Ca(Nd2Se3)4 crystallizes in the monoclinic Cc space group. Ca(1) 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 CaSe8 hexagonal bipyramids that share  a cornercorner with one Nd(2)Se8 hexagonal bipyramid,  a cornercorner with one Nd(4)Se8 hexagonal bipyramid,  a cornercorner with one Nd(7)Se8 hexagonal bipyramid,  a cornercorner with one Nd(8)Se8 hexagonal bipyramid, corners with two equivalent Nd(1)Se8 hexagonal bipyramids, corners with two equivalent Nd(3)Se8 hexagonal bipyramids,  an edgeedge with one Nd(2)Se8 hexagonal bipyramid,  an edgeedge with one Nd(8)Se8 hexagonal bipyramid, edges with two equivalent Nd(5)Se8 hexagonal bipyramids,  a faceface with one Nd(1)Se8 hexagonal bipyramid,  a faceface with one Nd(2)Se8 hexagonal bipyramid,  a faceface with one Nd(3)Se8 hexagonal bipyramid,  a faceface with one Nd(4)Se8 hexagonal bipyramid,  a faceface with one Nd(7)Se8 hexagonal bipyramid,  a faceface with one Nd(8)Se8 hexagonal bipyramid, and faces with two equivalent Nd(6)Se8 hexagonal bipyramids. There are eight inequivalent Nd sites. In the first Nd site, Nd(1) is bonded to one Se(1), one Se(11), one Se(2), one Se(3), one Se(4), one Se(5), one Se(7), and one Se(8) atom to form distorted NdSe8 hexagonal bipyramids that share corners with two equivalent Ca(1)Se8 hexagonal bipyramids, corners with two equivalent Nd(5)Se8 hexagonal bipyramids, corners with two equivalent Nd(7)Se8 hexagonal bipyramids, corners with two equivalent Nd(8)Se8 hexagonal bipyramids, edges with two equivalent Nd(3)Se8 hexagonal bipyramids, edges with two equivalent Nd(6)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Nd(5)Se8 hexagonal bipyramid,  a faceface with one Nd(7)Se8 hexagonal bipyramid,  a faceface with one Nd(8)Se8 hexagonal bipyramid, faces with two equivalent Nd(2)Se8 hexagonal bipyramids, and faces with two equivalent Nd(4)Se8 hexagonal bipyramids. In the second Nd site, Nd(2) is bonded to one Se(10), one Se(11), one Se(3), one Se(4), one Se(5), one Se(7), one Se(8), and one Se(9) atom to form distorted NdSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Nd(5)Se8 hexagonal bipyramid,  a cornercorner with one Nd(7)Se8 hexagonal bipyramid,  a cornercorner with one Nd(8)Se8 hexagonal bipyramid, corners with two equivalent Nd(3)Se8 hexagonal bipyramids, corners with two equivalent Nd(6)Se8 hexagonal bipyramids,  an edgeedge with one Ca(1)Se8 hexagonal bipyramid,  an edgeedge with one Nd(7)Se8 hexagonal bipyramid, edges with two equivalent Nd(4)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Nd(3)Se8 hexagonal bipyramid,  a faceface with one Nd(5)Se8 hexagonal bipyramid,  a faceface with one Nd(6)Se8 hexagonal bipyramid,  a faceface with one Nd(7)Se8 hexagonal bipyramid,  a faceface with one Nd(8)Se8 hexagonal bipyramid, and faces with two equivalent Nd(1)Se8 hexagonal bipyramids. In the third Nd site, Nd(3) is bonded to one Se(1), one Se(10), one Se(12), one Se(3), one Se(4), one Se(5), one Se(6), and one Se(9) atom to form distorted NdSe8 hexagonal bipyramids that share corners with two equivalent Ca(1)Se8 hexagonal bipyramids, corners with two equivalent Nd(2)Se8 hexagonal bipyramids, corners with two equivalent Nd(4)Se8 hexagonal bipyramids, corners with two equivalent Nd(5)Se8 hexagonal bipyramids, edges with two equivalent Nd(1)Se8 hexagonal bipyramids, edges with two equivalent Nd(6)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Nd(2)Se8 hexagonal bipyramid,  a faceface with one Nd(4)Se8 hexagonal bipyramid,  a faceface with one Nd(5)Se8 hexagonal bipyramid, faces with two equivalent Nd(7)Se8 hexagonal bipyramids, and faces with two equivalent Nd(8)Se8 hexagonal bipyramids. In the fourth Nd site, Nd(4) is bonded to one Se(1), one Se(11), one Se(12), one Se(2), one Se(4), one Se(5), one Se(6), and one Se(8) atom to form distorted NdSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Nd(5)Se8 hexagonal bipyramid,  a cornercorner with one Nd(7)Se8 hexagonal bipyramid,  a cornercorner with one Nd(8)Se8 hexagonal bipyramid, corners with two equivalent Nd(3)Se8 hexagonal bipyramids, corners with two equivalent Nd(6)Se8 hexagonal bipyramids,  an edgeedge with one Nd(5)Se8 hexagonal bipyramid,  an edgeedge with one Nd(8)Se8 hexagonal bipyramid, edges with two equivalent Nd(2)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Nd(3)Se8 hexagonal bipyramid,  a faceface with one Nd(5)Se8 hexagonal bipyramid,  a faceface with one Nd(6)Se8 hexagonal bipyramid,  a faceface with one Nd(7)Se8 hexagonal bipyramid,  a faceface with one Nd(8)Se8 hexagonal bipyramid, and faces with two equivalent Nd(1)Se8 hexagonal bipyramids. In the fifth Nd site, Nd(5) 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 NdSe8 hexagonal bipyramids that share  a cornercorner with one Nd(2)Se8 hexagonal bipyramid,  a cornercorner with one Nd(4)Se8 hexagonal bipyramid,  a cornercorner with one Nd(7)Se8 hexagonal bipyramid,  a cornercorner with one Nd(8)Se8 hexagonal bipyramid, corners with two equivalent Nd(1)Se8 hexagonal bipyramids, corners with two equivalent Nd(3)Se8 hexagonal bipyramids,  an edgeedge with one Nd(4)Se8 hexagonal bipyramid,  an edgeedge with one Nd(7)Se8 hexagonal bipyramid, edges with two equivalent Ca(1)Se8 hexagonal bipyramids,  a faceface with one Nd(1)Se8 hexagonal bipyramid,  a faceface with one Nd(2)Se8 hexagonal bipyramid,  a faceface with one Nd(3)Se8 hexagonal bipyramid,  a faceface with one Nd(4)Se8 hexagonal bipyramid,  a faceface with one Nd(7)Se8 hexagonal bipyramid,  a faceface with one Nd(8)Se8 hexagonal bipyramid, and faces with two equivalent Nd(6)Se8 hexagonal bipyramids. In the sixth Nd site, Nd(6) 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 NdSe8 hexagonal bipyramids that share corners with