Ca(Pr2Se3)4 crystallizes in the monoclinic Cc space group. Ca(1) is bonded to one Se(1), one Se(11), one Se(2), one Se(3), 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 Pr(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(2)Se8 hexagonal bipyramid,  a cornercorner with one Pr(5)Se8 hexagonal bipyramid,  a cornercorner with one Pr(6)Se8 hexagonal bipyramid, corners with two equivalent Pr(3)Se8 hexagonal bipyramids, corners with two equivalent Pr(4)Se8 hexagonal bipyramids,  an edgeedge with one Pr(1)Se8 hexagonal bipyramid,  an edgeedge with one Pr(5)Se8 hexagonal bipyramid, edges with two equivalent Pr(7)Se8 hexagonal bipyramids,  a faceface with one Pr(1)Se8 hexagonal bipyramid,  a faceface with one Pr(2)Se8 hexagonal bipyramid,  a faceface with one Pr(3)Se8 hexagonal bipyramid,  a faceface with one Pr(4)Se8 hexagonal bipyramid,  a faceface with one Pr(5)Se8 hexagonal bipyramid,  a faceface with one Pr(6)Se8 hexagonal bipyramid, and faces with two equivalent Pr(8)Se8 hexagonal bipyramids. There are eight inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one Se(1), one Se(11), one Se(12), one Se(2), one Se(3), one Se(4), one Se(7), and one Se(9) atom to form distorted PrSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(5)Se8 hexagonal bipyramid,  a cornercorner with one Pr(6)Se8 hexagonal bipyramid,  a cornercorner with one Pr(7)Se8 hexagonal bipyramid, corners with two equivalent Pr(3)Se8 hexagonal bipyramids, corners with two equivalent Pr(8)Se8 hexagonal bipyramids,  an edgeedge with one Ca(1)Se8 hexagonal bipyramid,  an edgeedge with one Pr(6)Se8 hexagonal bipyramid, edges with two equivalent Pr(2)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Pr(3)Se8 hexagonal bipyramid,  a faceface with one Pr(5)Se8 hexagonal bipyramid,  a faceface with one Pr(6)Se8 hexagonal bipyramid,  a faceface with one Pr(7)Se8 hexagonal bipyramid,  a faceface with one Pr(8)Se8 hexagonal bipyramid, and faces with two equivalent Pr(4)Se8 hexagonal bipyramids. In the second Pr site, Pr(2) is bonded to one Se(10), one Se(12), one Se(2), one Se(4), one Se(5), one Se(6), one Se(8), and one Se(9) atom to form distorted PrSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(5)Se8 hexagonal bipyramid,  a cornercorner with one Pr(6)Se8 hexagonal bipyramid,  a cornercorner with one Pr(7)Se8 hexagonal bipyramid, corners with two equivalent Pr(3)Se8 hexagonal bipyramids, corners with two equivalent Pr(8)Se8 hexagonal bipyramids,  an edgeedge with one Pr(5)Se8 hexagonal bipyramid,  an edgeedge with one Pr(7)Se8 hexagonal bipyramid, edges with two equivalent Pr(1)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Pr(3)Se8 hexagonal bipyramid,  a faceface with one Pr(5)Se8 hexagonal bipyramid,  a faceface with one Pr(6)Se8 hexagonal bipyramid,  a faceface with one Pr(7)Se8 hexagonal bipyramid,  a faceface with one Pr(8)Se8 hexagonal bipyramid, and faces with two equivalent Pr(4)Se8 hexagonal bipyramids. In the third Pr site, Pr(3) is bonded to one Se(1), one Se(10), one Se(11), one Se(2), one Se(3), one Se(4), one Se(5), and one Se(6) atom to form distorted PrSe8 hexagonal bipyramids that share corners with two equivalent Ca(1)Se8 hexagonal bipyramids, corners with two equivalent Pr(1)Se8 hexagonal bipyramids, corners with two equivalent Pr(2)Se8 hexagonal bipyramids, corners with two equivalent Pr(7)Se8 hexagonal bipyramids, edges with two equivalent Pr(4)Se8 hexagonal bipyramids, edges with two equivalent Pr(8)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Pr(1)Se8 hexagonal bipyramid,  a faceface with one Pr(2)Se8 hexagonal bipyramid,  a faceface with one Pr(7)Se8 hexagonal bipyramid, faces with two equivalent Pr(5)Se8 hexagonal bipyramids, and faces with two equivalent Pr(6)Se8 hexagonal bipyramids. In the fourth Pr site, Pr(4) is bonded to one Se(12), one Se(2), one Se(3), one Se(4), one Se(5), one Se(7), one Se(8), and one Se(9) atom to form distorted PrSe8 hexagonal bipyramids that share corners with two equivalent Ca(1)Se8 hexagonal bipyramids, corners with two equivalent Pr(5)Se8 hexagonal bipyramids, corners with two equivalent Pr(6)Se8 hexagonal bipyramids, corners with two equivalent Pr(7)Se8 hexagonal bipyramids, edges with two equivalent Pr(3)Se8 hexagonal bipyramids, edges with two equivalent Pr(8)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Pr(5)Se8 hexagonal bipyramid,  a faceface with one Pr(6)Se8 hexagonal bipyramid,  a faceface with one Pr(7)Se8 hexagonal bipyramid, faces with two equivalent Pr(1)Se8 hexagonal bipyramids, and faces with two equivalent Pr(2)Se8 hexagonal bipyramids. In the fifth Pr site, Pr(5) is bonded to one Se(10), one Se(11), one Se(2), one Se(3), one Se(5), one Se(6), one Se(8), and one Se(9) atom to form distorted PrSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(2)Se8 hexagonal bipyramid,  a cornercorner with one Pr(7)Se8 hexagonal bipyramid, corners with two