The compound described by Sr(La2Se3)4 crystallizes in the monoclinic Cc space group. Sr(1) is bonded to one Se(1), one Se(10), one Se(12), one Se(2), one Se(3), one Se(4), one Se(7), and one Se(8) atom to form distorted SrSe8 hexagonal bipyramids that share  a cornercorner with one La(3)Se8 hexagonal bipyramid,  a cornercorner with one La(4)Se8 hexagonal bipyramid,  a cornercorner with one La(6)Se8 hexagonal bipyramid,  a cornercorner with one La(7)Se8 hexagonal bipyramid, corners with two equivalent La(2)Se8 hexagonal bipyramids, corners with two equivalent La(8)Se8 hexagonal bipyramids,  an edgeedge with one La(3)Se8 hexagonal bipyramid,  an edgeedge with one La(7)Se8 hexagonal bipyramid, edges with two equivalent La(1)Se8 hexagonal bipyramids,  a faceface with one La(2)Se8 hexagonal bipyramid,  a faceface with one La(3)Se8 hexagonal bipyramid,  a faceface with one La(4)Se8 hexagonal bipyramid,  a faceface with one La(6)Se8 hexagonal bipyramid,  a faceface with one La(7)Se8 hexagonal bipyramid,  a faceface with one La(8)Se8 hexagonal bipyramid, and faces with two equivalent La(5)Se8 hexagonal bipyramids. There are eight inequivalent La sites. In the first La site, La(1) is bonded to one Se(1), one Se(10), one Se(11), one Se(12), one Se(3), one Se(5), one Se(6), and one Se(9) atom to form distorted LaSe8 hexagonal bipyramids that share  a cornercorner with one La(3)Se8 hexagonal bipyramid,  a cornercorner with one La(4)Se8 hexagonal bipyramid,  a cornercorner with one La(6)Se8 hexagonal bipyramid,  a cornercorner with one La(7)Se8 hexagonal bipyramid, corners with two equivalent La(2)Se8 hexagonal bipyramids, corners with two equivalent La(8)Se8 hexagonal bipyramids,  an edgeedge with one La(4)Se8 hexagonal bipyramid,  an edgeedge with one La(6)Se8 hexagonal bipyramid, edges with two equivalent Sr(1)Se8 hexagonal bipyramids,  a faceface with one La(2)Se8 hexagonal bipyramid,  a faceface with one La(3)Se8 hexagonal bipyramid,  a faceface with one La(4)Se8 hexagonal bipyramid,  a faceface with one La(6)Se8 hexagonal bipyramid,  a faceface with one La(7)Se8 hexagonal bipyramid,  a faceface with one La(8)Se8 hexagonal bipyramid, and faces with two equivalent La(5)Se8 hexagonal bipyramids. In the second La site, La(2) is bonded to one Se(1), one Se(11), one Se(2), one Se(3), one Se(4), one Se(5), one Se(6), and one Se(8) atom to form distorted LaSe8 hexagonal bipyramids that share corners with two equivalent Sr(1)Se8 hexagonal bipyramids, corners with two equivalent La(1)Se8 hexagonal bipyramids, corners with two equivalent La(3)Se8 hexagonal bipyramids, corners with two equivalent La(6)Se8 hexagonal bipyramids, edges with two equivalent La(5)Se8 hexagonal bipyramids, edges with two equivalent La(8)Se8 hexagonal bipyramids,  a faceface with one Sr(1)Se8 hexagonal bipyramid,  a faceface with one La(1)Se8 hexagonal bipyramid,  a faceface with one La(3)Se8 hexagonal bipyramid,  a faceface with one La(6)Se8 hexagonal bipyramid, faces with two equivalent La(4)Se8 hexagonal bipyramids, and faces with two equivalent La(7)Se8 hexagonal bipyramids. In the third La site, La(3) is bonded to one Se(10), one Se(2), one Se(3), one Se(4), one Se(6), one Se(7), one Se(8), and one Se(9) atom to form distorted LaSe8 hexagonal bipyramids that share  a cornercorner with one Sr(1)Se8 hexagonal bipyramid,  a cornercorner with one La(1)Se8 hexagonal bipyramid,  a cornercorner with one La(4)Se8 hexagonal bipyramid,  a cornercorner with one La(7)Se8 hexagonal bipyramid, corners with two equivalent La(2)Se8 hexagonal bipyramids, corners with two equivalent La(5)Se8 hexagonal bipyramids,  an edgeedge with one Sr(1)Se8 hexagonal bipyramid,  an edgeedge with one La(4)Se8 hexagonal bipyramid, edges with two equivalent La(6)Se8 hexagonal bipyramids,  a faceface with one Sr(1)Se8 hexagonal bipyramid,  a faceface with one La(1)Se8 hexagonal bipyramid,  a faceface with one La(2)Se8 hexagonal bipyramid,  a faceface with one La(4)Se8 hexagonal bipyramid,  a faceface with one La(5)Se8 hexagonal bipyramid,  a faceface with one La(7)Se8 hexagonal bipyramid, and faces with two equivalent La(8)Se8 hexagonal bipyramids. In the fourth La site, La(4) is bonded to one Se(10), one Se(11), one Se(3), one Se(4), one Se(5), one Se(6), one Se(8), and one Se(9) atom to form distorted LaSe8 hexagonal bipyramids that share  a cornercorner with one Sr(1)Se8 hexagonal bipyramid,  a cornercorner with one La(1)Se8 hexagonal bipyramid,  a cornercorner with one La(3)Se8 hexagonal bipyramid,  a cornercorner with one La(6)Se8 hexagonal bipyramid, corners with two equivalent La(5)Se8 hexagonal bipyramids, corners with two equivalent La(8)Se8 hexagonal bipyramids,  an edgeedge with one La(1)Se8 hexagonal bipyramid,  an edgeedge with one La(3)Se8 hexagonal bipyramid, edges with two equivalent La(7)Se8 hexagonal bipyramids,  a faceface with one Sr(1)Se8 hexagonal bipyramid,  a faceface with one La(1)Se8 hexagonal bipyramid,  a faceface with one La(3)Se8 hexagonal bipyramid,  a faceface with one La(5)Se8 hexagonal bipyramid,  a faceface with one La(6)Se8 hexagonal bipyramid,  a faceface with one La(8)Se8 hexagonal bipyramid, and faces with two equivalent La(2)Se8 hexagonal bipyramids. In the fifth La site, La(5) is bonded to one Se(1), one Se(10), one Se(12), one Se(3), one Se(4), one Se(5), one Se(7), and one Se(9) atom to form distorted LaSe8 hexagonal bipyramids that share corners with two equivalent La(3)Se8 hexagonal bipyramids, corners with two equivalent La(4)Se8 hexagonal bipyramids, corners with two equivalent La(6)Se8 hexagonal bipyramids, corners with two equivalent La(7)Se8 hexagonal bipyramids, edges with two equivalent La(2)Se8 hexagonal bipyramids, edges with two equivalent La(8)Se8 hexagonal bipyramids,  a faceface with one La(3)Se8 hexagonal bipyramid,  a faceface with one La(4)Se8 hexagonal bipyramid,  a faceface with one La(6)Se8 hexagonal bipyramid,  a faceface with one La(7)Se8 hexagonal bipyramid, faces with two equivalent Sr(1)Se8 hexagonal bipyramids, and faces with two equivalent La(1)Se8 hexagonal