two equivalent Nd(2)Se8 hexagonal bipyramids, corners with two equivalent Nd(4)Se8 hexagonal bipyramids, corners with two equivalent Nd(7)Se8 hexagonal bipyramids, corners with two equivalent Nd(8)Se8 hexagonal bipyramids, edges with two equivalent Nd(1)Se8 hexagonal bipyramids, edges with two equivalent Nd(3)Se8 hexagonal bipyramids,  a faceface with one Nd(2)Se8 hexagonal bipyramid,  a faceface with one Nd(4)Se8 hexagonal bipyramid,  a faceface with one Nd(7)Se8 hexagonal bipyramid,  a faceface with one Nd(8)Se8 hexagonal bipyramid, faces with two equivalent Ca(1)Se8 hexagonal bipyramids, and faces with two equivalent Nd(5)Se8 hexagonal bipyramids. In the seventh Nd site, Nd(7) is bonded to one Se(1), one Se(10), one Se(11), one Se(12), one Se(3), one Se(5), one Se(7), and one Se(9) atom to form distorted NdSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Nd(2)Se8 hexagonal bipyramid,  a cornercorner with one Nd(4)Se8 hexagonal bipyramid,  a cornercorner with one Nd(5)Se8 hexagonal bipyramid, corners with two equivalent Nd(1)Se8 hexagonal bipyramids, corners with two equivalent Nd(6)Se8 hexagonal bipyramids,  an edgeedge with one Nd(2)Se8 hexagonal bipyramid,  an edgeedge with one Nd(5)Se8 hexagonal bipyramid, edges with two equivalent Nd(8)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Nd(1)Se8 hexagonal bipyramid,  a faceface with one Nd(2)Se8 hexagonal bipyramid,  a faceface with one Nd(4)Se8 hexagonal bipyramid,  a faceface with one Nd(5)Se8 hexagonal bipyramid,  a faceface with one Nd(6)Se8 hexagonal bipyramid, and faces with two equivalent Nd(3)Se8 hexagonal bipyramids. In the eighth Nd site, Nd(8) is bonded to one Se(1), one Se(10), one Se(12), one Se(2), one Se(3), one Se(4), one Se(6), and one Se(8) atom to form distorted NdSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Nd(2)Se8 hexagonal bipyramid,  a cornercorner with one Nd(4)Se8 hexagonal bipyramid,  a cornercorner with one Nd(5)Se8 hexagonal bipyramid, corners with two equivalent Nd(1)Se8 hexagonal bipyramids, corners with two equivalent Nd(6)Se8 hexagonal bipyramids,  an edgeedge with one Ca(1)Se8 hexagonal bipyramid,  an edgeedge with one Nd(4)Se8 hexagonal bipyramid, edges with two equivalent Nd(7)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Nd(1)Se8 hexagonal bipyramid,  a faceface with one Nd(2)Se8 hexagonal bipyramid,  a faceface with one Nd(4)Se8 hexagonal bipyramid,  a faceface with one Nd(5)Se8 hexagonal bipyramid,  a faceface with one Nd(6)Se8 hexagonal bipyramid, and faces with two equivalent Nd(3)Se8 hexagonal bipyramids. There are twelve inequivalent Se sites. In the first Se site, Se(1) is bonded to one Nd(1), one Nd(3), one Nd(4), one Nd(5), one Nd(7), and one Nd(8) atom to form distorted SeNd6 octahedra that share  a cornercorner with one Se(3)CaNd5 octahedra,  a cornercorner with one Se(6)CaNd5 octahedra,  a cornercorner with one Se(7)CaNd5 octahedra,  a cornercorner with one Se(8)CaNd5 octahedra,  a cornercorner with one Se(9)CaNd5 octahedra,  a cornercorner with one Se(11)Nd6 octahedra, corners with two equivalent Se(2)CaNd5 octahedra, corners with two equivalent Se(4)CaNd5 octahedra, corners with two equivalent Se(12)Nd6 octahedra, corners with three equivalent Se(10)CaNd5 octahedra,  an edgeedge with one Se(2)CaNd5 octahedra,  an edgeedge with one Se(4)CaNd5 octahedra,  an edgeedge with one Se(7)CaNd5 octahedra,  an edgeedge with one Se(8)CaNd5 octahedra,  an edgeedge with one Se(9)CaNd5 octahedra,  an edgeedge with one Se(5)Nd6 octahedra,  a faceface with one Se(3)CaNd5 octahedra,  a faceface with one Se(6)CaNd5 octahedra,  a faceface with one Se(11)Nd6 octahedra,  a faceface with one Se(12)Nd6 octahedra, and  a faceface with one Se(5)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the second Se site, Se(2) is bonded to one Ca(1), one Nd(1), one Nd(4), one Nd(5), one Nd(6), and one Nd(8) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(3)CaNd5 octahedra,  a cornercorner with one Se(7)CaNd5 octahedra, corners with two equivalent Se(4)CaNd5 octahedra, corners with two equivalent Se(6)CaNd5 octahedra, corners with two equivalent Se(1)Nd6 octahedra, corners with two equivalent Se(11)Nd6 octahedra, corners with two equivalent Se(12)Nd6 octahedra, corners with three equivalent Se(9)CaNd5 octahedra,  an edgeedge with one Se(3)CaNd5 octahedra,  an edgeedge with one Se(4)CaNd5 octahedra,  an edgeedge with one Se(8)CaNd5 octahedra,  an edgeedge with one Se(1)Nd6 octahedra,  an edgeedge with one Se(11)Nd6 octahedra,  an edgeedge with one Se(12)Nd6 octahedra,  a faceface with one Se(10)CaNd5 octahedra,  a faceface with one Se(6)CaNd5 octahedra,  a faceface with one Se(7)CaNd5 octahedra,  a faceface with one Se(8)CaNd5 octahedra, and  a faceface with one Se(5)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 18-50°. In the third Se site, Se(3) is bonded to one Ca(1), one Nd(1), one Nd(2), one Nd(3), one Nd(7), and one Nd(8) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(2)CaNd5 octahedra,  a cornercorner with one Se(6)CaNd5 octahedra,  a cornercorner with one Se(8)CaNd5 octahedra,  a cornercorner with one Se(9)CaNd5 octahedra,  a cornercorner with one Se(1)Nd6 octahedra,  a cornercorner with one Se(11)Nd6 octahedra, corners with two equivalent Se(10)CaNd5 octahedra, corners with two equivalent Se(7)CaNd5 octahedra, corners with two equivalent Se(5)Nd6 octahedra, corners with three equivalent Se(12)Nd6 octahedra,  an edgeedge with one Se(2)CaNd5 octahedra,  an edgeedge with one Se(4)CaNd5 octahedra,  an edgeedge with one Se(6)CaNd5 octahedra,  an edgeedge with one Se(7)CaNd5 octahedra,  an edgeedge with one Se(11)Nd6 octahedra,  an edgeedge with one Se(5)Nd6 octahedra,  a faceface with one Se(10)CaNd5 