equivalent Pr(4)Se8 hexagonal bipyramids, corners with two equivalent Pr(8)Se8 hexagonal bipyramids,  an edgeedge with one Ca(1)Se8 hexagonal bipyramid,  an edgeedge with one Pr(2)Se8 hexagonal bipyramid, edges with two equivalent Pr(6)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Pr(1)Se8 hexagonal bipyramid,  a faceface with one Pr(2)Se8 hexagonal bipyramid,  a faceface with one Pr(4)Se8 hexagonal bipyramid,  a faceface with one Pr(7)Se8 hexagonal bipyramid,  a faceface with one Pr(8)Se8 hexagonal bipyramid, and faces with two equivalent Pr(3)Se8 hexagonal bipyramids. In the sixth Pr site, Pr(6) is bonded to one Se(1), one Se(10), one Se(11), one Se(12), one Se(3), one Se(4), one Se(5), and one Se(7) atom to form distorted PrSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(2)Se8 hexagonal bipyramid,  a cornercorner with one Pr(7)Se8 hexagonal bipyramid, corners with two equivalent Pr(4)Se8 hexagonal bipyramids, corners with two equivalent Pr(8)Se8 hexagonal bipyramids,  an edgeedge with one Pr(1)Se8 hexagonal bipyramid,  an edgeedge with one Pr(7)Se8 hexagonal bipyramid, edges with two equivalent Pr(5)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Pr(1)Se8 hexagonal bipyramid,  a faceface with one Pr(2)Se8 hexagonal bipyramid,  a faceface with one Pr(4)Se8 hexagonal bipyramid,  a faceface with one Pr(7)Se8 hexagonal bipyramid,  a faceface with one Pr(8)Se8 hexagonal bipyramid, and faces with two equivalent Pr(3)Se8 hexagonal bipyramids. In the seventh Pr site, Pr(7) is bonded to one Se(1), one Se(10), one Se(12), one Se(4), one Se(5), one Se(6), one Se(7), and one Se(8) atom to form distorted PrSe8 hexagonal bipyramids that share  a cornercorner with one Pr(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(2)Se8 hexagonal bipyramid,  a cornercorner with one Pr(5)Se8 hexagonal bipyramid,  a cornercorner with one Pr(6)Se8 hexagonal bipyramid, corners with two equivalent Pr(3)Se8 hexagonal bipyramids, corners with two equivalent Pr(4)Se8 hexagonal bipyramids,  an edgeedge with one Pr(2)Se8 hexagonal bipyramid,  an edgeedge with one Pr(6)Se8 hexagonal bipyramid, edges with two equivalent Ca(1)Se8 hexagonal bipyramids,  a faceface with one Pr(1)Se8 hexagonal bipyramid,  a faceface with one Pr(2)Se8 hexagonal bipyramid,  a faceface with one Pr(3)Se8 hexagonal bipyramid,  a faceface with one Pr(4)Se8 hexagonal bipyramid,  a faceface with one Pr(5)Se8 hexagonal bipyramid,  a faceface with one Pr(6)Se8 hexagonal bipyramid, and faces with two equivalent Pr(8)Se8 hexagonal bipyramids. In the eighth Pr site, Pr(8) is bonded to one Se(1), one Se(10), one Se(11), one Se(12), one Se(6), one Se(7), one Se(8), and one Se(9) atom to form distorted PrSe8 hexagonal bipyramids that share corners with two equivalent Pr(1)Se8 hexagonal bipyramids, corners with two equivalent Pr(2)Se8 hexagonal bipyramids, corners with two equivalent Pr(5)Se8 hexagonal bipyramids, corners with two equivalent Pr(6)Se8 hexagonal bipyramids, edges with two equivalent Pr(3)Se8 hexagonal bipyramids, edges with two equivalent Pr(4)Se8 hexagonal bipyramids,  a faceface with one Pr(1)Se8 hexagonal bipyramid,  a faceface with one Pr(2)Se8 hexagonal bipyramid,  a faceface with one Pr(5)Se8 hexagonal bipyramid,  a faceface with one Pr(6)Se8 hexagonal bipyramid, faces with two equivalent Ca(1)Se8 hexagonal bipyramids, and faces with two equivalent Pr(7)Se8 hexagonal bipyramids. There are twelve inequivalent Se sites. In the first Se site, Se(1) is bonded to one Ca(1), one Pr(1), one Pr(3), one Pr(6), one Pr(7), and one Pr(8) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(2)CaPr5 octahedra,  a cornercorner with one Se(6)CaPr5 octahedra, corners with two equivalent Se(3)CaPr5 octahedra, corners with two equivalent Se(7)CaPr5 octahedra, corners with two equivalent Se(10)Pr6 octahedra, corners with two equivalent Se(12)Pr6 octahedra, corners with two equivalent Se(4)Pr6 octahedra, corners with three equivalent Se(8)CaPr5 octahedra,  an edgeedge with one Se(11)CaPr5 octahedra,  an edgeedge with one Se(2)CaPr5 octahedra,  an edgeedge with one Se(3)CaPr5 octahedra,  an edgeedge with one Se(10)Pr6 octahedra,  an edgeedge with one Se(12)Pr6 octahedra,  an edgeedge with one Se(4)Pr6 octahedra,  a faceface with one Se(11)CaPr5 octahedra,  a faceface with one Se(6)CaPr5 octahedra,  a faceface with one Se(7)CaPr5 octahedra,  a faceface with one Se(9)CaPr5 octahedra, and  a faceface with one Se(5)Pr6 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 Pr(1), one Pr(2), one Pr(3), one Pr(4), and one Pr(5) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(1)CaPr5 octahedra,  a cornercorner with one Se(11)CaPr5 octahedra,  a cornercorner with one Se(7)CaPr5 octahedra,  a cornercorner with one Se(8)CaPr5 octahedra,  a cornercorner with one Se(10)Pr6 octahedra,  a cornercorner with one Se(4)Pr6 octahedra, corners with two equivalent Se(6)CaPr5 octahedra, corners