LaYS3 crystallizes in the monoclinic P2_1/m space group. There are four inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to one S(11), one S(12), two equivalent S(3), two equivalent S(5), and two equivalent S(7) atoms. In the second La site, La(2) is bonded in a 8-coordinate geometry to one S(10), one S(4), two equivalent S(1), two equivalent S(6), and two equivalent S(7) atoms. In the third La site, La(3) is bonded in a 8-coordinate geometry to one S(10), one S(11), two equivalent S(2), two equivalent S(5), and two equivalent S(6) atoms. In the fourth La site, La(4) is bonded in a 8-coordinate geometry to one S(11), two equivalent S(2), two equivalent S(8), and three equivalent S(9) atoms. There are four inequivalent Y sites. In the first Y site, Y(1) is bonded to one S(3), two equivalent S(11), and three equivalent S(8) atoms to form a mixture of corner and edge-sharing YS6 octahedra. The corner-sharing octahedral tilt angles are 61°. In the second Y site, Y(2) is bonded to one S(2), one S(3), two equivalent S(10), and two equivalent S(9) atoms to form a mixture of corner and edge-sharing YS6 octahedra. The corner-sharing octahedral tilt angles are 61°. In the third Y site, Y(3) is bonded to one S(4), one S(7), two equivalent S(12), and three equivalent S(1) atoms to form a mixture of distorted corner, edge, and face-sharing YS7 pentagonal bipyramids. In the fourth Y site, Y(4) is bonded to one S(5), one S(6), two equivalent S(12), and three equivalent S(4) atoms to form a mixture of distorted corner, edge, and face-sharing YS7 pentagonal bipyramids. There are twelve inequivalent S sites. In the first S site, S(1) is bonded to two equivalent La(2) and three equivalent Y(3) atoms to form distorted SLa2Y3 trigonal bipyramids that share corners with four equivalent S(7)La4Y square pyramids, corners with two equivalent S(6)La4Y trigonal bipyramids, corners with four equivalent S(12)LaY4 trigonal bipyramids, corners with two equivalent S(10)La2Y2 trigonal pyramids,  an edgeedge with one S(6)La4Y trigonal bipyramid,  an edgeedge with one S(12)LaY4 trigonal bipyramid, edges with four equivalent S(1)La2Y3 trigonal bipyramids, and  a faceface with one S(7)La4Y square pyramid. In the second S site, S(2) is bonded to two equivalent La(3), two equivalent La(4), and one Y(2) atom to form distorted SLa4Y square pyramids that share corners with two equivalent S(8)La2Y3 square pyramids,  a cornercorner with one S(3)La2Y2 tetrahedra, corners with two equivalent S(9)La3Y2 trigonal bipyramids, corners with two equivalent S(5)La4Y trigonal bipyramids, corners with two equivalent S(6)La4Y trigonal bipyramids,  an edgeedge with one S(8)La2Y3 square pyramid, edges with two equivalent S(2)La4Y square pyramids,  an edgeedge with one S(5)La4Y trigonal bipyramid,  an edgeedge with one S(6)La4Y trigonal bipyramid, edges with three equivalent S(9)La3Y2 trigonal bipyramids, and edges with two equivalent S(10)La2Y2 trigonal pyramids. In the third S site, S(3) is bonded to two equivalent La(1), one Y(1), and one Y(2) atom to form SLa2Y2 tetrahedra that share  a cornercorner with one S(2)La4Y square pyramid, corners with two equivalent S(7)La4Y square pyramids, corners with three equivalent S(8)La2Y3 square pyramids, corners with two equivalent S(3)La2Y2 tetrahedra, corners with two equivalent S(9)La3Y2 trigonal bipyramids, corners with two equivalent S(5)La4Y trigonal bipyramids, corners with two equivalent S(12)LaY4 trigonal bipyramids, corners with two equivalent S(10)La2Y2 trigonal pyramids,  an edgeedge with one S(7)La4Y square pyramid, and  an edgeedge with one S(5)La4Y trigonal bipyramid. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to one La(2), one Y(3), and three equivalent Y(4) atoms. In the fifth S site, S(5) is bonded to two equivalent La(1), two equivalent La(3), and one Y(4) atom to form SLa4Y trigonal bipyramids that share corners with two equivalent S(2)La4Y square pyramids, corners with two equivalent S(7)La4Y square pyramids, corners with two equivalent S(3)La2Y2 tetrahedra, corners with two equivalent S(6)La4Y trigonal bipyramids, corners with two equivalent S(10)La2Y2 trigonal pyramids,  an edgeedge with one S(2)La4Y square pyramid,  an edgeedge with one S(7)La4Y square pyramid,  an edgeedge with one S(3)La2Y2 tetrahedra, edges with two equivalent S(5)La4Y trigonal bipyramids, edges with two equivalent S(12)LaY4 trigonal bipyramids, and  a faceface with one S(6)La4Y trigonal bipyramid. In the sixth S site, S(6) is bonded to two equivalent La(2), two equivalent La(3), and one Y(4) atom to form distorted SLa4Y trigonal bipyramids that share corners with two equivalent S(2)La4Y square pyramids, corners with two equivalent S(7)La4Y square pyramids, corners with two equivalent S(1)La2Y3 trigonal bipyramids, corners with two equivalent S(5)La4Y trigonal bipyramids, corners with two equivalent S(12)LaY4 trigonal bipyramids,  an edgeedge with one S(2)La4Y square pyramid,  an edgeedge with one S(7)La4Y square pyramid,  an edgeedge with one S(1)La2Y3 trigonal bipyramid, edges with two equivalent S(6)La4Y trigonal bipyramids, edges with two equivalent S(10)La2Y2 trigonal pyramids, and  a faceface with one S(5)La4Y trigonal bipyramid. In the seventh S site, S(7) is bonded to two equivalent La(1), two equivalent La(2), and one Y(3) atom to form distorted SLa4Y square pyramids that share corners with two equivalent S(3)La2Y2 tetrahedra, corners with two equivalent S(5)La4Y trigonal bipyramids, corners with two equivalent S(6)La4Y trigonal bipyramids, corners with four equivalent S(1)La2Y3 trigonal bipyramids, corners with two equivalent S(10)La2Y2 trigonal pyramids, edges with two equivalent S(7)La4Y square pyramids,  an edgeedge with one S(3)La2Y2 tetrahedra,  an edgeedge with one S(5)La4Y trigonal bipyramid,  an edgeedge with one S(6)La4Y trigonal bipyramid, edges with two equivalent S(12)LaY4 trigonal bipyramids, and  a faceface with one S(1)La2Y3 trigonal bipyramid. In the eighth S site, S(8) is bonded to two equivalent La(4) and three equivalent Y(1) atoms to form SLa2Y3 square pyramids that share corners with two equivalent S(2)La4Y square pyramids, corners with three equivalent S(3)La2Y2 tetrahedra, corners with four equivalent S(9)La3Y2 trigonal bipyramids,  an edgeedge with one S(2)La4Y square pyramid, edges with four equivalent S(8)La2Y3 square pyramids, and  an edgeedge with one S(9)La3Y2 trigonal bipyramid. In the ninth S site, S(9) is bonded to three equivalent La(4) and two equivalent Y(2) atoms to form distorted SLa3Y2 trigonal bipyramids that share corners with two equivalent S(2)La4Y square pyramids, corners with four equivalent S(8)La2Y3 square pyramids, corners with two equivalent S(3)La2Y2 tetrahedra, corners with two equivalent S(10)La2Y2 trigonal pyramids,  an edgeedge with one S(8)La2Y3 square pyramid, edges with three equivalent S(2)La4Y square pyramids, edges with four equivalent S(9)La3Y2 trigonal bipyramids, and  an edgeedge with one S(10)La2Y2 trigonal pyramid. In the tenth S site, S(10) is bonded to one La(2), one La(3), and two equivalent Y(2) atoms to form SLa2Y2 trigonal pyramids that share corners with two equivalent S(7)La4Y square pyramids, corners with two equivalent S(3)La2Y2 tetrahedra, corners with