octahedra,  a faceface with one Se(4)CaNd5 octahedra,  a faceface with one Se(8)CaNd5 octahedra,  a faceface with one Se(9)CaNd5 octahedra, and  a faceface with one Se(1)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the fourth Se site, Se(4) is bonded to one Ca(1), one Nd(1), one Nd(2), one Nd(3), one Nd(4), and one Nd(8) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(9)CaNd5 octahedra,  a cornercorner with one Se(5)Nd6 octahedra, corners with two equivalent Se(10)CaNd5 octahedra, corners with two equivalent Se(2)CaNd5 octahedra, corners with two equivalent Se(6)CaNd5 octahedra, corners with two equivalent Se(8)CaNd5 octahedra, corners with two equivalent Se(1)Nd6 octahedra, corners with three equivalent Se(11)Nd6 octahedra,  an edgeedge with one Se(10)CaNd5 octahedra,  an edgeedge with one Se(2)CaNd5 octahedra,  an edgeedge with one Se(3)CaNd5 octahedra,  an edgeedge with one Se(6)CaNd5 octahedra,  an edgeedge with one Se(9)CaNd5 octahedra,  an edgeedge with one Se(1)Nd6 octahedra,  a faceface with one Se(3)CaNd5 octahedra,  a faceface with one Se(7)CaNd5 octahedra,  a faceface with one Se(8)CaNd5 octahedra,  a faceface with one Se(12)Nd6 octahedra, and  a faceface with one Se(5)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the fifth Se site, Se(5) is bonded to one Nd(1), one Nd(2), one Nd(3), one Nd(4), one Nd(5), and one Nd(7) atom to form distorted SeNd6 octahedra that share  a cornercorner with one Se(4)CaNd5 octahedra,  a cornercorner with one Se(6)CaNd5 octahedra, corners with two equivalent Se(3)CaNd5 octahedra, corners with two equivalent Se(7)CaNd5 octahedra, corners with two equivalent Se(9)CaNd5 octahedra, corners with two equivalent Se(11)Nd6 octahedra, corners with two equivalent Se(12)Nd6 octahedra, corners with three equivalent Se(8)CaNd5 octahedra,  an edgeedge with one Se(3)CaNd5 octahedra,  an edgeedge with one Se(6)CaNd5 octahedra,  an edgeedge with one Se(7)CaNd5 octahedra,  an edgeedge with one Se(9)CaNd5 octahedra,  an edgeedge with one Se(1)Nd6 octahedra,  an edgeedge with one Se(12)Nd6 octahedra,  a faceface with one Se(10)CaNd5 octahedra,  a faceface with one Se(2)CaNd5 octahedra,  a faceface with one Se(4)CaNd5 octahedra,  a faceface with one Se(1)Nd6 octahedra, and  a faceface with one Se(11)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the sixth Se site, Se(6) is bonded to one Ca(1), one Nd(3), one Nd(4), one Nd(5), one Nd(6), and one Nd(8) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(3)CaNd5 octahedra,  a cornercorner with one Se(8)CaNd5 octahedra,  a cornercorner with one Se(9)CaNd5 octahedra,  a cornercorner with one Se(1)Nd6 octahedra,  a cornercorner with one Se(11)Nd6 octahedra,  a cornercorner with one Se(5)Nd6 octahedra, corners with two equivalent Se(10)CaNd5 octahedra, corners with two equivalent Se(2)CaNd5 octahedra, corners with two equivalent Se(4)CaNd5 octahedra, corners with three equivalent Se(7)CaNd5 octahedra,  an edgeedge with one Se(10)CaNd5 octahedra,  an edgeedge with one Se(3)CaNd5 octahedra,  an edgeedge with one Se(4)CaNd5 octahedra,  an edgeedge with one Se(11)Nd6 octahedra,  an edgeedge with one Se(12)Nd6 octahedra,  an edgeedge with one Se(5)Nd6 octahedra,  a faceface with one Se(2)CaNd5 octahedra,  a faceface with one Se(8)CaNd5 octahedra,  a faceface with one Se(9)CaNd5 octahedra,  a faceface with one Se(1)Nd6 octahedra, and  a faceface with one Se(12)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the seventh Se site, Se(7) is bonded to one Ca(1), one Nd(1), one Nd(2), one Nd(5), one Nd(6), and one Nd(7) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(2)CaNd5 octahedra,  a cornercorner with one Se(1)Nd6 octahedra, corners with two equivalent Se(10)CaNd5 octahedra, corners with two equivalent Se(3)CaNd5 octahedra, corners with two equivalent Se(8)CaNd5 octahedra, corners with two equivalent Se(9)CaNd5 octahedra, corners with two equivalent Se(5)Nd6 octahedra, corners with three equivalent Se(6)CaNd5 octahedra,  an edgeedge with one Se(10)CaNd5 octahedra,  an edgeedge with one Se(3)CaNd5 octahedra,  an edgeedge with one Se(8)CaNd5 octahedra,  an edgeedge with one Se(1)Nd6 octahedra,  an edgeedge with one Se(11)Nd6 octahedra,  an edgeedge with one Se(5)Nd6 octahedra,  a faceface with one Se(2)CaNd5 octahedra,  a faceface with one Se(4)CaNd5 octahedra,  a faceface with one Se(9)CaNd5 octahedra,  a faceface with one Se(11)Nd6 octahedra, and  a faceface with one Se(12)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the eighth Se site, Se(8) is bonded to one Ca(1), one Nd(1), one Nd(2), one Nd(4), one Nd(6), and one Nd(8) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(3)CaNd5 octahedra,  a cornercorner with one Se(6)CaNd5 octahedra,  a cornercorner with one Se(9)CaNd5 octahedra,  a cornercorner with one Se(1)Nd6 octahedra,  a cornercorner with one Se(11)Nd6 octahedra,  a cornercorner with one Se(12)Nd6 octahedra, corners with two equivalent Se(10)CaNd5 octahedra, corners with two equivalent Se(4)CaNd5 octahedra, corners with two equivalent Se(7)CaNd5 octahedra, corners with three equivalent Se(5)Nd6 octahedra,  an edgeedge with one Se(10)CaNd5 octahedra,  an edgeedge with one Se(2)CaNd5 octahedra,  an edgeedge with one Se(7)CaNd5 octahedra,  an edgeedge with one Se(9)CaNd5 octahedra,  an edgeedge with one Se(1)Nd6 octahedra,  an edgeedge with one Se(12)Nd6 octahedra,  a faceface with one Se(2)CaNd5 octahedra,  a faceface with one Se(3)CaNd5 octahedra,  a faceface with one Se(4)CaNd5 octahedra,  a faceface with one Se(6)CaNd5 octahedra, and  a faceface with one Se(11)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the ninth Se site, Se(9) is bonded to one Ca(1), one Nd(2), one Nd(3), one Nd(5), one Nd(6), and one