with two equivalent Se(9)CaPr5 octahedra, corners with two equivalent Se(5)Pr6 octahedra, corners with three equivalent Se(12)Pr6 octahedra,  an edgeedge with one Se(1)CaPr5 octahedra,  an edgeedge with one Se(3)CaPr5 octahedra,  an edgeedge with one Se(6)CaPr5 octahedra,  an edgeedge with one Se(7)CaPr5 octahedra,  an edgeedge with one Se(10)Pr6 octahedra,  an edgeedge with one Se(5)Pr6 octahedra,  a faceface with one Se(11)CaPr5 octahedra,  a faceface with one Se(3)CaPr5 octahedra,  a faceface with one Se(8)CaPr5 octahedra,  a faceface with one Se(9)CaPr5 octahedra, and  a faceface with one Se(4)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 17-51°. In the third Se site, Se(3) is bonded to one Ca(1), one Pr(1), one Pr(3), one Pr(4), one Pr(5), and one Pr(6) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(8)CaPr5 octahedra,  a cornercorner with one Se(5)Pr6 octahedra, corners with two equivalent Se(1)CaPr5 octahedra, corners with two equivalent Se(11)CaPr5 octahedra, corners with two equivalent Se(7)CaPr5 octahedra, corners with two equivalent Se(9)CaPr5 octahedra, corners with two equivalent Se(4)Pr6 octahedra, corners with three equivalent Se(10)Pr6 octahedra,  an edgeedge with one Se(1)CaPr5 octahedra,  an edgeedge with one Se(2)CaPr5 octahedra,  an edgeedge with one Se(7)CaPr5 octahedra,  an edgeedge with one Se(8)CaPr5 octahedra,  an edgeedge with one Se(9)CaPr5 octahedra,  an edgeedge with one Se(4)Pr6 octahedra,  a faceface with one Se(11)CaPr5 octahedra,  a faceface with one Se(2)CaPr5 octahedra,  a faceface with one Se(6)CaPr5 octahedra,  a faceface with one Se(12)Pr6 octahedra, and  a faceface with one Se(5)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the fourth Se site, Se(4) is bonded to one Pr(1), one Pr(2), one Pr(3), one Pr(4), one Pr(6), and one Pr(7) atom to form distorted SePr6 octahedra that share  a cornercorner with one Se(11)CaPr5 octahedra,  a cornercorner with one Se(2)CaPr5 octahedra,  a cornercorner with one Se(6)CaPr5 octahedra,  a cornercorner with one Se(7)CaPr5 octahedra,  a cornercorner with one Se(8)CaPr5 octahedra,  a cornercorner with one Se(10)Pr6 octahedra, corners with two equivalent Se(1)CaPr5 octahedra, corners with two equivalent Se(3)CaPr5 octahedra, corners with two equivalent Se(12)Pr6 octahedra, corners with three equivalent Se(9)CaPr5 octahedra,  an edgeedge with one Se(1)CaPr5 octahedra,  an edgeedge with one Se(11)CaPr5 octahedra,  an edgeedge with one Se(3)CaPr5 octahedra,  an edgeedge with one Se(6)CaPr5 octahedra,  an edgeedge with one Se(8)CaPr5 octahedra,  an edgeedge with one Se(5)Pr6 octahedra,  a faceface with one Se(2)CaPr5 octahedra,  a faceface with one Se(7)CaPr5 octahedra,  a faceface with one Se(10)Pr6 octahedra,  a faceface with one Se(12)Pr6 octahedra, and  a faceface with one Se(5)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the fifth Se site, Se(5) is bonded to one Pr(2), one Pr(3), one Pr(4), one Pr(5), one Pr(6), and one Pr(7) atom to form distorted SePr6 octahedra that share  a cornercorner with one Se(3)CaPr5 octahedra,  a cornercorner with one Se(7)CaPr5 octahedra, corners with two equivalent Se(2)CaPr5 octahedra, corners with two equivalent Se(6)CaPr5 octahedra, corners with two equivalent Se(8)CaPr5 octahedra, corners with two equivalent Se(10)Pr6 octahedra, corners with two equivalent Se(12)Pr6 octahedra, corners with three equivalent Se(11)CaPr5 octahedra,  an edgeedge with one Se(2)CaPr5 octahedra,  an edgeedge with one Se(6)CaPr5 octahedra,  an edgeedge with one Se(7)CaPr5 octahedra,  an edgeedge with one Se(8)CaPr5 octahedra,  an edgeedge with one Se(12)Pr6 octahedra,  an edgeedge with one Se(4)Pr6 octahedra,  a faceface with one Se(1)CaPr5 octahedra,  a faceface with one Se(3)CaPr5 octahedra,  a faceface with one Se(9)CaPr5 octahedra,  a faceface with one Se(10)Pr6 octahedra, and  a faceface with one Se(4)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 16-51°. In the sixth Se site, Se(6) is bonded to one Ca(1), one Pr(2), one Pr(3), one Pr(5), one Pr(7), and one Pr(8) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(1)CaPr5 octahedra,  a cornercorner with one Se(4)Pr6 octahedra, corners with two equivalent Se(11)CaPr5 octahedra, corners with two equivalent Se(2)CaPr5 octahedra, corners with two equivalent Se(8)CaPr5 octahedra, corners with two equivalent Se(9)CaPr5 octahedra, corners with two equivalent Se(5)Pr6 octahedra, corners with three equivalent Se(7)CaPr5 octahedra,  an edgeedge with one Se(11)CaPr5 octahedra,  an edgeedge with one Se(2)CaPr5 octahedra,  an edgeedge with one Se(9)CaPr5 octahedra,  an edgeedge with one Se(10)Pr6 octahedra,  an edgeedge with one Se(4)Pr6 octahedra,  an edgeedge with one Se(5)Pr6 octahedra,  a faceface with one Se(1)CaPr5 octahedra,  a faceface with one Se(3)CaPr5 octahedra,  a faceface with one Se(8)CaPr5 octahedra,  a faceface with one Se(10)Pr6 octahedra, and  