two equivalent S(1)La2Y3 trigonal bipyramids, corners with two equivalent S(9)La3Y2 trigonal bipyramids, corners with two equivalent S(5)La4Y trigonal bipyramids, corners with two equivalent S(10)La2Y2 trigonal pyramids, edges with two equivalent S(2)La4Y square pyramids,  an edgeedge with one S(9)La3Y2 trigonal bipyramid, and edges with two equivalent S(6)La4Y trigonal bipyramids. In the eleventh S site, S(11) is bonded in a 5-coordinate geometry to one La(1), one La(3), one La(4), and two equivalent Y(1) atoms. In the twelfth S site, S(12) is bonded to one La(1), two equivalent Y(3), and two equivalent Y(4) atoms to form distorted SLaY4 trigonal bipyramids that share corners with two equivalent S(3)La2Y2 tetrahedra, corners with two equivalent S(6)La4Y trigonal bipyramids, corners with four equivalent S(1)La2Y3 trigonal bipyramids, edges with two equivalent S(7)La4Y square pyramids,  an edgeedge with one S(1)La2Y3 trigonal bipyramid, edges with two equivalent S(5)La4Y trigonal bipyramids, and edges with two equivalent S(12)LaY4 trigonal bipyramids.
LaYS3 crystallizes in the monoclinic P2_1/m space group. There are four inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to one S(11), one S(12), two equivalent S(3), two equivalent S(5), and two equivalent S(7) atoms. The La(1)-S(11) bond length is 3.55 Å. The La(1)-S(12) bond length is 3.06 Å. Both La(1)-S(3) bond lengths are 2.93 Å. Both La(1)-S(5) bond lengths are 2.99 Å. Both La(1)-S(7) bond lengths are 3.02 Å. In the second La site, La(2) is bonded in a 8-coordinate geometry to one S(10), one S(4), two equivalent S(1), two equivalent S(6), and two equivalent S(7) atoms. The La(2)-S(10) bond length is 2.87 Å. The La(2)-S(4) bond length is 3.37 Å. Both La(2)-S(1) bond lengths are 2.97 Å. Both La(2)-S(6) bond lengths are 2.91 Å. Both La(2)-S(7) bond lengths are 3.10 Å. In the third La site, La(3) is bonded in a 8-coordinate geometry to one S(10), one S(11), two equivalent S(2), two equivalent S(5), and two equivalent S(6) atoms. The La(3)-S(10) bond length is 3.01 Å. The La(3)-S(11) bond length is 2.93 Å. Both La(3)-S(2) bond lengths are 3.00 Å. Both La(3)-S(5) bond lengths are 3.01 Å. Both La(3)-S(6) bond lengths are 3.02 Å. In the fourth La site, La(4) is bonded in a 8-coordinate geometry to one S(11), two equivalent S(2), two equivalent S(8), and three equivalent S(9) atoms. The La(4)-S(11) bond length is 3.18 Å. Both La(4)-S(2) bond lengths are 2.93 Å. Both La(4)-S(8) bond lengths are 3.01 Å. There is one shorter (2.98 Å) and two longer (3.07 Å) La(4)-S(9) bond lengths. There are four inequivalent Y sites. In the first Y site, Y(1) is bonded to one S(3), two equivalent S(11), and three equivalent S(8) atoms to form a mixture of corner and edge-sharing YS6 octahedra. The corner-sharing octahedral tilt angles are 61°. The Y(1)-S(3) bond length is 2.64 Å. Both Y(1)-S(11) bond lengths are 2.64 Å. There is one shorter (2.73 Å) and two longer (2.83 Å) Y(1)-S(8) bond lengths. In the second Y site, Y(2) is bonded to one S(2), one S(3), two equivalent S(10), and two equivalent S(9) atoms to form a mixture of corner and edge-sharing YS6 octahedra. The corner-sharing octahedral tilt angles are 61°. The Y(2)-S(2) bond length is 2.70 Å. The Y(2)-S(3) bond length is 2.68 Å. Both Y(2)-S(10) bond lengths are 2.67 Å. Both Y(2)-S(9) bond lengths are 2.83 Å. In the third Y site, Y(3) is bonded to one S(4), one S(7), two equivalent S(12), and three equivalent S(1) atoms to form a mixture of distorted corner, edge, and face-sharing YS7 pentagonal bipyramids. The Y(3)-S(4) bond length is 2.97 Å. The Y(3)-S(7) bond length is 2.73 