Nd(7) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(3)CaNd5 octahedra,  a cornercorner with one Se(4)CaNd5 octahedra,  a cornercorner with one Se(6)CaNd5 octahedra,  a cornercorner with one Se(8)CaNd5 octahedra,  a cornercorner with one Se(1)Nd6 octahedra,  a cornercorner with one Se(11)Nd6 octahedra, corners with two equivalent Se(7)CaNd5 octahedra, corners with two equivalent Se(12)Nd6 octahedra, corners with two equivalent Se(5)Nd6 octahedra, corners with three equivalent Se(2)CaNd5 octahedra,  an edgeedge with one Se(10)CaNd5 octahedra,  an edgeedge with one Se(4)CaNd5 octahedra,  an edgeedge with one Se(8)CaNd5 octahedra,  an edgeedge with one Se(1)Nd6 octahedra,  an edgeedge with one Se(12)Nd6 octahedra,  an edgeedge with one Se(5)Nd6 octahedra,  a faceface with one Se(10)CaNd5 octahedra,  a faceface with one Se(3)CaNd5 octahedra,  a faceface with one Se(6)CaNd5 octahedra,  a faceface with one Se(7)CaNd5 octahedra, and  a faceface with one Se(11)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the tenth Se site, Se(10) is bonded to one Ca(1), one Nd(2), one Nd(3), one Nd(6), one Nd(7), and one Nd(8) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(11)Nd6 octahedra,  a cornercorner with one Se(12)Nd6 octahedra, corners with two equivalent Se(3)CaNd5 octahedra, corners with two equivalent Se(4)CaNd5 octahedra, corners with two equivalent Se(6)CaNd5 octahedra, corners with two equivalent Se(7)CaNd5 octahedra, corners with two equivalent Se(8)CaNd5 octahedra, corners with three equivalent Se(1)Nd6 octahedra,  an edgeedge with one Se(4)CaNd5 octahedra,  an edgeedge with one Se(6)CaNd5 octahedra,  an edgeedge with one Se(7)CaNd5 octahedra,  an edgeedge with one Se(8)CaNd5 octahedra,  an edgeedge with one Se(9)CaNd5 octahedra,  an edgeedge with one Se(11)Nd6 octahedra,  a faceface with one Se(2)CaNd5 octahedra,  a faceface with one Se(3)CaNd5 octahedra,  a faceface with one Se(9)CaNd5 octahedra,  a faceface with one Se(12)Nd6 octahedra, and  a faceface with one Se(5)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the eleventh Se site, Se(11) is bonded to one Nd(1), one Nd(2), one Nd(4), one Nd(5), one Nd(6), and one Nd(7) atom to form distorted SeNd6 octahedra that share  a cornercorner with one Se(10)CaNd5 octahedra,  a cornercorner with one Se(3)CaNd5 octahedra,  a cornercorner with one Se(6)CaNd5 octahedra,  a cornercorner with one Se(8)CaNd5 octahedra,  a cornercorner with one Se(9)CaNd5 octahedra,  a cornercorner with one Se(1)Nd6 octahedra, corners with two equivalent Se(2)CaNd5 octahedra, corners with two equivalent Se(12)Nd6 octahedra, corners with two equivalent Se(5)Nd6 octahedra, corners with three equivalent Se(4)CaNd5 octahedra,  an edgeedge with one Se(10)CaNd5 octahedra,  an edgeedge with one Se(2)CaNd5 octahedra,  an edgeedge with one Se(3)CaNd5 octahedra,  an edgeedge with one Se(6)CaNd5 octahedra,  an edgeedge with one Se(7)CaNd5 octahedra,  an edgeedge with one Se(12)Nd6 octahedra,  a faceface with one Se(7)CaNd5 octahedra,  a faceface with one Se(8)CaNd5 octahedra,  a faceface with one Se(9)CaNd5 octahedra,  a faceface with one Se(1)Nd6 octahedra, and  a faceface with one Se(5)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the twelfth Se site, Se(12) is bonded to one Nd(3), one Nd(4), one Nd(5), one Nd(6), one Nd(7), and one Nd(8) atom to form distorted SeNd6 octahedra that share  a cornercorner with one Se(10)CaNd5 octahedra,  a cornercorner with one Se(8)CaNd5 octahedra, corners with two equivalent Se(2)CaNd5 octahedra, corners with two equivalent Se(9)CaNd5 octahedra, corners with two equivalent Se(1)Nd6 octahedra, corners with two equivalent Se(11)Nd6 octahedra, corners with two equivalent Se(5)Nd6 octahedra, corners with three equivalent Se(3)CaNd5 octahedra,  an edgeedge with one Se(2)CaNd5 octahedra,  an edgeedge with one Se(6)CaNd5 octahedra,  an edgeedge with one Se(8)CaNd5 octahedra,  an edgeedge with one Se(9)CaNd5 octahedra,  an edgeedge with one Se(11)Nd6 octahedra,  an edgeedge with one Se(5)Nd6 octahedra,  a faceface with one Se(10)CaNd5 octahedra,  a faceface with one Se(4)CaNd5 octahedra,  a faceface with one Se(6)CaNd5 octahedra,  a faceface with one Se(7)CaNd5 octahedra, and  a faceface with one Se(1)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 16-50°.
Ca(Nd2Se3)4 crystallizes in the monoclinic Cc space group. Ca(1) 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 CaSe8 hexagonal bipyramids that share  a cornercorner with one Nd(2)Se8 hexagonal bipyramid,  a cornercorner with one Nd(4)Se8 hexagonal bipyramid,  a cornercorner with one Nd(7)Se8 hexagonal bipyramid,  a cornercorner with one Nd(8)Se8 hexagonal bipyramid, corners with two equivalent Nd(1)Se8 hexagonal bipyramids, corners with two equivalent Nd(3)Se8 hexagonal bipyramids,  an edgeedge with one Nd(2)Se8 hexagonal bipyramid,  an edgeedge with one Nd(8)Se8 hexagonal bipyramid, edges with two equivalent Nd(5)Se8 hexagonal bipyramids,  a faceface with one Nd(1)Se8 hexagonal bipyramid,  a faceface with one Nd(2)Se8 hexagonal bipyramid,  a faceface with one Nd(3)Se8 hexagonal bipyramid,  a faceface with one Nd(4)Se8 hexagonal bipyramid,  a faceface with one Nd(7)Se8 hexagonal bipyramid,  a faceface with one Nd(8)Se8 hexagonal bipyramid, and faces with two equivalent Nd(6)Se8 hexagonal bipyramids. The Ca(1)-Se(10) bond length is 3.01 Å. The Ca(1)-Se(2) bond length is 3.22 Å. The Ca(1)-Se(3) bond length is 3.22 Å. The Ca(1)-Se(4) bond length is 3.22 Å. The Ca(1)-Se(6) bond length is 3.23 Å. The Ca(1)-Se(7) bond length is 3.00 Å. The Ca(1)-Se(8) bond length is 3.00 Å. The Ca(1)-Se(9) bond length is 3.00 Å. There are eight inequivalent Nd sites. In the first Nd site, Nd(1) is bonded to one Se(1), one