a faceface with one Se(12)Pr6 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 Pr(1), one Pr(4), one Pr(6), one Pr(7), and one Pr(8) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(11)CaPr5 octahedra,  a cornercorner with one Se(2)CaPr5 octahedra,  a cornercorner with one Se(8)CaPr5 octahedra,  a cornercorner with one Se(10)Pr6 octahedra,  a cornercorner with one Se(4)Pr6 octahedra,  a cornercorner with one Se(5)Pr6 octahedra, corners with two equivalent Se(1)CaPr5 octahedra, corners with two equivalent Se(3)CaPr5 octahedra, corners with two equivalent Se(9)CaPr5 octahedra, corners with three equivalent Se(6)CaPr5 octahedra,  an edgeedge with one Se(2)CaPr5 octahedra,  an edgeedge with one Se(3)CaPr5 octahedra,  an edgeedge with one Se(9)CaPr5 octahedra,  an edgeedge with one Se(10)Pr6 octahedra,  an edgeedge with one Se(12)Pr6 octahedra,  an edgeedge with one Se(5)Pr6 octahedra,  a faceface with one Se(1)CaPr5 octahedra,  a faceface with one Se(11)CaPr5 octahedra,  a faceface with one Se(8)CaPr5 octahedra,  a faceface with one Se(12)Pr6 octahedra, and  a faceface with one Se(4)Pr6 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 Pr(2), one Pr(4), one Pr(5), one Pr(7), and one Pr(8) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(11)CaPr5 octahedra,  a cornercorner with one Se(2)CaPr5 octahedra,  a cornercorner with one Se(3)CaPr5 octahedra,  a cornercorner with one Se(7)CaPr5 octahedra,  a cornercorner with one Se(10)Pr6 octahedra,  a cornercorner with one Se(4)Pr6 octahedra, corners with two equivalent Se(6)CaPr5 octahedra, corners with two equivalent Se(12)Pr6 octahedra, corners with two equivalent Se(5)Pr6 octahedra, corners with three equivalent Se(1)CaPr5 octahedra,  an edgeedge with one Se(11)CaPr5 octahedra,  an edgeedge with one Se(3)CaPr5 octahedra,  an edgeedge with one Se(9)CaPr5 octahedra,  an edgeedge with one Se(12)Pr6 octahedra,  an edgeedge with one Se(4)Pr6 octahedra,  an edgeedge with one Se(5)Pr6 octahedra,  a faceface with one Se(2)CaPr5 octahedra,  a faceface with one Se(6)CaPr5 octahedra,  a faceface with one Se(7)CaPr5 octahedra,  a faceface with one Se(9)CaPr5 octahedra, and  a faceface with one Se(10)Pr6 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 Pr(1), one Pr(2), one Pr(4), one Pr(5), and one Pr(8) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(10)Pr6 octahedra,  a cornercorner with one Se(12)Pr6 octahedra, corners with two equivalent Se(11)CaPr5 octahedra, corners with two equivalent Se(2)CaPr5 octahedra, corners with two equivalent Se(3)CaPr5 octahedra, corners with two equivalent Se(6)CaPr5 octahedra, corners with two equivalent Se(7)CaPr5 octahedra, corners with three equivalent Se(4)Pr6 octahedra,  an edgeedge with one Se(11)CaPr5 octahedra,  an edgeedge with one Se(3)CaPr5 octahedra,  an edgeedge with one Se(6)CaPr5 octahedra,  an edgeedge with one Se(7)CaPr5 octahedra,  an edgeedge with one Se(8)CaPr5 octahedra,  an edgeedge with one Se(10)Pr6 octahedra,  a faceface with one Se(1)CaPr5 octahedra,  a faceface with one Se(2)CaPr5 octahedra,  a faceface with one Se(8)CaPr5 octahedra,  a faceface with one Se(12)Pr6 octahedra, and  a faceface with one Se(5)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the tenth Se site, Se(10) is bonded to one Pr(2), one Pr(3), one Pr(5), one Pr(6), one Pr(7), and one Pr(8) atom to form distorted SePr6 octahedra that share  a cornercorner with one Se(11)CaPr5 octahedra,  a cornercorner with one Se(2)CaPr5 octahedra,  a cornercorner with one Se(7)CaPr5 octahedra,  a cornercorner with one Se(8)CaPr5 octahedra,  a cornercorner with one Se(9)CaPr5 octahedra,  a cornercorner with one Se(4)Pr6 octahedra, corners with two equivalent Se(1)CaPr5 octahedra, corners with two equivalent Se(12)Pr6 octahedra, corners with two equivalent Se(5)Pr6 octahedra, corners with three equivalent Se(3)CaPr5 octahedra,  an edgeedge with one Se(1)CaPr5 octahedra,  an edgeedge with one Se(2)CaPr5 octahedra,  an edgeedge with one Se(6)CaPr5 octahedra,  an edgeedge with one Se(7)CaPr5 octahedra,  an edgeedge with one Se(9)CaPr5 octahedra,  an edgeedge with one Se(12)Pr6 octahedra,  a faceface with one Se(11)CaPr5 octahedra,  a faceface with one Se(6)CaPr5 octahedra,  a faceface with one Se(8)CaPr5 octahedra,  a faceface with one Se(4)Pr6 octahedra, and  a faceface with one Se(5)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the eleventh Se site, Se(11) is bonded to one Ca(1), one Pr(1), one Pr(3), one Pr(5), one Pr(6), and one Pr(8) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(2)CaPr5 octahedra,  a cornercorner with one Se(7)CaPr5 octahedra,  a cornercorner with one Se(8)CaPr5 octahedra,  a cornercorner with one Se(10)Pr6 octahedra,  a cornercorner with one Se(12)Pr6 octahedra,  a cornercorner with one Se(4)Pr6 octahedra, corners with two equivalent Se(3)CaPr5 octahedra, corners with two equivalent Se(6)CaPr5 octahedra, corners