2SiS5 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 9-coordinate geometry to one S(5), two equivalent S(1), two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms. The Nd(1)-S(5) bond length is 2.89 Å. There is one shorter (3.03 Å) and one longer (3.11 Å) Nd(1)-S(1) bond length. There is one shorter (3.06 Å) and one longer (3.25 Å) Nd(1)-S(2) bond length. There is one shorter (3.08 Å) and one longer (3.35 Å) Nd(1)-S(3) bond length. There is one shorter (2.87 Å) and one longer (2.94 Å) Nd(1)-S(4) bond length. In the second Nd site, Nd(2) is bonded in a 8-coordinate geometry to one S(1), one S(3), two equivalent S(2), two equivalent S(4), and two equivalent S(5) atoms. The Nd(2)-S(1) bond length is 2.93 Å. The Nd(2)-S(3) bond length is 3.10 Å. There is one shorter (2.98 Å) and one longer (3.00 Å) Nd(2)-S(2) bond length. There is one shorter (2.81 Å) and one longer (2.82 Å) Nd(2)-S(4) bond length. There is one shorter (2.89 Å) and one longer (2.94 Å) Nd(2)-S(5) bond length. Si(1) is bonded in a tetrahedral geometry to one S(1), one S(2), one S(3), and one S(5) atom. The Si(1)-S(1) bond length is 2.12 Å. The Si(1)-S(2) bond length is 2.15 Å. The Si(1)-S(3) bond length is 2.10 Å. The Si(1)-S(5) bond length is 2.10 Å. There are five inequivalent S sites. In the first S site, S(1) is bonded in a distorted rectangular see-saw-like geometry to one Nd(2), two equivalent Nd(1), and one Si(1) atom. In the second S site, S(2) is bonded to two equivalent Nd(1), two equivalent Nd(2), and one Si(1) atom to form distorted SNd4Si trigonal bipyramids that share corners with five equivalent S(5)Nd3Si tetrahedra, corners with three equivalent S(4)Nd4 trigonal pyramids,  an edgeedge with one S(5)Nd3Si tetrahedra, edges with two equivalent S(2)Nd4Si trigonal bipyramids,  an edgeedge with one S(4)Nd4 trigonal pyramid, and  a faceface with one S(4)Nd4 trigonal pyramid. In the third S site, S(3) is bonded in a 4-coordinate geometry to one Nd(2), two equivalent Nd(1), and one Si(1) atom. In the fourth S site, S(4) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form SNd4 trigonal pyramids that share corners with four equivalent S(5)Nd3Si tetrahedra, corners with three equivalent S(2)Nd4Si trigonal bipyramids, corners with two equivalent S(4)Nd4 trigonal pyramids,  an edgeedge with one S(5)Nd3Si tetrahedra,  an edgeedge with one S(2)Nd4Si trigonal bipyramid,  an edgeedge with one S(4)Nd4 trigonal pyramid, and  a faceface with one S(2)Nd4Si trigonal bipyramid. In the fifth S site, S(5) is bonded to one Nd(1), two equivalent Nd(2), and one Si(1) atom to form distorted SNd3Si tetrahedra that share corners with five equivalent S(2)Nd4Si trigonal bipyramids, corners with four equivalent S(4)Nd4 trigonal pyramids,  an edgeedge with one S(5)Nd3Si tetrahedra,  an edgeedge with one S(2)Nd4Si trigonal bipyramid, and  an edgeedge with one S(4)Nd4 trigonal pyramid.