Se(11), one Se(2), one Se(3), one Se(4), one Se(5), one Se(7), and one Se(8) atom to form distorted NdSe8 hexagonal bipyramids that share corners with two equivalent Ca(1)Se8 hexagonal bipyramids, corners with two equivalent Nd(5)Se8 hexagonal bipyramids, corners with two equivalent Nd(7)Se8 hexagonal bipyramids, corners with two equivalent Nd(8)Se8 hexagonal bipyramids, edges with two equivalent Nd(3)Se8 hexagonal bipyramids, edges with two equivalent Nd(6)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Nd(5)Se8 hexagonal bipyramid,  a faceface with one Nd(7)Se8 hexagonal bipyramid,  a faceface with one Nd(8)Se8 hexagonal bipyramid, faces with two equivalent Nd(2)Se8 hexagonal bipyramids, and faces with two equivalent Nd(4)Se8 hexagonal bipyramids. The Nd(1)-Se(1) bond length is 3.02 Å. The Nd(1)-Se(11) bond length is 3.17 Å. The Nd(1)-Se(2) bond length is 2.99 Å. The Nd(1)-Se(3) bond length is 3.00 Å. The Nd(1)-Se(4) bond length is 3.19 Å. The Nd(1)-Se(5) bond length is 3.20 Å. The Nd(1)-Se(7) bond length is 3.02 Å. The Nd(1)-Se(8) bond length is 3.19 Å. In the second Nd site, Nd(2) is bonded to one Se(10), one Se(11), one Se(3), one Se(4), one Se(5), one Se(7), one Se(8), and one Se(9) atom to form distorted NdSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Nd(5)Se8 hexagonal bipyramid,  a cornercorner with one Nd(7)Se8 hexagonal bipyramid,  a cornercorner with one Nd(8)Se8 hexagonal bipyramid, corners with two equivalent Nd(3)Se8 hexagonal bipyramids, corners with two equivalent Nd(6)Se8 hexagonal bipyramids,  an edgeedge with one Ca(1)Se8 hexagonal bipyramid,  an edgeedge with one Nd(7)Se8 hexagonal bipyramid, edges with two equivalent Nd(4)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Nd(3)Se8 hexagonal bipyramid,  a faceface with one Nd(5)Se8 hexagonal bipyramid,  a faceface with one Nd(6)Se8 hexagonal bipyramid,  a faceface with one Nd(7)Se8 hexagonal bipyramid,  a faceface with one Nd(8)Se8 hexagonal bipyramid, and faces with two equivalent Nd(1)Se8 hexagonal bipyramids. The Nd(2)-Se(10) bond length is 3.15 Å. The Nd(2)-Se(11) bond length is 3.02 Å. The Nd(2)-Se(3) bond length is 3.01 Å. The Nd(2)-Se(4) bond length is 3.22 Å. The Nd(2)-Se(5) bond length is 3.01 Å. The Nd(2)-Se(7) bond length is 3.02 Å. The Nd(2)-Se(8) bond length is 3.21 Å. The Nd(2)-Se(9) bond length is 3.18 Å. In the third Nd site, Nd(3) is bonded to one Se(1), one Se(10), one Se(12), one Se(3), one Se(4), one Se(5), one Se(6), and one Se(9) atom to form distorted NdSe8 hexagonal bipyramids that share corners with two equivalent Ca(1)Se8 hexagonal bipyramids, corners with two equivalent Nd(2)Se8 hexagonal bipyramids, corners with two equivalent Nd(4)Se8 hexagonal bipyramids, corners with two equivalent Nd(5)Se8 hexagonal bipyramids, edges with two equivalent Nd(1)Se8 hexagonal bipyramids, edges with two equivalent Nd(6)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Nd(2)Se8 hexagonal bipyramid,  a faceface with one Nd(4)Se8 hexagonal bipyramid,  a faceface with one Nd(5)Se8 hexagonal bipyramid, faces with two equivalent Nd(7)Se8 hexagonal bipyramids, and faces with two equivalent Nd(8)Se8 hexagonal bipyramids. The Nd(3)-Se(1) bond length is 3.19 Å. The Nd(3)-Se(10) bond length is 3.17 Å. The Nd(3)-Se(12) bond length is 3.20 Å. The Nd(3)-Se(3) bond length is 3.19 Å. The Nd(3)-Se(4) bond length is 3.01 Å. The Nd(3)-Se(5) bond length is 3.01 Å. The Nd(3)-Se(6) bond length is 3.00 Å. The Nd(3)-Se(9) bond length is 3.01 Å. In the fourth Nd site, Nd(4) is bonded to one Se(1), one Se(11), one Se(12), one Se(2), one Se(4), one Se(5), one Se(6), and one Se(8) atom to form distorted NdSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Nd(5)Se8 hexagonal bipyramid,  a cornercorner with one Nd(7)Se8 hexagonal bipyramid,  a cornercorner with one Nd(8)Se8 hexagonal bipyramid, corners with two equivalent Nd(3)Se8 hexagonal bipyramids, corners with two equivalent Nd(6)Se8 hexagonal bipyramids,  an edgeedge with one Nd(5)Se8 hexagonal bipyramid,  an edgeedge with one Nd(8)Se8 hexagonal bipyramid, edges with two equivalent Nd(2)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Nd(3)Se8 hexagonal bipyramid,  a faceface with one Nd(5)Se8 hexagonal bipyramid,  a faceface with one Nd(6)Se8 hexagonal bipyramid,  a faceface with one Nd(7)Se8 hexagonal bipyramid,  a faceface with one Nd(8)Se8 hexagonal bipyramid, and faces with two equivalent Nd(1)Se8 hexagonal bipyramids. The Nd(4)-Se(1) bond length is 3.02 Å. The Nd(4)-Se(11) bond length is 3.18 Å. The Nd(4)-Se(12) bond length is 3.20 Å. The Nd(4)-Se(2) bond length is 2.99 Å. The Nd(4)-Se(4) bond length is 3.00 Å. The Nd(4)-Se(5) bond length is 3.20 Å. The Nd(4)-Se(6) bond length is 3.18 Å. The Nd(4)-Se(8) bond length is 3.01 Å. In the fifth Nd site, Nd(5) 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 NdSe8 hexagonal bipyramids that share  a cornercorner with one Nd(2)Se8 hexagonal bipyramid,  a cornercorner with one Nd(4)Se8 hexagonal bipyramid,  a cornercorner with one Nd(7)Se8 hexagonal bipyramid,  a cornercorner with one Nd(8)Se8 hexagonal bipyramid, corners with two equivalent Nd(1)Se8 hexagonal bipyramids, corners with two equivalent Nd(3)Se8 hexagonal bipyramids,  an edgeedge with one Nd(4)Se8 hexagonal bipyramid,  an edgeedge with one Nd(7)Se8 hexagonal bipyramid, edges with two equivalent Ca(1)Se8 hexagonal bipyramids,  a faceface with one Nd(1)Se8 hexagonal bipyramid,  a faceface with one Nd(2)Se8 hexagonal bipyramid,  a faceface with one Nd(3)Se8 hexagonal bipyramid,  a faceface with one Nd(4)Se8 hexagonal bipyramid,  a faceface with one Nd(7)Se8 hexagonal bipyramid,  a faceface with one Nd(8)Se8 hexagonal bipyramid, and faces with two equivalent Nd(6)Se8 hexagonal bipyramids. The