with two equivalent Se(9)CaPr5 octahedra, corners with three equivalent Se(5)Pr6 octahedra,  an edgeedge with one Se(1)CaPr5 octahedra,  an edgeedge with one Se(6)CaPr5 octahedra,  an edgeedge with one Se(8)CaPr5 octahedra,  an edgeedge with one Se(9)CaPr5 octahedra,  an edgeedge with one Se(12)Pr6 octahedra,  an edgeedge with one Se(4)Pr6 octahedra,  a faceface with one Se(1)CaPr5 octahedra,  a faceface with one Se(2)CaPr5 octahedra,  a faceface with one Se(3)CaPr5 octahedra,  a faceface with one Se(7)CaPr5 octahedra, and  a faceface with one Se(10)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 17-51°. In the twelfth Se site, Se(12) is bonded to one Pr(1), one Pr(2), one Pr(4), one Pr(6), one Pr(7), and one Pr(8) atom to form distorted SePr6 octahedra that share  a cornercorner with one Se(11)CaPr5 octahedra,  a cornercorner with one Se(9)CaPr5 octahedra, corners with two equivalent Se(1)CaPr5 octahedra, corners with two equivalent Se(8)CaPr5 octahedra, corners with two equivalent Se(10)Pr6 octahedra, corners with two equivalent Se(4)Pr6 octahedra, corners with two equivalent Se(5)Pr6 octahedra, corners with three equivalent Se(2)CaPr5 octahedra,  an edgeedge with one Se(1)CaPr5 octahedra,  an edgeedge with one Se(11)CaPr5 octahedra,  an edgeedge with one Se(7)CaPr5 octahedra,  an edgeedge with one Se(8)CaPr5 octahedra,  an edgeedge with one Se(10)Pr6 octahedra,  an edgeedge with one Se(5)Pr6 octahedra,  a faceface with one Se(3)CaPr5 octahedra,  a faceface with one Se(6)CaPr5 octahedra,  a faceface with one Se(7)CaPr5 octahedra,  a faceface with one Se(9)CaPr5 octahedra, and  a faceface with one Se(4)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 16-51°.
Ca(Pr2Se3)4 crystallizes in the monoclinic Cc space group. Ca(1) is bonded to one Se(1), one Se(11), one Se(2), one Se(3), 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 Pr(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(2)Se8 hexagonal bipyramid,  a cornercorner with one Pr(5)Se8 hexagonal bipyramid,  a cornercorner with one Pr(6)Se8 hexagonal bipyramid, corners with two equivalent Pr(3)Se8 hexagonal bipyramids, corners with two equivalent Pr(4)Se8 hexagonal bipyramids,  an edgeedge with one Pr(1)Se8 hexagonal bipyramid,  an edgeedge with one Pr(5)Se8 hexagonal bipyramid, edges with two equivalent Pr(7)Se8 hexagonal bipyramids,  a faceface with one Pr(1)Se8 hexagonal bipyramid,  a faceface with one Pr(2)Se8 hexagonal bipyramid,  a faceface with one Pr(3)Se8 hexagonal bipyramid,  a faceface with one Pr(4)Se8 hexagonal bipyramid,  a faceface with one Pr(5)Se8 hexagonal bipyramid,  a faceface with one Pr(6)Se8 hexagonal bipyramid, and faces with two equivalent Pr(8)Se8 hexagonal bipyramids. The Ca(1)-Se(1) bond length is 3.23 Å. The Ca(1)-Se(11) bond length is 3.01 Å. The Ca(1)-Se(2) bond length is 3.23 Å. The Ca(1)-Se(3) bond length is 3.24 Å. The Ca(1)-Se(6) bond length is 3.01 Å. The Ca(1)-Se(7) bond length is 3.24 Å. The Ca(1)-Se(8) bond length is 3.01 Å. The Ca(1)-Se(9) bond length is 3.02 Å. There are eight inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one Se(1), one Se(11), one Se(12), one Se(2), one Se(3), one Se(4), one Se(7), and one Se(9) atom to form distorted PrSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(5)Se8 hexagonal bipyramid,  a cornercorner with one Pr(6)Se8 hexagonal bipyramid,  a cornercorner with one Pr(7)Se8 hexagonal bipyramid, corners with two equivalent Pr(3)Se8 hexagonal bipyramids, corners with two equivalent Pr(8)Se8 hexagonal bipyramids,  an edgeedge with one Ca(1)Se8 hexagonal bipyramid,  an edgeedge with one Pr(6)Se8 hexagonal bipyramid, edges with two equivalent Pr(2)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Pr(3)Se8 hexagonal bipyramid,  a faceface with one Pr(5)Se8 hexagonal bipyramid,  a faceface with one Pr(6)Se8 hexagonal bipyramid,  a faceface with one Pr(7)Se8 hexagonal bipyramid,  a faceface with one Pr(8)Se8 hexagonal bipyramid, and faces with two equivalent Pr(4)Se8 hexagonal bipyramids. The Pr(1)-Se(1) bond length is 3.19 Å. The Pr(1)-Se(11) bond length is 3.19 Å. The Pr(1)-Se(12) bond length is 3.21 Å. The Pr(1)-Se(2) bond length is 3.02 Å. The Pr(1)-Se(3) bond length is 3.03 Å. The Pr(1)-Se(4) bond length is 3.23 Å. The Pr(1)-Se(7) bond length is 3.03 Å. The Pr(1)-Se(9) bond length is 3.03 Å. In the second Pr site, Pr(2) is bonded to one Se(10), one Se(12), one Se(2), one Se(4), one Se(5), one Se(6), one Se(8), and one Se(9) atom to form distorted PrSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(5)Se8 hexagonal bipyramid,  a cornercorner with one Pr(6)Se8 hexagonal bipyramid,  a cornercorner with one Pr(7)Se8 hexagonal bipyramid, corners with two equivalent Pr(3)Se8 hexagonal bipyramids, corners with two equivalent Pr(8)Se8 hexagonal bipyramids,  an edgeedge with one Pr(5)Se8 hexagonal bipyramid,  an edgeedge with one Pr(7)Se8 hexagonal bipyramid, edges with