Å. Both Y(3)-S(12) bond lengths are 2.80 Å. There are two shorter (2.77 Å) and one longer (2.93 Å) Y(3)-S(1) bond length. In the fourth Y site, Y(4) is bonded to one S(5), one S(6), two equivalent S(12), and three equivalent S(4) atoms to form a mixture of distorted corner, edge, and face-sharing YS7 pentagonal bipyramids. The Y(4)-S(5) bond length is 2.97 Å. The Y(4)-S(6) bond length is 2.82 Å. Both Y(4)-S(12) bond lengths are 2.89 Å. There are two shorter (2.74 Å) and one longer (2.91 Å) Y(4)-S(4) bond length. There are twelve inequivalent S sites. In the first S site, S(1) is bonded to two equivalent La(2) and three equivalent Y(3) atoms to form distorted SLa2Y3 trigonal bipyramids that share corners with four equivalent S(7)La4Y square pyramids, corners with two equivalent S(6)La4Y trigonal bipyramids, corners with four equivalent S(12)LaY4 trigonal bipyramids, corners with two equivalent S(10)La2Y2 trigonal pyramids,  an edgeedge with one S(6)La4Y trigonal bipyramid,  an edgeedge with one S(12)LaY4 trigonal bipyramid, edges with four equivalent S(1)La2Y3 trigonal bipyramids, and  a faceface with one S(7)La4Y square pyramid. In the second S site, S(2) is bonded to two equivalent La(3), two equivalent La(4), and one Y(2) atom to form distorted SLa4Y square pyramids that share corners with two equivalent S(8)La2Y3 square pyramids,  a cornercorner with one S(3)La2Y2 tetrahedra, corners with two equivalent S(9)La3Y2 trigonal bipyramids, corners with two equivalent S(5)La4Y trigonal bipyramids, corners with two equivalent S(6)La4Y trigonal bipyramids,  an edgeedge with one S(8)La2Y3 square pyramid, edges with two equivalent S(2)La4Y square pyramids,  an edgeedge with one S(5)La4Y trigonal bipyramid,  an edgeedge with one S(6)La4Y trigonal bipyramid, edges with three equivalent S(9)La3Y2 trigonal bipyramids, and edges with two equivalent S(10)La2Y2 trigonal pyramids. In the third S site, S(3) is bonded to two equivalent La(1), one Y(1), and one Y(2) atom to form SLa2Y2 tetrahedra that share  a cornercorner with one S(2)La4Y square pyramid, corners with two equivalent S(7)La4Y square pyramids, corners with three equivalent S(8)La2Y3 square pyramids, corners with two equivalent S(3)La2Y2 tetrahedra, corners with two equivalent S(9)La3Y2 trigonal bipyramids, corners with two equivalent S(5)La4Y trigonal bipyramids, corners with two equivalent S(12)LaY4 trigonal bipyramids, corners with two equivalent S(10)La2Y2 trigonal pyramids,  an edgeedge with one S(7)La4Y square pyramid, and  an edgeedge with one S(5)La4Y trigonal bipyramid. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to one La(2), one Y(3), and three equivalent Y(4) atoms. In the fifth S site, S(5) is bonded to two equivalent La(1), two equivalent La(3), and one Y(4) atom to form SLa4Y trigonal bipyramids that share corners with two equivalent S(2)La4Y square pyramids, corners with two equivalent S(7)La4Y square pyramids, corners with two equivalent S(3)La2Y2 tetrahedra, corners with two equivalent S(6)La4Y trigonal bipyramids, corners with two equivalent S(10)La2Y2 trigonal pyramids,  an edgeedge with one S(2)La4Y square pyramid,  an edgeedge with one S(7)La4Y square pyramid,  an edgeedge with one S(3)La2Y2 tetrahedra, edges with two equivalent S(5)La4Y trigonal bipyramids, edges with two equivalent S(12)LaY4 trigonal bipyramids, and  a faceface with one S(6)La4Y trigonal bipyramid. In the sixth S site, S(6) is bonded to two equivalent La(2), two equivalent La(3), and one Y(4) atom to form distorted SLa4Y trigonal bipyramids that share corners with two equivalent S(2)La4Y square pyramids, corners with two