Nd(5)-Se(1) bond length is 3.21 Å. The Nd(5)-Se(11) bond length is 3.02 Å. The Nd(5)-Se(12) bond length is 3.00 Å. The Nd(5)-Se(2) bond length is 3.01 Å. The Nd(5)-Se(5) bond length is 3.21 Å. The Nd(5)-Se(6) bond length is 3.01 Å. The Nd(5)-Se(7) bond length is 3.16 Å. The Nd(5)-Se(9) bond length is 3.16 Å. In the sixth Nd site, Nd(6) 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 NdSe8 hexagonal bipyramids that share corners with two equivalent Nd(2)Se8 hexagonal bipyramids, corners with two equivalent Nd(4)Se8 hexagonal bipyramids, corners with two equivalent Nd(7)Se8 hexagonal bipyramids, corners with two equivalent Nd(8)Se8 hexagonal bipyramids, edges with two equivalent Nd(1)Se8 hexagonal bipyramids, edges with two equivalent Nd(3)Se8 hexagonal bipyramids,  a faceface with one Nd(2)Se8 hexagonal bipyramid,  a faceface with one Nd(4)Se8 hexagonal bipyramid,  a faceface with one Nd(7)Se8 hexagonal bipyramid,  a faceface with one Nd(8)Se8 hexagonal bipyramid, faces with two equivalent Ca(1)Se8 hexagonal bipyramids, and faces with two equivalent Nd(5)Se8 hexagonal bipyramids. The Nd(6)-Se(10) bond length is 3.02 Å. The Nd(6)-Se(11) bond length is 3.02 Å. The Nd(6)-Se(12) bond length is 3.01 Å. The Nd(6)-Se(2) bond length is 3.20 Å. The Nd(6)-Se(6) bond length is 3.19 Å. The Nd(6)-Se(7) bond length is 3.18 Å. The Nd(6)-Se(8) bond length is 3.01 Å. The Nd(6)-Se(9) bond length is 3.18 Å. In the seventh Nd site, Nd(7) is bonded to one Se(1), one Se(10), one Se(11), one Se(12), one Se(3), one Se(5), one Se(7), and one Se(9) atom to form distorted NdSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Nd(2)Se8 hexagonal bipyramid,  a cornercorner with one Nd(4)Se8 hexagonal bipyramid,  a cornercorner with one Nd(5)Se8 hexagonal bipyramid, corners with two equivalent Nd(1)Se8 hexagonal bipyramids, corners with two equivalent Nd(6)Se8 hexagonal bipyramids,  an edgeedge with one Nd(2)Se8 hexagonal bipyramid,  an edgeedge with one Nd(5)Se8 hexagonal bipyramid, edges with two equivalent Nd(8)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Nd(1)Se8 hexagonal bipyramid,  a faceface with one Nd(2)Se8 hexagonal bipyramid,  a faceface with one Nd(4)Se8 hexagonal bipyramid,  a faceface with one Nd(5)Se8 hexagonal bipyramid,  a faceface with one Nd(6)Se8 hexagonal bipyramid, and faces with two equivalent Nd(3)Se8 hexagonal bipyramids. The Nd(7)-Se(1) bond length is 3.01 Å. The Nd(7)-Se(10) bond length is 3.19 Å. The Nd(7)-Se(11) bond length is 3.17 Å. The Nd(7)-Se(12) bond length is 3.02 Å. The Nd(7)-Se(3) bond length is 3.21 Å. The Nd(7)-Se(5) bond length is 3.02 Å. The Nd(7)-Se(7) bond length is 3.19 Å. The Nd(7)-Se(9) bond length is 3.00 Å. In the eighth Nd site, Nd(8) is bonded to one Se(1), one Se(10), one Se(12), one Se(2), one Se(3), one Se(4), one Se(6), and one Se(8) atom to form distorted NdSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Nd(2)Se8 hexagonal bipyramid,  a cornercorner with one Nd(4)Se8 hexagonal bipyramid,  a cornercorner with one Nd(5)Se8 hexagonal bipyramid, corners with two equivalent Nd(1)Se8 hexagonal bipyramids, corners with two equivalent Nd(6)Se8 hexagonal bipyramids,  an edgeedge with one Ca(1)Se8 hexagonal bipyramid,  an edgeedge with one Nd(4)Se8 hexagonal bipyramid, edges with two equivalent Nd(7)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Nd(1)Se8 hexagonal bipyramid,  a faceface with one Nd(2)Se8 hexagonal bipyramid,  a faceface with one Nd(4)Se8 hexagonal bipyramid,  a faceface with one Nd(5)Se8 hexagonal bipyramid,  a faceface with one Nd(6)Se8 hexagonal bipyramid, and faces with two equivalent Nd(3)Se8 hexagonal bipyramids. The Nd(8)-Se(1) bond length is 3.22 Å. The Nd(8)-Se(10) bond length is 3.01 Å. The Nd(8)-Se(12) bond length is 3.19 Å. The Nd(8)-Se(2) bond length is 3.18 Å. The Nd(8)-Se(3) bond length is 2.99 Å. The Nd(8)-Se(4) bond length is 3.00 Å. The Nd(8)-Se(6) bond length is 3.01 Å. The Nd(8)-Se(8) bond length is 3.17 Å. There are twelve inequivalent Se sites. In the first Se site, Se(1) is bonded to one Nd(1), one Nd(3), one Nd(4), one Nd(5), one Nd(7), and one Nd(8) atom to form distorted SeNd6 octahedra that share  a cornercorner with one Se(3)CaNd5 octahedra,  a cornercorner with one Se(6)CaNd5 octahedra,  a cornercorner with one Se(7)CaNd5 octahedra,  a cornercorner with one Se(8)CaNd5 octahedra,  a cornercorner with one Se(9)CaNd5 octahedra,  a cornercorner with one Se(11)Nd6 octahedra, corners with two equivalent Se(2)CaNd5 octahedra, corners with two equivalent Se(4)CaNd5 octahedra, corners with two equivalent Se(12)Nd6 octahedra, corners with three equivalent Se(10)CaNd5 octahedra,  an edgeedge with one Se(2)CaNd5 octahedra,  an edgeedge with one Se(4)CaNd5 octahedra,  an edgeedge with one Se(7)CaNd5 octahedra,  an edgeedge with one Se(8)CaNd5 octahedra,  an edgeedge with one Se(9)CaNd5 octahedra,  an edgeedge with one Se(5)Nd6 octahedra,  a faceface with one Se(3)CaNd5 octahedra,  a faceface with one Se(6)CaNd5 octahedra,  a faceface with one Se(11)Nd6 octahedra,  a faceface with one Se(12)Nd6 octahedra, and  a faceface with one Se(5)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the second Se site, Se(2) is bonded to one Ca(1), one Nd(1), one Nd(4), one Nd(5), one Nd(6), and one Nd(8) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(3)CaNd5 octahedra,  a cornercorner with one Se(7)CaNd5 octahedra, corners with two equivalent Se(4)CaNd5 octahedra, corners with two equivalent Se(6)CaNd5 octahedra, corners with two equivalent Se(1)Nd6 octahedra, corners with two equivalent Se(11)Nd6 octahedra, corners with two equivalent Se(12)Nd6 octahedra, corners with three equivalent Se(9)CaNd5 octahedra,  an edgeedge with one Se(3)CaNd5 octahedra,  