bipyramids. In the sixth La site, La(6) is bonded to one Se(1), one Se(11), one Se(12), one Se(2), one Se(5), one Se(6), one Se(7), and one Se(9) atom to form distorted LaSe8 hexagonal bipyramids that share  a cornercorner with one Sr(1)Se8 hexagonal bipyramid,  a cornercorner with one La(1)Se8 hexagonal bipyramid,  a cornercorner with one La(4)Se8 hexagonal bipyramid,  a cornercorner with one La(7)Se8 hexagonal bipyramid, corners with two equivalent La(2)Se8 hexagonal bipyramids, corners with two equivalent La(5)Se8 hexagonal bipyramids,  an edgeedge with one La(1)Se8 hexagonal bipyramid,  an edgeedge with one La(7)Se8 hexagonal bipyramid, edges with two equivalent La(3)Se8 hexagonal bipyramids,  a faceface with one Sr(1)Se8 hexagonal bipyramid,  a faceface with one La(1)Se8 hexagonal bipyramid,  a faceface with one La(2)Se8 hexagonal bipyramid,  a faceface with one La(4)Se8 hexagonal bipyramid,  a faceface with one La(5)Se8 hexagonal bipyramid,  a faceface with one La(7)Se8 hexagonal bipyramid, and faces with two equivalent La(8)Se8 hexagonal bipyramids. In the seventh La site, La(7) is bonded to one Se(1), one Se(11), one Se(12), one Se(2), one Se(4), one Se(5), one Se(7), and one Se(8) atom to form distorted LaSe8 hexagonal bipyramids that share  a cornercorner with one Sr(1)Se8 hexagonal bipyramid,  a cornercorner with one La(1)Se8 hexagonal bipyramid,  a cornercorner with one La(3)Se8 hexagonal bipyramid,  a cornercorner with one La(6)Se8 hexagonal bipyramid, corners with two equivalent La(5)Se8 hexagonal bipyramids, corners with two equivalent La(8)Se8 hexagonal bipyramids,  an edgeedge with one Sr(1)Se8 hexagonal bipyramid,  an edgeedge with one La(6)Se8 hexagonal bipyramid, edges with two equivalent La(4)Se8 hexagonal bipyramids,  a faceface with one Sr(1)Se8 hexagonal bipyramid,  a faceface with one La(1)Se8 hexagonal bipyramid,  a faceface with one La(3)Se8 hexagonal bipyramid,  a faceface with one La(5)Se8 hexagonal bipyramid,  a faceface with one La(6)Se8 hexagonal bipyramid,  a faceface with one La(8)Se8 hexagonal bipyramid, and faces with two equivalent La(2)Se8 hexagonal bipyramids. In the eighth La site, La(8) is bonded to one Se(10), one Se(11), one Se(12), one Se(2), one Se(6), one Se(7), one Se(8), and one Se(9) atom to form distorted LaSe8 hexagonal bipyramids that share corners with two equivalent Sr(1)Se8 hexagonal bipyramids, corners with two equivalent La(1)Se8 hexagonal bipyramids, corners with two equivalent La(4)Se8 hexagonal bipyramids, corners with two equivalent La(7)Se8 hexagonal bipyramids, edges with two equivalent La(2)Se8 hexagonal bipyramids, edges with two equivalent La(5)Se8 hexagonal bipyramids,  a faceface with one Sr(1)Se8 hexagonal bipyramid,  a faceface with one La(1)Se8 hexagonal bipyramid,  a faceface with one La(4)Se8 hexagonal bipyramid,  a faceface with one La(7)Se8 hexagonal bipyramid, faces with two equivalent La(3)Se8 hexagonal bipyramids, and faces with two equivalent La(6)Se8 hexagonal bipyramids. There are twelve inequivalent Se sites. In the first Se site, Se(1) is bonded to one Sr(1), one La(1), one La(2), one La(5), one La(6), and one La(7) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(11)La6 octahedra,  a cornercorner with one Se(6)La6 octahedra,  a cornercorner with one Se(9)La6 octahedra,  a cornercorner with one Se(3)SrLa5 octahedra,  a cornercorner with one Se(7)SrLa5 octahedra,  a cornercorner with one Se(8)SrLa5 octahedra, corners with two equivalent Se(12)SrLa5 octahedra, corners with two equivalent Se(2)SrLa5 octahedra, corners with two equivalent Se(4)SrLa5 octahedra, corners with three equivalent Se(10)SrLa5 octahedra,  an edgeedge with one Se(5)La6 octahedra,  an edgeedge with one Se(6)La6 octahedra,  an edgeedge with one Se(9)La6 octahedra,  an edgeedge with one Se(2)SrLa5 octahedra,  an edgeedge with one Se(4)SrLa5 octahedra,  an edgeedge with one Se(8)SrLa5 octahedra,  a faceface with one Se(11)La6 octahedra,  a faceface with one Se(5)La6 octahedra,  a faceface with one Se(12)SrLa5 octahedra,  a faceface with one Se(3)SrLa5 octahedra, and  a faceface with one Se(7)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the second Se site, Se(2) is bonded to one Sr(1), one La(2), one La(3), one La(6), one La(7), and one La(8) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(6)La6 octahedra,  a cornercorner with one Se(3)SrLa5 octahedra, corners with two equivalent Se(11)La6 octahedra, corners with two equivalent Se(1)SrLa5 octahedra, corners with two equivalent Se(12)SrLa5 octahedra, corners with two equivalent Se(4)SrLa5 octahedra, corners with two equivalent Se(7)SrLa5 octahedra, corners with three equivalent Se(9)La6 octahedra,  an edgeedge with one Se(11)La6 octahedra,  an edgeedge with one Se(1)SrLa5 octahedra,  an edgeedge with one Se(12)SrLa5 octahedra,  an edgeedge with one Se(3)SrLa5 octahedra,  an edgeedge with one Se(4)SrLa5 octahedra,  an edgeedge with one Se(8)SrLa5 octahedra,  a faceface with one Se(5)La6 octahedra,  a faceface with one Se(6)La6 octahedra,  a faceface with one Se(10)SrLa5 octahedra,  a faceface with one Se(7)SrLa5 octahedra, and  a faceface with one Se(8)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the third Se site, Se(3) is bonded to one Sr(1), one La(1), one La(2), one La(3), one La(4), and one La(5) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(11)La6 octahedra,  a cornercorner with one Se(9)La6 octahedra,  a cornercorner with one Se(1)SrLa5 octahedra,  a cornercorner with one Se(2)SrLa5 octahedra,  a cornercorner with one Se(7)SrLa5 octahedra,  a cornercorner with one Se(8)SrLa5 octahedra, corners with two equivalent Se(5)La6 octahedra, corners with two equivalent Se(6)La6 octahedra, corners with two equivalent Se(10)SrLa5 octahedra, corners with three equivalent Se(12)SrLa5 octahedra,  an edgeedge with one Se(11)La6 octahedra,  an edgeedge with one Se(5)La6 octahedra,  an edgeedge with one Se(6)La6 octahedra,  an edgeedge with one Se(2)SrLa5 octahedra,  an edgeedge with one Se(4)SrLa5 octahedra,  an edgeedge with one