equivalent S(7)La4Y square pyramids, corners with two equivalent S(1)La2Y3 trigonal bipyramids, corners with two equivalent S(5)La4Y trigonal bipyramids, corners with two equivalent S(12)LaY4 trigonal bipyramids,  an edgeedge with one S(2)La4Y square pyramid,  an edgeedge with one S(7)La4Y square pyramid,  an edgeedge with one S(1)La2Y3 trigonal bipyramid, edges with two equivalent S(6)La4Y trigonal bipyramids, edges with two equivalent S(10)La2Y2 trigonal pyramids, and  a faceface with one S(5)La4Y trigonal bipyramid. In the seventh S site, S(7) is bonded to two equivalent La(1), two equivalent La(2), and one Y(3) atom to form distorted SLa4Y square pyramids that share corners with two equivalent S(3)La2Y2 tetrahedra, corners with two equivalent S(5)La4Y trigonal bipyramids, corners with two equivalent S(6)La4Y trigonal bipyramids, corners with four equivalent S(1)La2Y3 trigonal bipyramids, corners with two equivalent S(10)La2Y2 trigonal pyramids, edges with two equivalent S(7)La4Y square pyramids,  an edgeedge with one S(3)La2Y2 tetrahedra,  an edgeedge with one S(5)La4Y trigonal bipyramid,  an edgeedge with one S(6)La4Y trigonal bipyramid, edges with two equivalent S(12)LaY4 trigonal bipyramids, and  a faceface with one S(1)La2Y3 trigonal bipyramid. In the eighth S site, S(8) is bonded to two equivalent La(4) and three equivalent Y(1) atoms to form SLa2Y3 square pyramids that share corners with two equivalent S(2)La4Y square pyramids, corners with three equivalent S(3)La2Y2 tetrahedra, corners with four equivalent S(9)La3Y2 trigonal bipyramids,  an edgeedge with one S(2)La4Y square pyramid, edges with four equivalent S(8)La2Y3 square pyramids, and  an edgeedge with one S(9)La3Y2 trigonal bipyramid. In the ninth S site, S(9) is bonded to three equivalent La(4) and two equivalent Y(2) atoms to form distorted SLa3Y2 trigonal bipyramids that share corners with two equivalent S(2)La4Y square pyramids, corners with four equivalent S(8)La2Y3 square pyramids, corners with two equivalent S(3)La2Y2 tetrahedra, corners with two equivalent S(10)La2Y2 trigonal pyramids,  an edgeedge with one S(8)La2Y3 square pyramid, edges with three equivalent S(2)La4Y square pyramids, edges with four equivalent S(9)La3Y2 trigonal bipyramids, and  an edgeedge with one S(10)La2Y2 trigonal pyramid. In the tenth S site, S(10) is bonded to one La(2), one La(3), and two equivalent Y(2) atoms to form SLa2Y2 trigonal pyramids that share corners with two equivalent S(7)La4Y square pyramids, corners with two equivalent S(3)La2Y2 tetrahedra, corners with two equivalent S(1)La2Y3 trigonal bipyramids, corners with two equivalent S(9)La3Y2 trigonal bipyramids, corners with two equivalent S(5)La4Y trigonal bipyramids, corners with two equivalent S(10)La2Y2 trigonal pyramids, edges with two equivalent S(2)La4Y square pyramids,  an edgeedge with one S(9)La3Y2 trigonal bipyramid, and edges with two equivalent S(6)La4Y trigonal bipyramids. In the eleventh S site, S(11) is bonded in a 5-coordinate geometry to one La(1), one La(3), one La(4), and two equivalent Y(1) atoms. In the twelfth S site, S(12) is bonded to one La(1), two equivalent Y(3), and two equivalent Y(4) atoms to form distorted SLaY4 trigonal bipyramids that share corners with two equivalent S(3)La2Y2 tetrahedra, corners with two equivalent S(6)La4Y trigonal bipyramids, corners with four equivalent S(1)La2Y3 trigonal bipyramids, edges with two equivalent S(7)La4Y square pyramids,  an edgeedge with one S(1)La2Y3 trigonal bipyramid, edges with two equivalent S(5)La4Y trigonal bipyramids, and edges with two equivalent S(12)LaY4 trigonal bipyramids.