an edgeedge with one Se(4)CaNd5 octahedra,  an edgeedge with one Se(8)CaNd5 octahedra,  an edgeedge with one Se(1)Nd6 octahedra,  an edgeedge with one Se(11)Nd6 octahedra,  an edgeedge with one Se(12)Nd6 octahedra,  a faceface with one Se(10)CaNd5 octahedra,  a faceface with one Se(6)CaNd5 octahedra,  a faceface with one Se(7)CaNd5 octahedra,  a faceface with one Se(8)CaNd5 octahedra, and  a faceface with one Se(5)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 18-50°. In the third Se site, Se(3) is bonded to one Ca(1), one Nd(1), one Nd(2), one Nd(3), one Nd(7), and one Nd(8) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(2)CaNd5 octahedra,  a cornercorner with one Se(6)CaNd5 octahedra,  a cornercorner with one Se(8)CaNd5 octahedra,  a cornercorner with one Se(9)CaNd5 octahedra,  a cornercorner with one Se(1)Nd6 octahedra,  a cornercorner with one Se(11)Nd6 octahedra, corners with two equivalent Se(10)CaNd5 octahedra, corners with two equivalent Se(7)CaNd5 octahedra, corners with two equivalent Se(5)Nd6 octahedra, corners with three equivalent Se(12)Nd6 octahedra,  an edgeedge with one Se(2)CaNd5 octahedra,  an edgeedge with one Se(4)CaNd5 octahedra,  an edgeedge with one Se(6)CaNd5 octahedra,  an edgeedge with one Se(7)CaNd5 octahedra,  an edgeedge with one Se(11)Nd6 octahedra,  an edgeedge with one Se(5)Nd6 octahedra,  a faceface with one Se(10)CaNd5 octahedra,  a faceface with one Se(4)CaNd5 octahedra,  a faceface with one Se(8)CaNd5 octahedra,  a faceface with one Se(9)CaNd5 octahedra, and  a faceface with one Se(1)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the fourth Se site, Se(4) is bonded to one Ca(1), one Nd(1), one Nd(2), one Nd(3), one Nd(4), and one Nd(8) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(9)CaNd5 octahedra,  a cornercorner with one Se(5)Nd6 octahedra, corners with two equivalent Se(10)CaNd5 octahedra, corners with two equivalent Se(2)CaNd5 octahedra, corners with two equivalent Se(6)CaNd5 octahedra, corners with two equivalent Se(8)CaNd5 octahedra, corners with two equivalent Se(1)Nd6 octahedra, corners with three equivalent Se(11)Nd6 octahedra,  an edgeedge with one Se(10)CaNd5 octahedra,  an edgeedge with one Se(2)CaNd5 octahedra,  an edgeedge with one Se(3)CaNd5 octahedra,  an edgeedge with one Se(6)CaNd5 octahedra,  an edgeedge with one Se(9)CaNd5 octahedra,  an edgeedge with one Se(1)Nd6 octahedra,  a faceface with one Se(3)CaNd5 octahedra,  a faceface with one Se(7)CaNd5 octahedra,  a faceface with one Se(8)CaNd5 octahedra,  a faceface with one Se(12)Nd6 octahedra, and  a faceface with one Se(5)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the fifth Se site, Se(5) is bonded to one Nd(1), one Nd(2), one Nd(3), one Nd(4), one Nd(5), and one Nd(7) atom to form distorted SeNd6 octahedra that share  a cornercorner with one Se(4)CaNd5 octahedra,  a cornercorner with one Se(6)CaNd5 octahedra, corners with two equivalent Se(3)CaNd5 octahedra, corners with two equivalent Se(7)CaNd5 octahedra, corners with two equivalent Se(9)CaNd5 octahedra, corners with two equivalent Se(11)Nd6 octahedra, corners with two equivalent Se(12)Nd6 octahedra, corners with three equivalent Se(8)CaNd5 octahedra,  an edgeedge with one Se(3)CaNd5 octahedra,  an edgeedge with one Se(6)CaNd5 octahedra,  an edgeedge with one Se(7)CaNd5 octahedra,  an edgeedge with one Se(9)CaNd5 octahedra,  an edgeedge with one Se(1)Nd6 octahedra,  an edgeedge with one Se(12)Nd6 octahedra,  a faceface with one Se(10)CaNd5 octahedra,  a faceface with one Se(2)CaNd5 octahedra,  a faceface with one Se(4)CaNd5 octahedra,  a faceface with one Se(1)Nd6 octahedra, and  a faceface with one Se(11)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the sixth Se site, Se(6) is bonded to one Ca(1), one Nd(3), one Nd(4), one Nd(5), one Nd(6), and one Nd(8) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(3)CaNd5 octahedra,  a cornercorner with one Se(8)CaNd5 octahedra,  a cornercorner with one Se(9)CaNd5 octahedra,  a cornercorner with one Se(1)Nd6 octahedra,  a cornercorner with one Se(11)Nd6 octahedra,  a cornercorner with one Se(5)Nd6 octahedra, corners with two equivalent Se(10)CaNd5 octahedra, corners with two equivalent Se(2)CaNd5 octahedra, corners with two equivalent Se(4)CaNd5 octahedra, corners with three equivalent Se(7)CaNd5 octahedra,  an edgeedge with one Se(10)CaNd5 octahedra,  an edgeedge with one Se(3)CaNd5 octahedra,  an edgeedge with one Se(4)CaNd5 octahedra,  an edgeedge with one Se(11)Nd6 octahedra,  an edgeedge with one Se(12)Nd6 octahedra,  an edgeedge with one Se(5)Nd6 octahedra,  a faceface with one Se(2)CaNd5 octahedra,  a faceface with one Se(8)CaNd5 octahedra,  a faceface with one Se(9)CaNd5 octahedra,  a faceface with one Se(1)Nd6 octahedra, and  a faceface with one Se(12)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the seventh Se site, Se(7) is bonded to one Ca(1), one Nd(1), one Nd(2), one Nd(5), one Nd(6), and one Nd(7) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(2)CaNd5 octahedra,  a cornercorner with one Se(1)Nd6 octahedra, corners with two equivalent Se(10)CaNd5 octahedra, corners with two equivalent Se(3)CaNd5 octahedra, corners with two equivalent Se(8)CaNd5 octahedra, corners with two equivalent Se(9)CaNd5 octahedra, corners with two equivalent Se(5)Nd6 octahedra, corners with three equivalent Se(6)CaNd5 octahedra,  an edgeedge with one Se(10)CaNd5 octahedra,  an edgeedge with one Se(3)CaNd5 octahedra,  an edgeedge with one Se(8)CaNd5 octahedra,  an edgeedge with one Se(1)Nd6 octahedra,  an edgeedge with one Se(11)Nd6 octahedra,  an edgeedge with one Se(5)Nd6 octahedra,  a faceface with one Se(2)CaNd5 octahedra,  a faceface with one Se(4)CaNd5 octahedra,  a faceface