Se(7)SrLa5 octahedra,  a faceface with one Se(9)La6 octahedra,  a faceface with one Se(1)SrLa5 octahedra,  a faceface with one Se(10)SrLa5 octahedra,  a faceface with one Se(4)SrLa5 octahedra, and  a faceface with one Se(8)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the fourth Se site, Se(4) is bonded to one Sr(1), one La(2), one La(3), one La(4), one La(5), and one La(7) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(5)La6 octahedra,  a cornercorner with one Se(9)La6 octahedra, corners with two equivalent Se(1)SrLa5 octahedra, corners with two equivalent Se(10)SrLa5 octahedra, corners with two equivalent Se(2)SrLa5 octahedra, corners with two equivalent Se(7)SrLa5 octahedra, corners with two equivalent Se(8)SrLa5 octahedra, corners with three equivalent Se(11)La6 octahedra,  an edgeedge with one Se(9)La6 octahedra,  an edgeedge with one Se(1)SrLa5 octahedra,  an edgeedge with one Se(10)SrLa5 octahedra,  an edgeedge with one Se(2)SrLa5 octahedra,  an edgeedge with one Se(3)SrLa5 octahedra,  an edgeedge with one Se(7)SrLa5 octahedra,  a faceface with one Se(5)La6 octahedra,  a faceface with one Se(6)La6 octahedra,  a faceface with one Se(12)SrLa5 octahedra,  a faceface with one Se(3)SrLa5 octahedra, and  a faceface with one Se(8)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-51°. In the fifth Se site, Se(5) is bonded to one La(1), one La(2), one La(4), one La(5), one La(6), and one La(7) atom to form distorted SeLa6 octahedra that share  a cornercorner with one Se(4)SrLa5 octahedra,  a cornercorner with one Se(7)SrLa5 octahedra, corners with two equivalent Se(11)La6 octahedra, corners with two equivalent Se(6)La6 octahedra, corners with two equivalent Se(9)La6 octahedra, corners with two equivalent Se(12)SrLa5 octahedra, corners with two equivalent Se(3)SrLa5 octahedra, corners with three equivalent Se(8)SrLa5 octahedra,  an edgeedge with one Se(6)La6 octahedra,  an edgeedge with one Se(9)La6 octahedra,  an edgeedge with one Se(1)SrLa5 octahedra,  an edgeedge with one Se(12)SrLa5 octahedra,  an edgeedge with one Se(3)SrLa5 octahedra,  an edgeedge with one Se(7)SrLa5 octahedra,  a faceface with one Se(11)La6 octahedra,  a faceface with one Se(1)SrLa5 octahedra,  a faceface with one Se(10)SrLa5 octahedra,  a faceface with one Se(2)SrLa5 octahedra, and  a faceface with one Se(4)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the sixth Se site, Se(6) is bonded to one La(1), one La(2), one La(3), one La(4), one La(6), and one La(8) atom to form distorted SeLa6 octahedra that share  a cornercorner with one Se(1)SrLa5 octahedra,  a cornercorner with one Se(2)SrLa5 octahedra, corners with two equivalent Se(5)La6 octahedra, corners with two equivalent Se(9)La6 octahedra, corners with two equivalent Se(10)SrLa5 octahedra, corners with two equivalent Se(3)SrLa5 octahedra, corners with two equivalent Se(8)SrLa5 octahedra, corners with three equivalent Se(7)SrLa5 octahedra,  an edgeedge with one Se(11)La6 octahedra,  an edgeedge with one Se(5)La6 octahedra,  an edgeedge with one Se(1)SrLa5 octahedra,  an edgeedge with one Se(10)SrLa5 octahedra,  an edgeedge with one Se(3)SrLa5 octahedra,  an edgeedge with one Se(8)SrLa5 octahedra,  a faceface with one Se(11)La6 octahedra,  a faceface with one Se(9)La6 octahedra,  a faceface with one Se(12)SrLa5 octahedra,  a faceface with one Se(2)SrLa5 octahedra, and  a faceface with one Se(4)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the seventh Se site, Se(7) is bonded to one Sr(1), one La(3), one La(5), one La(6), one La(7), and one La(8) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(11)La6 octahedra,  a cornercorner with one Se(5)La6 octahedra,  a cornercorner with one Se(9)La6 octahedra,  a cornercorner with one Se(1)SrLa5 octahedra,  a cornercorner with one Se(3)SrLa5 octahedra,  a cornercorner with one Se(8)SrLa5 octahedra, corners with two equivalent Se(10)SrLa5 octahedra, corners with two equivalent Se(2)SrLa5 octahedra, corners with two equivalent Se(4)SrLa5 octahedra, corners with three equivalent Se(6)La6 octahedra,  an edgeedge with one Se(11)La6 octahedra,  an edgeedge with one Se(5)La6 octahedra,  an edgeedge with one Se(10)SrLa5 octahedra,  an edgeedge with one Se(12)SrLa5 octahedra,  an edgeedge with one Se(3)SrLa5 octahedra,  an edgeedge with one Se(4)SrLa5 octahedra,  a faceface with one Se(9)La6 octahedra,  a faceface with one Se(1)SrLa5 octahedra,  a faceface with one Se(12)SrLa5 octahedra,  a faceface with one Se(2)SrLa5 octahedra, and  a faceface with one Se(8)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the eighth Se site, Se(8) is bonded to one Sr(1), one La(2), one La(3), one La(4), one La(7), and one La(8) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(11)La6 octahedra,  a cornercorner with one Se(9)La6 octahedra,  a cornercorner with one Se(1)SrLa5 octahedra,  a cornercorner with one Se(12)SrLa5 octahedra,  a cornercorner with one Se(3)SrLa5 octahedra,  a cornercorner with one Se(7)SrLa5 octahedra, corners with two equivalent Se(6)La6 octahedra, corners with two equivalent Se(10)SrLa5 octahedra, corners with two equivalent Se(4)SrLa5 octahedra, corners with three equivalent Se(5)La6 octahedra,  an edgeedge with one Se(6)La6 octahedra,  an edgeedge with one Se(9)La6 octahedra,  an edgeedge with one Se(1)SrLa5 octahedra,  an edgeedge with one Se(10)SrLa5 octahedra,  an edgeedge with one Se(12)SrLa5 octahedra,  an edgeedge with one Se(2)SrLa5 octahedra,  a faceface with one Se(11)La6 octahedra,  a faceface with one Se(2)SrLa5 octahedra,  a faceface with one Se(3)SrLa5 octahedra,  a faceface with one Se(4)SrLa5 octahedra, and  a faceface with one Se(7)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the ninth Se site, Se(9) is bonded to one La(1), one La(3), one La(4), one La(5), one La(6), and one La(8) atom to form distorted SeLa6 octahedra that share  a cornercorner with one Se(11)La6 octahedra,  a cornercorner with one Se(1)SrLa5 octahedra,  a cornercorner with one Se(3)SrLa5 octahedra,  a cornercorner with one Se(4)SrLa5 octahedra,  a cornercorner