La6NiSi2S14 crystallizes in the trigonal P3 space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to one S(1), one S(6), two equivalent S(3), two equivalent S(4), and two equivalent S(5) atoms. In the second La site, La(2) is bonded in a 8-coordinate geometry to one S(2), one S(5), two equivalent S(3), two equivalent S(4), and two equivalent S(6) atoms. Ni(1) is bonded in an octahedral geometry to three equivalent S(3) and three equivalent S(4) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a tetrahedral geometry to one S(1) and three equivalent S(5) atoms. In the second Si site, Si(2) is bonded in a tetrahedral geometry to one S(2) and three equivalent S(6) atoms. There are six inequivalent S sites. In the first S site, S(1) is bonded to three equivalent La(1) and one Si(1) atom to form distorted corner-sharing SLa3Si tetrahedra. In the second S site, S(2) is bonded to three equivalent La(2) and one Si(2) atom to form distorted corner-sharing SLa3Si tetrahedra. In the third S site, S(3) is bonded to two equivalent La(1), two equivalent La(2), and one Ni(1) atom to form distorted SLa4Ni trigonal bipyramids that share corners with two equivalent S(1)La3Si tetrahedra, corners with two equivalent S(2)La3Si tetrahedra,  a cornercorner with one S(4)La4Ni trigonal bipyramid, corners with two equivalent S(3)La4Ni trigonal bipyramids, edges with two equivalent S(3)La4Ni trigonal bipyramids, edges with two equivalent S(4)La4Ni trigonal bipyramids, and faces with two equivalent S(4)La4Ni trigonal bipyramids. In the fourth S site, S(4) is bonded to two equivalent La(1), two equivalent La(2), and one Ni(1) atom to form distorted SLa4Ni trigonal bipyramids that share corners with two equivalent S(1)La3Si tetrahedra, corners with two equivalent S(2)La3Si tetrahedra,  a cornercorner with one S(3)La4Ni trigonal bipyramid, corners with two equivalent S(4)La4Ni trigonal bipyramids, edges with two equivalent S(3)La4Ni trigonal bipyramids, edges with two equivalent S(4)La4Ni trigonal bipyramids, and faces with two equivalent S(3)La4Ni trigonal bipyramids. In the fifth S site, S(5) is bonded in a distorted rectangular see-saw-like geometry to one La(2), two equivalent La(1), and one Si(1) atom. In the sixth S site, S(6) is bonded in a distorted rectangular see-saw-like geometry to one La(1), two equivalent La(2), and one Si(2) atom.
La6NiSi2S14 crystallizes in the trigonal P3 space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to one S(1), one S(6), two equivalent S(3), two equivalent S(4), and two equivalent S(5) atoms. The La(1)-S(1) bond length is 3.12 Å. The La(1)-S(6) bond length is 3.06 Å. There is one shorter (2.92 Å) and one longer (3.25 Å) La(1)-S(3) bond length. There is one shorter (2.82 Å) and one longer (2.86 Å) La(1)-S(4) bond length. There is one shorter (2.96 Å) and one longer (3.04 Å) La(1)-S(5) bond length. In the second La site, La(2) is bonded in a 8-coordinate geometry to one S(2), one S(5), two equivalent S(3), two equivalent S(4), and two equivalent S(6) atoms. The La(2)-S(2) bond length is 3.13 Å. The La(2)-S(5) bond length is 3.06 Å. Both La(2)-S(3) bond lengths are 2.84 Å. There is one shorter (3.03 Å) and one longer (3.13 Å) La(2)-S(4) bond length. There is one shorter (2.93 Å) and one longer (3.03 Å) La(2)-S(6) bond length. Ni(1) is bonded in an octahedral geometry to three equivalent S(3) and three equivalent S(4) atoms. All Ni(1)-S(3) bond lengths are 2.54 Å. All Ni(1)-S(4) bond lengths are 2.52 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a tetrahedral geometry to one S(1) and three equivalent S(5) atoms. The Si(1)-S(1) bond length is 2.10 Å. All Si(1)-S(5) bond lengths are 2.14 Å. In the second Si site, Si(2) is bonded in a tetrahedral geometry to one S(2) and three equivalent S(6) atoms. The Si(2)-S(2) bond length is 2.11 Å. All Si(2)-S(6) bond lengths are 2.14 Å. There are six inequivalent S sites. In the first S site, S(1) is bonded to three equivalent La(1) and one Si(1) atom to form distorted corner-sharing SLa3Si tetrahedra. In the second S site, S(2) is bonded to three equivalent La(2) and one Si(2) atom to form distorted corner-sharing SLa3Si tetrahedra. In the third S site, S(3) is bonded to two equivalent La(1), two equivalent La(2), and one Ni(1) atom to form distorted SLa4Ni trigonal bipyramids that share corners with two equivalent S(1)La3Si tetrahedra, corners with two equivalent S(2)La3Si tetrahedra,  a cornercorner with one S(4)La4Ni trigonal bipyramid, corners with two equivalent S(3)La4Ni trigonal bipyramids, edges with two equivalent S(3)La4Ni trigonal bipyramids, edges with two equivalent S(4)La4Ni trigonal bipyramids, and faces with two equivalent S(4)La4Ni trigonal bipyramids. In the fourth S site, S(4) is bonded to two equivalent La(1), two equivalent La(2), and one Ni(1) atom to form distorted SLa4Ni trigonal bipyramids that share corners with two equivalent S(1)La3Si tetrahedra, corners with two equivalent S(2)La3Si tetrahedra,  a cornercorner with one S(3)La4Ni trigonal bipyramid, corners with two equivalent S(4)La4Ni trigonal bipyramids, edges with two equivalent S(3)La4Ni trigonal bipyramids, edges with two equivalent S(4)La4Ni trigonal bipyramids, and faces with two equivalent S(3)La4Ni trigonal bipyramids. In the fifth S site, S(5) is bonded in a distorted rectangular see-saw-like geometry to one La(2), two equivalent La(1), and one Si(1) atom. In the sixth S site, S(6) is bonded in a distorted rectangular see-saw-like geometry to one La(1), two equivalent La(2), and one Si(2) atom.