two equivalent Pr(1)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Pr(3)Se8 hexagonal bipyramid,  a faceface with one Pr(5)Se8 hexagonal bipyramid,  a faceface with one Pr(6)Se8 hexagonal bipyramid,  a faceface with one Pr(7)Se8 hexagonal bipyramid,  a faceface with one Pr(8)Se8 hexagonal bipyramid, and faces with two equivalent Pr(4)Se8 hexagonal bipyramids. The Pr(2)-Se(10) bond length is 3.19 Å. The Pr(2)-Se(12) bond length is 3.04 Å. The Pr(2)-Se(2) bond length is 3.22 Å. The Pr(2)-Se(4) bond length is 3.03 Å. The Pr(2)-Se(5) bond length is 3.05 Å. The Pr(2)-Se(6) bond length is 3.21 Å. The Pr(2)-Se(8) bond length is 3.02 Å. The Pr(2)-Se(9) bond length is 3.21 Å. In the third Pr site, Pr(3) is bonded to one Se(1), one Se(10), one Se(11), one Se(2), one Se(3), one Se(4), one Se(5), and one Se(6) atom to form distorted PrSe8 hexagonal bipyramids that share corners with two equivalent Ca(1)Se8 hexagonal bipyramids, corners with two equivalent Pr(1)Se8 hexagonal bipyramids, corners with two equivalent Pr(2)Se8 hexagonal bipyramids, corners with two equivalent Pr(7)Se8 hexagonal bipyramids, edges with two equivalent Pr(4)Se8 hexagonal bipyramids, edges with two equivalent Pr(8)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Pr(1)Se8 hexagonal bipyramid,  a faceface with one Pr(2)Se8 hexagonal bipyramid,  a faceface with one Pr(7)Se8 hexagonal bipyramid, faces with two equivalent Pr(5)Se8 hexagonal bipyramids, and faces with two equivalent Pr(6)Se8 hexagonal bipyramids. The Pr(3)-Se(1) bond length is 3.02 Å. The Pr(3)-Se(10) bond length is 3.19 Å. The Pr(3)-Se(11) bond length is 3.22 Å. The Pr(3)-Se(2) bond length is 3.03 Å. The Pr(3)-Se(3) bond length is 3.20 Å. The Pr(3)-Se(4) bond length is 3.04 Å. The Pr(3)-Se(5) bond length is 3.21 Å. The Pr(3)-Se(6) bond length is 3.04 Å. In the fourth Pr site, Pr(4) is bonded to one Se(12), one Se(2), one Se(3), one Se(4), one Se(5), one Se(7), one Se(8), and one Se(9) atom to form distorted PrSe8 hexagonal bipyramids that share corners with two equivalent Ca(1)Se8 hexagonal bipyramids, corners with two equivalent Pr(5)Se8 hexagonal bipyramids, corners with two equivalent Pr(6)Se8 hexagonal bipyramids, corners with two equivalent Pr(7)Se8 hexagonal bipyramids, edges with two equivalent Pr(3)Se8 hexagonal bipyramids, edges with two equivalent Pr(8)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Pr(5)Se8 hexagonal bipyramid,  a faceface with one Pr(6)Se8 hexagonal bipyramid,  a faceface with one Pr(7)Se8 hexagonal bipyramid, faces with two equivalent Pr(1)Se8 hexagonal bipyramids, and faces with two equivalent Pr(2)Se8 hexagonal bipyramids. The Pr(4)-Se(12) bond length is 3.22 Å. The Pr(4)-Se(2) bond length is 3.20 Å. The Pr(4)-Se(3) bond length is 3.04 Å. The Pr(4)-Se(4) bond length is 3.21 Å. The Pr(4)-Se(5) bond length is 3.03 Å. The Pr(4)-Se(7) bond length is 3.03 Å. The Pr(4)-Se(8) bond length is 3.03 Å. The Pr(4)-Se(9) bond length is 3.20 Å. In the fifth Pr site, Pr(5) is bonded to one Se(10), one Se(11), one Se(2), one Se(3), one Se(5), one Se(6), one Se(8), and one Se(9) atom to form distorted PrSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(2)Se8 hexagonal bipyramid,  a cornercorner with one Pr(7)Se8 hexagonal bipyramid, corners with two equivalent Pr(4)Se8 hexagonal bipyramids, corners with two equivalent Pr(8)Se8 hexagonal bipyramids,  an edgeedge with one Ca(1)Se8 hexagonal bipyramid,  an edgeedge with one Pr(2)Se8 hexagonal bipyramid, edges with two equivalent Pr(6)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Pr(1)Se8 hexagonal bipyramid,  a faceface with one Pr(2)Se8 hexagonal bipyramid,  a faceface with one Pr(4)Se8 hexagonal bipyramid,  a faceface with one Pr(7)Se8 hexagonal bipyramid,  a faceface with one Pr(8)Se8 hexagonal bipyramid, and faces with two equivalent Pr(3)Se8 hexagonal bipyramids. The Pr(5)-Se(10) bond length is 3.04 Å. The Pr(5)-Se(11) bond length is 3.22 Å. The Pr(5)-Se(2) bond length is 3.03 Å. The Pr(5)-Se(3) bond length is 3.23 Å. The Pr(5)-Se(5) bond length is 3.04 Å. The Pr(5)-Se(6) bond length is 3.04 Å. The Pr(5)-Se(8) bond length is 3.21 Å. The Pr(5)-Se(9) bond length is 3.17 Å. In the sixth Pr site, Pr(6) is bonded to one Se(1), one Se(10), one Se(11), one Se(12), one Se(3), one Se(4), one Se(5), and one Se(7) atom to form distorted PrSe8 hexagonal bipyramids that share  a cornercorner with one Ca(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(2)Se8 hexagonal bipyramid,  a cornercorner with one Pr(7)Se8 hexagonal bipyramid, corners with two equivalent Pr(4)Se8 hexagonal bipyramids, corners with two equivalent Pr(8)Se8 hexagonal bipyramids,  an edgeedge with one Pr(1)Se8 hexagonal bipyramid,  an edgeedge with one Pr(7)Se8 hexagonal bipyramid, edges with two equivalent Pr(5)Se8 hexagonal bipyramids,  a faceface with one Ca(1)Se8 hexagonal bipyramid,  a faceface with one Pr(1)Se8 hexagonal bipyramid,  a