with one Se(7)SrLa5 octahedra,  a cornercorner with one Se(8)SrLa5 octahedra, corners with two equivalent Se(5)La6 octahedra, corners with two equivalent Se(6)La6 octahedra, corners with two equivalent Se(12)SrLa5 octahedra, corners with three equivalent Se(2)SrLa5 octahedra,  an edgeedge with one Se(5)La6 octahedra,  an edgeedge with one Se(1)SrLa5 octahedra,  an edgeedge with one Se(10)SrLa5 octahedra,  an edgeedge with one Se(12)SrLa5 octahedra,  an edgeedge with one Se(4)SrLa5 octahedra,  an edgeedge with one Se(8)SrLa5 octahedra,  a faceface with one Se(11)La6 octahedra,  a faceface with one Se(6)La6 octahedra,  a faceface with one Se(10)SrLa5 octahedra,  a faceface with one Se(3)SrLa5 octahedra, and  a faceface with one Se(7)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the tenth Se site, Se(10) is bonded to one Sr(1), one La(1), one La(3), one La(4), one La(5), and one La(8) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(11)La6 octahedra,  a cornercorner with one Se(12)SrLa5 octahedra, corners with two equivalent Se(6)La6 octahedra, corners with two equivalent Se(3)SrLa5 octahedra, corners with two equivalent Se(4)SrLa5 octahedra, corners with two equivalent Se(7)SrLa5 octahedra, corners with two equivalent Se(8)SrLa5 octahedra, corners with three equivalent Se(1)SrLa5 octahedra,  an edgeedge with one Se(11)La6 octahedra,  an edgeedge with one Se(6)La6 octahedra,  an edgeedge with one Se(9)La6 octahedra,  an edgeedge with one Se(4)SrLa5 octahedra,  an edgeedge with one Se(7)SrLa5 octahedra,  an edgeedge with one Se(8)SrLa5 octahedra,  a faceface with one Se(5)La6 octahedra,  a faceface with one Se(9)La6 octahedra,  a faceface with one Se(12)SrLa5 octahedra,  a faceface with one Se(2)SrLa5 octahedra, and  a faceface with one Se(3)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-51°. In the eleventh Se site, Se(11) is bonded to one La(1), one La(2), one La(4), one La(6), one La(7), and one La(8) atom to form distorted SeLa6 octahedra that share  a cornercorner with one Se(9)La6 octahedra,  a cornercorner with one Se(1)SrLa5 octahedra,  a cornercorner with one Se(10)SrLa5 octahedra,  a cornercorner with one Se(3)SrLa5 octahedra,  a cornercorner with one Se(7)SrLa5 octahedra,  a cornercorner with one Se(8)SrLa5 octahedra, corners with two equivalent Se(5)La6 octahedra, corners with two equivalent Se(12)SrLa5 octahedra, corners with two equivalent Se(2)SrLa5 octahedra, corners with three equivalent Se(4)SrLa5 octahedra,  an edgeedge with one Se(6)La6 octahedra,  an edgeedge with one Se(10)SrLa5 octahedra,  an edgeedge with one Se(12)SrLa5 octahedra,  an edgeedge with one Se(2)SrLa5 octahedra,  an edgeedge with one Se(3)SrLa5 octahedra,  an edgeedge with one Se(7)SrLa5 octahedra,  a faceface with one Se(5)La6 octahedra,  a faceface with one Se(6)La6 octahedra,  a faceface with one Se(9)La6 octahedra,  a faceface with one Se(1)SrLa5 octahedra, and  a faceface with one Se(8)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the twelfth Se site, Se(12) is bonded to one Sr(1), one La(1), one La(5), one La(6), one La(7), and one La(8) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(10)SrLa5 octahedra,  a cornercorner with one Se(8)SrLa5 octahedra, corners with two equivalent Se(11)La6 octahedra, corners with two equivalent Se(5)La6 octahedra, corners with two equivalent Se(9)La6 octahedra, corners with two equivalent Se(1)SrLa5 octahedra, corners with two equivalent Se(2)SrLa5 octahedra, corners with three equivalent Se(3)SrLa5 octahedra,  an edgeedge with one Se(11)La6 octahedra,  an edgeedge with one Se(5)La6 octahedra,  an edgeedge with one Se(9)La6 octahedra,  an edgeedge with one Se(2)SrLa5 octahedra,  an edgeedge with one Se(7)SrLa5 octahedra,  an edgeedge with one Se(8)SrLa5 octahedra,  a faceface with one Se(6)La6 octahedra,  a faceface with one Se(1)SrLa5 octahedra,  a faceface with one Se(10)SrLa5 octahedra,  a faceface with one Se(4)SrLa5 octahedra, and  a faceface with one Se(7)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. is represented by the CIF card [CIF]
data_Sr(La2Se3)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.125
_cell_length_b   9.125
_cell_length_c   15.142
_cell_angle_alpha   72.476
_cell_angle_beta   72.476
_cell_angle_gamma   90.023
_symmetry_Int_Tables_number   1
_cell_volume   1140.667
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Sr  Sr0  1  0.125  0.750  0.500  1.0
  Sr  Sr1  1  0.750  0.125  1.000  1.0
  La  La2  1  0.250  0.373  1.000  1.0
  La  La3  1  0.458  0.710  0.083  1.0
  La  La4  1  0.042  0.917  0.167  1.0
  La  La5  1  0.083  0.458  0.334  1.0
  La  La6  1  0.375  0.125  0.250  1.0
  La  La7  1  0.792  0.415  0.166  1.0
  La  La8  1  0.582  0.709  0.333  1.0
  La  La9  1  0.793  0.041  0.416  1.0
  La  La10  1  0.373  0.250  0.500  1.0
  La  La11  1  0.415  0.792  0.666  1.0
  La  La12  1  0.710  0.458  0.583  1.0
  La  La13  1  0.917  0.042  0.667  1.0
  La  La14  1  0.125  0.375  0.750  1.0
  La  La15  1  0.709  0.582  0.833  1.0
  La  La16  1  0.041  0.793  0.916  1.0
  La  La17  1  0.458  0.083  0.834  1.0
  Se  Se18  1  0.547  0.403  0.051  1.0
  Se  Se19  1  0.767  0.762  0.118  1.0
  Se  Se20  1  0.396  0.049  0.050  1.0
  Se  Se21  1  0.285  0.784  0.280  1.0
  Se  Se22  1  0.434  0.433  0.284  1.0
  Se  Se23  1  0.118  0.617  0.116  1.0
  Se  Se24  1  0.716  0.066  0.219  1.0
  Se  Se25  1  0.880  0.733  0.382  1.0
  Se  Se26  1  0.066  0.217  0.217  1.0
  Se  Se27  1  0.100  0.104  0.449  1.0
  Se  Se28  1  0.733  0.383  0.383  1.0
  Se  Se29  1  0.617  0.118  0.616  1.0
  Se  Se30  1  0.762  0.767  0.618  1.0
  Se  Se31  1  0.454  0.952  0.450  1.0
  Se  Se32  1  0.049  0.396  0.550  1.0
  Se  Se33  1  0.217  0.066  0.717  1.0
  Se  Se34  1  0.403  0.547  0.551  1.0
  Se  Se35  1  0.433  0.434  0.784  1.0
  Se  Se36  1  0.066  0.716  0.719  1.0
  Se  Se37  1  0.952  0.454  0.950  1.0
  Se  Se38  1  0.104  0.100  0.949  1.0
  Se  Se39  1  0.383  0.733  0.883  1.0
  Se  Se40  1  0.784  0.285  0.780  1.0
  Se  Se41  1  0.733  0.880  0.882  1.0
[/CIF]
.