with one Se(9)CaNd5 octahedra,  a faceface with one Se(11)Nd6 octahedra, and  a faceface with one Se(12)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the eighth Se site, Se(8) is bonded to one Ca(1), one Nd(1), one Nd(2), one Nd(4), one Nd(6), and one Nd(8) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(3)CaNd5 octahedra,  a cornercorner with one Se(6)CaNd5 octahedra,  a cornercorner with one Se(9)CaNd5 octahedra,  a cornercorner with one Se(1)Nd6 octahedra,  a cornercorner with one Se(11)Nd6 octahedra,  a cornercorner with one Se(12)Nd6 octahedra, corners with two equivalent Se(10)CaNd5 octahedra, corners with two equivalent Se(4)CaNd5 octahedra, corners with two equivalent Se(7)CaNd5 octahedra, corners with three equivalent Se(5)Nd6 octahedra,  an edgeedge with one Se(10)CaNd5 octahedra,  an edgeedge with one Se(2)CaNd5 octahedra,  an edgeedge with one Se(7)CaNd5 octahedra,  an edgeedge with one Se(9)CaNd5 octahedra,  an edgeedge with one Se(1)Nd6 octahedra,  an edgeedge with one Se(12)Nd6 octahedra,  a faceface with one Se(2)CaNd5 octahedra,  a faceface with one Se(3)CaNd5 octahedra,  a faceface with one Se(4)CaNd5 octahedra,  a faceface with one Se(6)CaNd5 octahedra, and  a faceface with one Se(11)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the ninth Se site, Se(9) is bonded to one Ca(1), one Nd(2), one Nd(3), one Nd(5), one Nd(6), and one Nd(7) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(3)CaNd5 octahedra,  a cornercorner with one Se(4)CaNd5 octahedra,  a cornercorner with one Se(6)CaNd5 octahedra,  a cornercorner with one Se(8)CaNd5 octahedra,  a cornercorner with one Se(1)Nd6 octahedra,  a cornercorner with one Se(11)Nd6 octahedra, corners with two equivalent Se(7)CaNd5 octahedra, corners with two equivalent Se(12)Nd6 octahedra, corners with two equivalent Se(5)Nd6 octahedra, corners with three equivalent Se(2)CaNd5 octahedra,  an edgeedge with one Se(10)CaNd5 octahedra,  an edgeedge with one Se(4)CaNd5 octahedra,  an edgeedge with one Se(8)CaNd5 octahedra,  an edgeedge with one Se(1)Nd6 octahedra,  an edgeedge with one Se(12)Nd6 octahedra,  an edgeedge with one Se(5)Nd6 octahedra,  a faceface with one Se(10)CaNd5 octahedra,  a faceface with one Se(3)CaNd5 octahedra,  a faceface with one Se(6)CaNd5 octahedra,  a faceface with one Se(7)CaNd5 octahedra, and  a faceface with one Se(11)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the tenth Se site, Se(10) is bonded to one Ca(1), one Nd(2), one Nd(3), one Nd(6), one Nd(7), and one Nd(8) atom to form distorted SeCaNd5 octahedra that share  a cornercorner with one Se(11)Nd6 octahedra,  a cornercorner with one Se(12)Nd6 octahedra, corners with two equivalent Se(3)CaNd5 octahedra, corners with two equivalent Se(4)CaNd5 octahedra, corners with two equivalent Se(6)CaNd5 octahedra, corners with two equivalent Se(7)CaNd5 octahedra, corners with two equivalent Se(8)CaNd5 octahedra, corners with three equivalent Se(1)Nd6 octahedra,  an edgeedge with one Se(4)CaNd5 octahedra,  an edgeedge with one Se(6)CaNd5 octahedra,  an edgeedge with one Se(7)CaNd5 octahedra,  an edgeedge with one Se(8)CaNd5 octahedra,  an edgeedge with one Se(9)CaNd5 octahedra,  an edgeedge with one Se(11)Nd6 octahedra,  a faceface with one Se(2)CaNd5 octahedra,  a faceface with one Se(3)CaNd5 octahedra,  a faceface with one Se(9)CaNd5 octahedra,  a faceface with one Se(12)Nd6 octahedra, and  a faceface with one Se(5)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the eleventh Se site, Se(11) is bonded to one Nd(1), one Nd(2), one Nd(4), one Nd(5), one Nd(6), and one Nd(7) atom to form distorted SeNd6 octahedra that share  a cornercorner with one Se(10)CaNd5 octahedra,  a cornercorner with one Se(3)CaNd5 octahedra,  a cornercorner with one Se(6)CaNd5 octahedra,  a cornercorner with one Se(8)CaNd5 octahedra,  a cornercorner with one Se(9)CaNd5 octahedra,  a cornercorner with one Se(1)Nd6 octahedra, corners with two equivalent Se(2)CaNd5 octahedra, corners with two equivalent Se(12)Nd6 octahedra, corners with two equivalent Se(5)Nd6 octahedra, corners with three equivalent Se(4)CaNd5 octahedra,  an edgeedge with one Se(10)CaNd5 octahedra,  an edgeedge with one Se(2)CaNd5 octahedra,  an edgeedge with one Se(3)CaNd5 octahedra,  an edgeedge with one Se(6)CaNd5 octahedra,  an edgeedge with one Se(7)CaNd5 octahedra,  an edgeedge with one Se(12)Nd6 octahedra,  a faceface with one Se(7)CaNd5 octahedra,  a faceface with one Se(8)CaNd5 octahedra,  a faceface with one Se(9)CaNd5 octahedra,  a faceface with one Se(1)Nd6 octahedra, and  a faceface with one Se(5)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the twelfth Se site, Se(12) is bonded to one Nd(3), one Nd(4), one Nd(5), one Nd(6), one Nd(7), and one Nd(8) atom to form distorted SeNd6 octahedra that share  a cornercorner with one Se(10)CaNd5 octahedra,  a cornercorner with one Se(8)CaNd5 octahedra, corners with two equivalent Se(2)CaNd5 octahedra, corners with two equivalent Se(9)CaNd5 octahedra, corners with two equivalent Se(1)Nd6 octahedra, corners with two equivalent Se(11)Nd6 octahedra, corners with two equivalent Se(5)Nd6 octahedra, corners with three equivalent Se(3)CaNd5 octahedra,  an edgeedge with one Se(2)CaNd5 octahedra,  an edgeedge with one Se(6)CaNd5 octahedra,  an edgeedge with one Se(8)CaNd5 octahedra,  an edgeedge with one Se(9)CaNd5 octahedra,  an edgeedge with one Se(11)Nd6 octahedra,  an edgeedge with one Se(5)Nd6 octahedra,  a faceface with one Se(10)CaNd5 octahedra,  a faceface with one Se(4)CaNd5 octahedra,  a faceface with one Se(6)CaNd5 octahedra,  a faceface with one Se(7)CaNd5 octahedra, and  a faceface with one Se(1)Nd6 octahedra. The corner-sharing octahedral tilt angles range from 16-50°.