faceface with one Pr(2)Se8 hexagonal bipyramid,  a faceface with one Pr(4)Se8 hexagonal bipyramid,  a faceface with one Pr(7)Se8 hexagonal bipyramid,  a faceface with one Pr(8)Se8 hexagonal bipyramid, and faces with two equivalent Pr(3)Se8 hexagonal bipyramids. The Pr(6)-Se(1) bond length is 3.01 Å. The Pr(6)-Se(10) bond length is 3.19 Å. The Pr(6)-Se(11) bond length is 3.03 Å. The Pr(6)-Se(12) bond length is 3.21 Å. The Pr(6)-Se(3) bond length is 3.02 Å. The Pr(6)-Se(4) bond length is 3.04 Å. The Pr(6)-Se(5) bond length is 3.22 Å. The Pr(6)-Se(7) bond length is 3.20 Å. In the seventh Pr site, Pr(7) is bonded to one Se(1), one Se(10), one Se(12), one Se(4), one Se(5), one Se(6), one Se(7), and one Se(8) atom to form distorted PrSe8 hexagonal bipyramids that share  a cornercorner with one Pr(1)Se8 hexagonal bipyramid,  a cornercorner with one Pr(2)Se8 hexagonal bipyramid,  a cornercorner with one Pr(5)Se8 hexagonal bipyramid,  a cornercorner with one Pr(6)Se8 hexagonal bipyramid, corners with two equivalent Pr(3)Se8 hexagonal bipyramids, corners with two equivalent Pr(4)Se8 hexagonal bipyramids,  an edgeedge with one Pr(2)Se8 hexagonal bipyramid,  an edgeedge with one Pr(6)Se8 hexagonal bipyramid, edges with two equivalent Ca(1)Se8 hexagonal bipyramids,  a faceface with one Pr(1)Se8 hexagonal bipyramid,  a faceface with one Pr(2)Se8 hexagonal bipyramid,  a faceface with one Pr(3)Se8 hexagonal bipyramid,  a faceface with one Pr(4)Se8 hexagonal bipyramid,  a faceface with one Pr(5)Se8 hexagonal bipyramid,  a faceface with one Pr(6)Se8 hexagonal bipyramid, and faces with two equivalent Pr(8)Se8 hexagonal bipyramids. The Pr(7)-Se(1) bond length is 3.04 Å. The Pr(7)-Se(10) bond length is 3.04 Å. The Pr(7)-Se(12) bond length is 3.03 Å. The Pr(7)-Se(4) bond length is 3.22 Å. The Pr(7)-Se(5) bond length is 3.22 Å. The Pr(7)-Se(6) bond length is 3.18 Å. The Pr(7)-Se(7) bond length is 3.03 Å. The Pr(7)-Se(8) bond length is 3.18 Å. In the eighth Pr site, Pr(8) is bonded to one Se(1), one Se(10), one Se(11), one Se(12), one Se(6), one Se(7), one Se(8), and one Se(9) atom to form distorted PrSe8 hexagonal bipyramids that share corners with two equivalent Pr(1)Se8 hexagonal bipyramids, corners with two equivalent Pr(2)Se8 hexagonal bipyramids, corners with two equivalent Pr(5)Se8 hexagonal bipyramids, corners with two equivalent Pr(6)Se8 hexagonal bipyramids, edges with two equivalent Pr(3)Se8 hexagonal bipyramids, edges with two equivalent Pr(4)Se8 hexagonal bipyramids,  a faceface with one Pr(1)Se8 hexagonal bipyramid,  a faceface with one Pr(2)Se8 hexagonal bipyramid,  a faceface with one Pr(5)Se8 hexagonal bipyramid,  a faceface with one Pr(6)Se8 hexagonal bipyramid, faces with two equivalent Ca(1)Se8 hexagonal bipyramids, and faces with two equivalent Pr(7)Se8 hexagonal bipyramids. The Pr(8)-Se(1) bond length is 3.21 Å. The Pr(8)-Se(10) bond length is 3.05 Å. The Pr(8)-Se(11) bond length is 3.03 Å. The Pr(8)-Se(12) bond length is 3.04 Å. The Pr(8)-Se(6) bond length is 3.19 Å. The Pr(8)-Se(7) bond length is 3.21 Å. The Pr(8)-Se(8) bond length is 3.19 Å. The Pr(8)-Se(9) bond length is 3.04 Å. There are twelve inequivalent Se sites. In the first Se site, Se(1) is bonded to one Ca(1), one Pr(1), one Pr(3), one Pr(6), one Pr(7), and one Pr(8) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(2)CaPr5 octahedra,  a cornercorner with one Se(6)CaPr5 octahedra, corners with two equivalent Se(3)CaPr5 octahedra, corners with two equivalent Se(7)CaPr5 octahedra, corners with two equivalent Se(10)Pr6 octahedra, corners with two equivalent Se(12)Pr6 octahedra, corners with two equivalent Se(4)Pr6 octahedra, corners with three equivalent Se(8)CaPr5 octahedra,  an edgeedge with one Se(11)CaPr5 octahedra,  an edgeedge with one Se(2)CaPr5 octahedra,  an edgeedge with one Se(3)CaPr5 octahedra,  an edgeedge with one Se(10)Pr6 octahedra,  an edgeedge with one Se(12)Pr6 octahedra,  an edgeedge with one Se(4)Pr6 octahedra,  a faceface with one Se(11)CaPr5 octahedra,  a faceface with one Se(6)CaPr5 octahedra,  a faceface with one Se(7)CaPr5 octahedra,  a faceface with one Se(9)CaPr5 octahedra, and  a faceface with one Se(5)Pr6 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 Pr(1), one Pr(2), one Pr(3), one Pr(4), and one Pr(5) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(1)CaPr5 octahedra,  a cornercorner with one Se(11)CaPr5 octahedra,  a cornercorner with one Se(7)CaPr5 octahedra,  a cornercorner with one Se(8)CaPr5 octahedra,  a cornercorner with one Se(10)Pr6 octahedra,  a cornercorner with one Se(4)Pr6 octahedra, corners with two equivalent Se(6)CaPr5 octahedra, corners with two equivalent Se(9)CaPr5 octahedra, corners with two equivalent Se(5)Pr6 octahedra, corners with three equivalent Se(12)Pr6 octahedra,  an edgeedge with one Se(1)CaPr5 octahedra,  an edgeedge with one Se(3)CaPr5 octahedra,  an edgeedge with one Se(6)CaPr5 