The compound described by Sr(La2Se3)4 crystallizes in the monoclinic Cc space group. Sr(1) is bonded to one Se(1), one Se(10), one Se(12), one Se(2), one Se(3), one Se(4), one Se(7), and one Se(8) atom to form distorted SrSe8 hexagonal bipyramids that share  a cornercorner with one La(3)Se8 hexagonal bipyramid,  a cornercorner with one La(4)Se8 hexagonal bipyramid,  a cornercorner with one La(6)Se8 hexagonal bipyramid,  a cornercorner with one La(7)Se8 hexagonal bipyramid, corners with two equivalent La(2)Se8 hexagonal bipyramids, corners with two equivalent La(8)Se8 hexagonal bipyramids,  an edgeedge with one La(3)Se8 hexagonal bipyramid,  an edgeedge with one La(7)Se8 hexagonal bipyramid, edges with two equivalent La(1)Se8 hexagonal bipyramids,  a faceface with one La(2)Se8 hexagonal bipyramid,  a faceface with one La(3)Se8 hexagonal bipyramid,  a faceface with one La(4)Se8 hexagonal bipyramid,  a faceface with one La(6)Se8 hexagonal bipyramid,  a faceface with one La(7)Se8 hexagonal bipyramid,  a faceface with one La(8)Se8 hexagonal bipyramid, and faces with two equivalent La(5)Se8 hexagonal bipyramids. There are eight inequivalent La sites. In the first La site, La(1) is bonded to one Se(1), one Se(10), one Se(11), one Se(12), one Se(3), one Se(5), one Se(6), and one Se(9) atom to form distorted LaSe8 hexagonal bipyramids that share  a cornercorner with one La(3)Se8 hexagonal bipyramid,  a cornercorner with one La(4)Se8 hexagonal bipyramid,  a cornercorner with one La(6)Se8 hexagonal bipyramid,  a cornercorner with one La(7)Se8 hexagonal bipyramid, corners with two equivalent La(2)Se8 hexagonal bipyramids, corners with two equivalent La(8)Se8 hexagonal bipyramids,  an edgeedge with one La(4)Se8 hexagonal bipyramid,  an edgeedge with one La(6)Se8 hexagonal bipyramid, edges with two equivalent Sr(1)Se8 hexagonal bipyramids,  a faceface with one La(2)Se8 hexagonal bipyramid,  a faceface with one La(3)Se8 hexagonal bipyramid,  a faceface with one La(4)Se8 hexagonal bipyramid,  a faceface with one La(6)Se8 hexagonal bipyramid,  a faceface with one La(7)Se8 hexagonal bipyramid,  a faceface with one La(8)Se8 hexagonal bipyramid, and faces with two equivalent La(5)Se8 hexagonal bipyramids. In the second La site, La(2) is bonded to one Se(1), one Se(11), one Se(2), one Se(3), one Se(4), one Se(5), one Se(6), and one Se(8) atom to form distorted LaSe8 hexagonal bipyramids that share corners with two equivalent Sr(1)Se8 hexagonal bipyramids, corners with two equivalent La(1)Se8 hexagonal bipyramids, corners with two equivalent La(3)Se8 hexagonal bipyramids, corners with two equivalent La(6)Se8 hexagonal bipyramids, edges with two equivalent La(5)Se8 hexagonal bipyramids, edges with two equivalent La(8)Se8 hexagonal bipyramids,  a faceface with one Sr(1)Se8 hexagonal bipyramid,  a faceface with one La(1)Se8 hexagonal bipyramid,  a faceface with one La(3)Se8 hexagonal bipyramid,  a faceface with one La(6)Se8 hexagonal bipyramid, faces with two equivalent La(4)Se8 hexagonal bipyramids, and faces with two equivalent La(7)Se8 hexagonal bipyramids. In the third La site, La(3) is bonded to one Se(10), one Se(2), one Se(3), one Se(4), one Se(6), one Se(7), one Se(8), and one Se(9) atom to form distorted LaSe8 hexagonal bipyramids that share  a cornercorner with one Sr(1)Se8 hexagonal bipyramid,  a cornercorner with one La(1)Se8 hexagonal bipyramid,  a cornercorner with one La(4)Se8 hexagonal bipyramid,  a cornercorner with one La(7)Se8 hexagonal bipyramid, corners with two equivalent La(2)Se8 hexagonal bipyramids, corners with two equivalent La(5)Se8 hexagonal bipyramids,  an edgeedge with one Sr(1)Se8 hexagonal bipyramid,  an edgeedge with one La(4)Se8 hexagonal bipyramid, edges with two equivalent La(6)Se8 hexagonal bipyramids,  a faceface with one Sr(1)Se8 hexagonal bipyramid,  a faceface with one La(1)Se8 hexagonal bipyramid,  a faceface with one La(2)Se8 hexagonal bipyramid,  a faceface with one La(4)Se8 hexagonal bipyramid,  a faceface with one La(5)Se8 hexagonal bipyramid,  a faceface with one La(7)Se8 hexagonal bipyramid, and faces with two equivalent La(8)Se8 hexagonal bipyramids. In the fourth La site, La(4) is bonded to one Se(10), one Se(11), one Se(3), one Se(4), one Se(5), one Se(6), one Se(8), and one Se(9) atom to form distorted LaSe8 hexagonal bipyramids that share  a cornercorner with one Sr(1)Se8 hexagonal bipyramid,  a cornercorner with one La(1)Se8 hexagonal bipyramid,  a cornercorner with one La(3)Se8 hexagonal bipyramid,  a cornercorner with one La(6)Se8 hexagonal bipyramid, corners with two equivalent La(5)Se8 hexagonal bipyramids, corners with two equivalent La(8)Se8 hexagonal bipyramids,  an edgeedge with one La(1)Se8 hexagonal bipyramid,  an edgeedge with one La(3)Se8 hexagonal bipyramid, edges with two equivalent La(7)Se8 hexagonal bipyramids,  a faceface with one Sr(1)Se8 hexagonal bipyramid,  a faceface with one La(1)Se8 hexagonal bipyramid,  a faceface with one La(3)Se8 hexagonal bipyramid,  a faceface with one La(5)Se8 hexagonal bipyramid,  a faceface with one La(6)Se8 hexagonal bipyramid,  a faceface with one La(8)Se8 hexagonal bipyramid, and faces with two equivalent La(2)Se8 hexagonal bipyramids. In the fifth La site, La(5) is bonded to one Se(1), one Se(10), one Se(12), one Se(3), one Se(4), one Se(5), one Se(7), and one Se(9) atom to form distorted LaSe8 hexagonal bipyramids that share corners with two equivalent La(3)Se8 hexagonal bipyramids, corners with two equivalent La(4)Se8 hexagonal bipyramids, corners with two equivalent La(6)Se8 hexagonal bipyramids, corners with two equivalent La(7)Se8 hexagonal bipyramids, edges with two equivalent La(2)Se8 hexagonal bipyramids, edges with two equivalent La(8)Se8 hexagonal bipyramids,  a faceface with one La(3)Se8 hexagonal bipyramid,  a faceface with one La(4)Se8 hexagonal bipyramid,  a faceface with one La(6)Se8 hexagonal bipyramid,  a faceface with one La(7)Se8 hexagonal bipyramid, faces with two equivalent Sr(1)Se8 hexagonal bipyramids, and faces with two equivalent La(1)Se8 hexagonal bipyramids. In the sixth La site, La(6) is bonded to one Se(1), one Se(11), one Se(12), one Se(2), one Se(5), one Se(6), one Se(7), and one Se(9) atom to form distorted LaSe8 hexagonal bipyramids that share  a cornercorner with one Sr(1)Se8 hexagonal bipyramid,  a cornercorner with one La(1)Se8 hexagonal bipyramid,  a cornercorner with one La(4)Se8 hexagonal bipyramid,  a cornercorner with one La(7)Se8 hexagonal bipyramid, corners with two equivalent La(2)Se8 hexagonal bipyramids, corners with two equivalent La(5)Se8 hexagonal bipyramids,  an edgeedge with one La(1)Se8 hexagonal bipyramid,  an edgeedge with one La(7)Se8 hexagonal bipyramid, edges with two equivalent La(3)Se8 hexagonal bipyramids,  a faceface with one Sr(1)Se8 hexagonal bipyramid,  a faceface with one La(1)Se8 hexagonal bipyramid,  a faceface with one La(2)Se8 hexagonal bipyramid,  a faceface with one La(4)Se8 hexagonal bipyramid,  a faceface with one La(5)Se8 hexagonal bipyramid,  a faceface with one La(7)Se8 hexagonal bipyramid, and faces with two equivalent La(8)Se8 hexagonal bipyramids. In the seventh La site, La(7) is bonded to one Se(1), one Se(11), one Se(12), one Se(2), one Se(4), one Se(5), one Se(7), and one Se(8) atom to form distorted LaSe8 hexagonal bipyramids that share  a cornercorner with one Sr(1)Se8 hexagonal bipyramid,  a cornercorner with one La(1)Se8 hexagonal bipyramid,  a cornercorner with one La(3)Se8 hexagonal bipyramid,  a cornercorner with one La(6)Se8 hexagonal bipyramid, corners with two equivalent La(5)Se8 hexagonal bipyramids, corners with two equivalent La(8)Se8 hexagonal bipyramids,  an edgeedge with one Sr(1)Se8 hexagonal bipyramid,  an edgeedge with one La(6)Se8 hexagonal bipyramid, edges with two equivalent La(4)Se8 hexagonal bipyramids,  a faceface with one Sr(1)Se8 hexagonal bipyramid,  a faceface with one La(1)Se8 hexagonal bipyramid,  a faceface with one La(3)Se8 hexagonal bipyramid,  a faceface with one La(5)Se8 hexagonal bipyramid,  a faceface with one La(6)Se8 hexagonal bipyramid,  a faceface with one La(8)Se8 hexagonal bipyramid, and faces with two equivalent La(2)Se8 hexagonal bipyramids. In the eighth La site, La(8) is bonded to one Se(10), one Se(11), one Se(12), one Se(2), one Se(6), one Se(7), one Se(8), and one Se(9) atom to form distorted LaSe8 hexagonal bipyramids that share corners with two equivalent Sr(1)Se8 hexagonal bipyramids, corners with two equivalent La(1)Se8 hexagonal bipyramids, corners with two equivalent La(4)Se8 hexagonal bipyramids, corners with two equivalent La(7)Se8 hexagonal bipyramids, edges with two equivalent La(2)Se8 hexagonal bipyramids, edges with two equivalent La(5)Se8 hexagonal bipyramids,  a faceface with one Sr(1)Se8 hexagonal bipyramid,  a faceface with one La(1)Se8 hexagonal bipyramid,  a faceface with one La(4)Se8 hexagonal bipyramid,  a faceface with one La(7)Se8 hexagonal bipyramid, faces with two equivalent La(3)Se8 hexagonal bipyramids, and faces with two equivalent La(6)Se8 hexagonal bipyramids. There are twelve inequivalent Se sites. In the first Se site, Se(1) is bonded to one Sr(1), one La(1), one La(2), one La(5), one La(6), and one La(7) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(11)La6 octahedra,  a cornercorner with one Se(6)La6 octahedra,  a cornercorner with one Se(9)La6 octahedra,  a cornercorner with one Se(3)SrLa5 octahedra,  a cornercorner with one Se(7)SrLa5 octahedra,  a cornercorner with one Se(8)SrLa5 octahedra, corners with two equivalent Se(12)SrLa5 octahedra, corners with two equivalent Se(2)SrLa5 octahedra, corners with two equivalent Se(4)SrLa5 octahedra, corners with three equivalent Se(10)SrLa5 octahedra,  an edgeedge with one Se(5)La6 octahedra,  an edgeedge with one Se(6)La6 octahedra,  an edgeedge with one Se(9)La6 octahedra,  an edgeedge with one Se(2)SrLa5 octahedra,  an edgeedge with one Se(4)SrLa5 octahedra,  an edgeedge with one Se(8)SrLa5 octahedra,  a faceface with one Se(11)La6 octahedra,  a faceface with one Se(5)La6 octahedra,  a faceface with one Se(12)SrLa5 octahedra,  a faceface with one Se(3)SrLa5 octahedra, and  a faceface with one Se(7)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the second Se site, Se(2) is bonded to one Sr(1), one La(2), one La(3), one La(6), one La(7), and one La(8) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(6)La6 octahedra,  a cornercorner with one Se(3)SrLa5 octahedra, corners with two equivalent Se(11)La6 octahedra, corners with two equivalent Se(1)SrLa5 octahedra, corners with two equivalent Se(12)SrLa5 octahedra, corners with two equivalent Se(4)SrLa5 octahedra, corners with two equivalent Se(7)SrLa5 octahedra, corners with three equivalent Se(9)La6 octahedra,  an edgeedge with one Se(11)La6 octahedra,  an edgeedge with one Se(1)SrLa5 octahedra,  an edgeedge with one Se(12)SrLa5 octahedra,  an edgeedge with one Se(3)SrLa5 octahedra,  an edgeedge with one Se(4)SrLa5 octahedra,  an edgeedge with one Se(8)SrLa5 octahedra,  a faceface with one Se(5)La6 octahedra,  a faceface with one Se(6)La6 octahedra,  a faceface with one Se(10)SrLa5 octahedra,  a faceface with one Se(7)SrLa5 octahedra, and  a faceface with one Se(8)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the third Se site, Se(3) is bonded to one Sr(1), one La(1), one La(2), one La(3), one La(4), and one La(5) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(11)La6 octahedra,  a cornercorner with one Se(9)La6 octahedra,  a cornercorner with one Se(1)SrLa5 octahedra,  a cornercorner with one Se(2)SrLa5 octahedra,  a cornercorner with one Se(7)SrLa5 octahedra,  a cornercorner with one Se(8)SrLa5 octahedra, corners with two equivalent Se(5)La6 octahedra, corners with two equivalent Se(6)La6 octahedra, corners with two equivalent Se(10)SrLa5 octahedra, corners with three equivalent Se(12)SrLa5 octahedra,  an edgeedge with one Se(11)La6 octahedra,  an edgeedge with one Se(5)La6 octahedra,  an edgeedge with one Se(6)La6 octahedra,  an edgeedge with one Se(2)SrLa5 octahedra,  an edgeedge with one Se(4)SrLa5 octahedra,  an edgeedge with one Se(7)SrLa5 octahedra,  a faceface with one Se(9)La6 octahedra,  a faceface with one Se(1)SrLa5 octahedra,  a faceface with one Se(10)SrLa5 octahedra,  a faceface with one Se(4)SrLa5 octahedra, and  a faceface with one Se(8)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the fourth Se site, Se(4) is bonded to one Sr(1), one La(2), one La(3), one La(4), one La(5), and one La(7) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(5)La6 octahedra,  a cornercorner with one Se(9)La6 octahedra, corners with two equivalent Se(1)SrLa5 octahedra, corners with two equivalent Se(10)SrLa5 octahedra, corners with two equivalent Se(2)SrLa5 octahedra, corners with two equivalent Se(7)SrLa5 octahedra, corners with two equivalent Se(8)SrLa5 octahedra, corners with three equivalent Se(11)La6 octahedra,  an edgeedge with one Se(9)La6 octahedra,  an edgeedge with one Se(1)SrLa5 octahedra,  an edgeedge with one Se(10)SrLa5 octahedra,  an edgeedge with one Se(2)SrLa5 octahedra,  an edgeedge with one Se(3)SrLa5 octahedra,  an edgeedge with one Se(7)SrLa5 octahedra,  a faceface with one Se(5)La6 octahedra,  a faceface with one Se(6)La6 octahedra,  a faceface with one Se(12)SrLa5 octahedra,  a faceface with one Se(3)SrLa5 octahedra, and  a faceface with one Se(8)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-51°. In the fifth Se site, Se(5) is bonded to one La(1), one La(2), one La(4), one La(5), one La(6), and one La(7) atom to form distorted SeLa6 octahedra that share  a cornercorner with one Se(4)SrLa5 octahedra,  a cornercorner with one Se(7)SrLa5 octahedra, corners with two equivalent Se(11)La6 octahedra, corners with two equivalent Se(6)La6 octahedra, corners with two equivalent Se(9)La6 octahedra, corners with two equivalent Se(12)SrLa5 octahedra, corners with two equivalent Se(3)SrLa5 octahedra, corners with three equivalent Se(8)SrLa5 octahedra,  an edgeedge with one Se(6)La6 octahedra,  an edgeedge with one Se(9)La6 octahedra,  an edgeedge with one Se(1)SrLa5 octahedra,  an edgeedge with one Se(12)SrLa5 octahedra,  an edgeedge with one Se(3)SrLa5 octahedra,  an edgeedge with one Se(7)SrLa5 octahedra,  a faceface with one Se(11)La6 octahedra,  a faceface with one Se(1)SrLa5 octahedra,  a faceface with one Se(10)SrLa5 octahedra,  a faceface with one Se(2)SrLa5 octahedra, and  a faceface with one Se(4)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the sixth Se site, Se(6) is bonded to one La(1), one La(2), one La(3), one La(4), one La(6), and one La(8) atom to form distorted SeLa6 octahedra that share  a cornercorner with one Se(1)SrLa5 octahedra,  a cornercorner with one Se(2)SrLa5 octahedra, corners with two equivalent Se(5)La6 octahedra, corners with two equivalent Se(9)La6 octahedra, corners with two equivalent Se(10)SrLa5 octahedra, corners with two equivalent Se(3)SrLa5 octahedra, corners with two equivalent Se(8)SrLa5 octahedra, corners with three equivalent Se(7)SrLa5 octahedra,  an edgeedge with one Se(11)La6 octahedra,  an edgeedge with one Se(5)La6 octahedra,  an edgeedge with one Se(1)SrLa5 octahedra,  an edgeedge with one Se(10)SrLa5 octahedra,  an edgeedge with one Se(3)SrLa5 octahedra,  an edgeedge with one Se(8)SrLa5 octahedra,  a faceface with one Se(11)La6 octahedra,  a faceface with one Se(9)La6 octahedra,  a faceface with one Se(12)SrLa5 octahedra,  a faceface with one Se(2)SrLa5 octahedra, and  a faceface with one Se(4)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the seventh Se site, Se(7) is bonded to one Sr(1), one La(3), one La(5), one La(6), one La(7), and one La(8) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(11)La6 octahedra,  a cornercorner with one Se(5)La6 octahedra,  a cornercorner with one Se(9)La6 octahedra,  a cornercorner with one Se(1)SrLa5 octahedra,  a cornercorner with one Se(3)SrLa5 octahedra,  a cornercorner with one Se(8)SrLa5 octahedra, corners with two equivalent Se(10)SrLa5 octahedra, corners with two equivalent Se(2)SrLa5 octahedra, corners with two equivalent Se(4)SrLa5 octahedra, corners with three equivalent Se(6)La6 octahedra,  an edgeedge with one Se(11)La6 octahedra,  an edgeedge with one Se(5)La6 octahedra,  an edgeedge with one Se(10)SrLa5 octahedra,  an edgeedge with one Se(12)SrLa5 octahedra,  an edgeedge with one Se(3)SrLa5 octahedra,  an edgeedge with one Se(4)SrLa5 octahedra,  a faceface with one Se(9)La6 octahedra,  a faceface with one Se(1)SrLa5 octahedra,  a faceface with one Se(12)SrLa5 octahedra,  a faceface with one Se(2)SrLa5 octahedra, and  a faceface with one Se(8)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the eighth Se site, Se(8) is bonded to one Sr(1), one La(2), one La(3), one La(4), one La(7), and one La(8) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(11)La6 octahedra,  a cornercorner with one Se(9)La6 octahedra,  a cornercorner with one Se(1)SrLa5 octahedra,  a cornercorner with one Se(12)SrLa5 octahedra,  a cornercorner with one Se(3)SrLa5 octahedra,  a cornercorner with one Se(7)SrLa5 octahedra, corners with two equivalent Se(6)La6 octahedra, corners with two equivalent Se(10)SrLa5 octahedra, corners with two equivalent Se(4)SrLa5 octahedra, corners with three equivalent Se(5)La6 octahedra,  an edgeedge with one Se(6)La6 octahedra,  an edgeedge with one Se(9)La6 octahedra,  an edgeedge with one Se(1)SrLa5 octahedra,  an edgeedge with one Se(10)SrLa5 octahedra,  an edgeedge with one Se(12)SrLa5 octahedra,  an edgeedge with one Se(2)SrLa5 octahedra,  a faceface with one Se(11)La6 octahedra,  a faceface with one Se(2)SrLa5 octahedra,  a faceface with one Se(3)SrLa5 octahedra,  a faceface with one Se(4)SrLa5 octahedra, and  a faceface with one Se(7)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the ninth Se site, Se(9) is bonded to one La(1), one La(3), one La(4), one La(5), one La(6), and one La(8) atom to form distorted SeLa6 octahedra that share  a cornercorner with one Se(11)La6 octahedra,  a cornercorner with one Se(1)SrLa5 octahedra,  a cornercorner with one Se(3)SrLa5 octahedra,  a cornercorner with one Se(4)SrLa5 octahedra,  a cornercorner with one Se(7)SrLa5 octahedra,  a cornercorner with one Se(8)SrLa5 octahedra, corners with two equivalent Se(5)La6 octahedra, corners with two equivalent Se(6)La6 octahedra, corners with two equivalent Se(12)SrLa5 octahedra, corners with three equivalent Se(2)SrLa5 octahedra,  an edgeedge with one Se(5)La6 octahedra,  an edgeedge with one Se(1)SrLa5 octahedra,  an edgeedge with one Se(10)SrLa5 octahedra,  an edgeedge with one Se(12)SrLa5 octahedra,  an edgeedge with one Se(4)SrLa5 octahedra,  an edgeedge with one Se(8)SrLa5 octahedra,  a faceface with one Se(11)La6 octahedra,  a faceface with one Se(6)La6 octahedra,  a faceface with one Se(10)SrLa5 octahedra,  a faceface with one Se(3)SrLa5 octahedra, and  a faceface with one Se(7)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the tenth Se site, Se(10) is bonded to one Sr(1), one La(1), one La(3), one La(4), one La(5), and one La(8) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(11)La6 octahedra,  a cornercorner with one Se(12)SrLa5 octahedra, corners with two equivalent Se(6)La6 octahedra, corners with two equivalent Se(3)SrLa5 octahedra, corners with two equivalent Se(4)SrLa5 octahedra, corners with two equivalent Se(7)SrLa5 octahedra, corners with two equivalent Se(8)SrLa5 octahedra, corners with three equivalent Se(1)SrLa5 octahedra,  an edgeedge with one Se(11)La6 octahedra,  an edgeedge with one Se(6)La6 octahedra,  an edgeedge with one Se(9)La6 octahedra,  an edgeedge with one Se(4)SrLa5 octahedra,  an edgeedge with one Se(7)SrLa5 octahedra,  an edgeedge with one Se(8)SrLa5 octahedra,  a faceface with one Se(5)La6 octahedra,  a faceface with one Se(9)La6 octahedra,  a faceface with one Se(12)SrLa5 octahedra,  a faceface with one Se(2)SrLa5 octahedra, and  a faceface with one Se(3)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-51°. In the eleventh Se site, Se(11) is bonded to one La(1), one La(2), one La(4), one La(6), one La(7), and one La(8) atom to form distorted SeLa6 octahedra that share  a cornercorner with one Se(9)La6 octahedra,  a cornercorner with one Se(1)SrLa5 octahedra,  a cornercorner with one Se(10)SrLa5 octahedra,  a cornercorner with one Se(3)SrLa5 octahedra,  a cornercorner with one Se(7)SrLa5 octahedra,  a cornercorner with one Se(8)SrLa5 octahedra, corners with two equivalent Se(5)La6 octahedra, corners with two equivalent Se(12)SrLa5 octahedra, corners with two equivalent Se(2)SrLa5 octahedra, corners with three equivalent Se(4)SrLa5 octahedra,  an edgeedge with one Se(6)La6 octahedra,  an edgeedge with one Se(10)SrLa5 octahedra,  an edgeedge with one Se(12)SrLa5 octahedra,  an edgeedge with one Se(2)SrLa5 octahedra,  an edgeedge with one Se(3)SrLa5 octahedra,  an edgeedge with one Se(7)SrLa5 octahedra,  a faceface with one Se(5)La6 octahedra,  a faceface with one Se(6)La6 octahedra,  a faceface with one Se(9)La6 octahedra,  a faceface with one Se(1)SrLa5 octahedra, and  a faceface with one Se(8)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the twelfth Se site, Se(12) is bonded to one Sr(1), one La(1), one La(5), one La(6), one La(7), and one La(8) atom to form distorted SeSrLa5 octahedra that share  a cornercorner with one Se(10)SrLa5 octahedra,  a cornercorner with one Se(8)SrLa5 octahedra, corners with two equivalent Se(11)La6 octahedra, corners with two equivalent Se(5)La6 octahedra, corners with two equivalent Se(9)La6 octahedra, corners with two equivalent Se(1)SrLa5 octahedra, corners with two equivalent Se(2)SrLa5 octahedra, corners with three equivalent Se(3)SrLa5 octahedra,  an edgeedge with one Se(11)La6 octahedra,  an edgeedge with one Se(5)La6 octahedra,  an edgeedge with one Se(9)La6 octahedra,  an edgeedge with one Se(2)SrLa5 octahedra,  an edgeedge with one Se(7)SrLa5 octahedra,  an edgeedge with one Se(8)SrLa5 octahedra,  a faceface with one Se(6)La6 octahedra,  a faceface with one Se(1)SrLa5 octahedra,  a faceface with one Se(10)SrLa5 octahedra,  a faceface with one Se(4)SrLa5 octahedra, and  a faceface with one Se(7)SrLa5 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. is represented by the CIF card [CIF]
data_Sr(La2Se3)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.125
_cell_length_b   9.125
_cell_length_c   15.142
_cell_angle_alpha   72.476
_cell_angle_beta   72.476
_cell_angle_gamma   90.023
_symmetry_Int_Tables_number   1
_cell_volume   1140.667
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Sr  Sr0  1  0.125  0.750  0.500  1.0
  Sr  Sr1  1  0.750  0.125  1.000  1.0
  La  La2  1  0.250  0.373  1.000  1.0
  La  La3  1  0.458  0.710  0.083  1.0
  La  La4  1  0.042  0.917  0.167  1.0
  La  La5  1  0.083  0.458  0.334  1.0
  La  La6  1  0.375  0.125  0.250  1.0
  La  La7  1  0.792  0.415  0.166  1.0
  La  La8  1  0.582  0.709  0.333  1.0
  La  La9  1  0.793  0.041  0.416  1.0
  La  La10  1  0.373  0.250  0.500  1.0
  La  La11  1  0.415  0.792  0.666  1.0
  La  La12  1  0.710  0.458  0.583  1.0
  La  La13  1  0.917  0.042  0.667  1.0
  La  La14  1  0.125  0.375  0.750  1.0
  La  La15  1  0.709  0.582  0.833  1.0
  La  La16  1  0.041  0.793  0.916  1.0
  La  La17  1  0.458  0.083  0.834  1.0
  Se  Se18  1  0.547  0.403  0.051  1.0
  Se  Se19  1  0.767  0.762  0.118  1.0
  Se  Se20  1  0.396  0.049  0.050  1.0
  Se  Se21  1  0.285  0.784  0.280  1.0
  Se  Se22  1  0.434  0.433  0.284  1.0
  Se  Se23  1  0.118  0.617  0.116  1.0
  Se  Se24  1  0.716  0.066  0.219  1.0
  Se  Se25  1  0.880  0.733  0.382  1.0
  Se  Se26  1  0.066  0.217  0.217  1.0
  Se  Se27  1  0.100  0.104  0.449  1.0
  Se  Se28  1  0.733  0.383  0.383  1.0
  Se  Se29  1  0.617  0.118  0.616  1.0
  Se  Se30  1  0.762  0.767  0.618  1.0
  Se  Se31  1  0.454  0.952  0.450  1.0
  Se  Se32  1  0.049  0.396  0.550  1.0
  Se  Se33  1  0.217  0.066  0.717  1.0
  Se  Se34  1  0.403  0.547  0.551  1.0
  Se  Se35  1  0.433  0.434  0.784  1.0
  Se  Se36  1  0.066  0.716  0.719  1.0
  Se  Se37  1  0.952  0.454  0.950  1.0
  Se  Se38  1  0.104  0.100  0.949  1.0
  Se  Se39  1  0.383  0.733  0.883  1.0
  Se  Se40  1  0.784  0.285  0.780  1.0
  Se  Se41  1  0.733  0.880  0.882  1.0
[/CIF]
.