octahedra,  an edgeedge with one Se(7)CaPr5 octahedra,  an edgeedge with one Se(10)Pr6 octahedra,  an edgeedge with one Se(5)Pr6 octahedra,  a faceface with one Se(11)CaPr5 octahedra,  a faceface with one Se(3)CaPr5 octahedra,  a faceface with one Se(8)CaPr5 octahedra,  a faceface with one Se(9)CaPr5 octahedra, and  a faceface with one Se(4)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 17-51°. In the third Se site, Se(3) is bonded to one Ca(1), one Pr(1), one Pr(3), one Pr(4), one Pr(5), and one Pr(6) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(8)CaPr5 octahedra,  a cornercorner with one Se(5)Pr6 octahedra, corners with two equivalent Se(1)CaPr5 octahedra, corners with two equivalent Se(11)CaPr5 octahedra, corners with two equivalent Se(7)CaPr5 octahedra, corners with two equivalent Se(9)CaPr5 octahedra, corners with two equivalent Se(4)Pr6 octahedra, corners with three equivalent Se(10)Pr6 octahedra,  an edgeedge with one Se(1)CaPr5 octahedra,  an edgeedge with one Se(2)CaPr5 octahedra,  an edgeedge with one Se(7)CaPr5 octahedra,  an edgeedge with one Se(8)CaPr5 octahedra,  an edgeedge with one Se(9)CaPr5 octahedra,  an edgeedge with one Se(4)Pr6 octahedra,  a faceface with one Se(11)CaPr5 octahedra,  a faceface with one Se(2)CaPr5 octahedra,  a faceface with one Se(6)CaPr5 octahedra,  a faceface with one Se(12)Pr6 octahedra, and  a faceface with one Se(5)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the fourth Se site, Se(4) is bonded to one Pr(1), one Pr(2), one Pr(3), one Pr(4), one Pr(6), and one Pr(7) atom to form distorted SePr6 octahedra that share  a cornercorner with one Se(11)CaPr5 octahedra,  a cornercorner with one Se(2)CaPr5 octahedra,  a cornercorner with one Se(6)CaPr5 octahedra,  a cornercorner with one Se(7)CaPr5 octahedra,  a cornercorner with one Se(8)CaPr5 octahedra,  a cornercorner with one Se(10)Pr6 octahedra, corners with two equivalent Se(1)CaPr5 octahedra, corners with two equivalent Se(3)CaPr5 octahedra, corners with two equivalent Se(12)Pr6 octahedra, corners with three equivalent Se(9)CaPr5 octahedra,  an edgeedge with one Se(1)CaPr5 octahedra,  an edgeedge with one Se(11)CaPr5 octahedra,  an edgeedge with one Se(3)CaPr5 octahedra,  an edgeedge with one Se(6)CaPr5 octahedra,  an edgeedge with one Se(8)CaPr5 octahedra,  an edgeedge with one Se(5)Pr6 octahedra,  a faceface with one Se(2)CaPr5 octahedra,  a faceface with one Se(7)CaPr5 octahedra,  a faceface with one Se(10)Pr6 octahedra,  a faceface with one Se(12)Pr6 octahedra, and  a faceface with one Se(5)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the fifth Se site, Se(5) is bonded to one Pr(2), one Pr(3), one Pr(4), one Pr(5), one Pr(6), and one Pr(7) atom to form distorted SePr6 octahedra that share  a cornercorner with one Se(3)CaPr5 octahedra,  a cornercorner with one Se(7)CaPr5 octahedra, corners with two equivalent Se(2)CaPr5 octahedra, corners with two equivalent Se(6)CaPr5 octahedra, corners with two equivalent Se(8)CaPr5 octahedra, corners with two equivalent Se(10)Pr6 octahedra, corners with two equivalent Se(12)Pr6 octahedra, corners with three equivalent Se(11)CaPr5 octahedra,  an edgeedge with one Se(2)CaPr5 octahedra,  an edgeedge with one Se(6)CaPr5 octahedra,  an edgeedge with one Se(7)CaPr5 octahedra,  an edgeedge with one Se(8)CaPr5 octahedra,  an edgeedge with one Se(12)Pr6 octahedra,  an edgeedge with one Se(4)Pr6 octahedra,  a faceface with one Se(1)CaPr5 octahedra,  a faceface with one Se(3)CaPr5 octahedra,  a faceface with one Se(9)CaPr5 octahedra,  a faceface with one Se(10)Pr6 octahedra, and  a faceface with one Se(4)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 16-51°. In the sixth Se site, Se(6) is bonded to one Ca(1), one Pr(2), one Pr(3), one Pr(5), one Pr(7), and one Pr(8) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(1)CaPr5 octahedra,  a cornercorner with one Se(4)Pr6 octahedra, corners with two equivalent Se(11)CaPr5 octahedra, corners with two equivalent Se(2)CaPr5 octahedra, corners with two equivalent Se(8)CaPr5 octahedra, corners with two equivalent Se(9)CaPr5 octahedra, corners with two equivalent Se(5)Pr6 octahedra, corners with three equivalent Se(7)CaPr5 octahedra,  an edgeedge with one Se(11)CaPr5 octahedra,  an edgeedge with one Se(2)CaPr5 octahedra,  an edgeedge with one Se(9)CaPr5 octahedra,  an edgeedge with one Se(10)Pr6 octahedra,  an edgeedge with one Se(4)Pr6 octahedra,  an edgeedge with one Se(5)Pr6 octahedra,  a faceface with one Se(1)CaPr5 octahedra,  a faceface with one Se(3)CaPr5 octahedra,  a faceface with one Se(8)CaPr5 octahedra,  a faceface with one Se(10)Pr6 octahedra, and  a faceface with one Se(12)Pr6 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 Pr(1), one Pr(4), one Pr(6), one Pr(7), and one Pr(8) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(11)CaPr5 octahedra,  a cornercorner with one Se(2)CaPr5 octahedra,  a cornercorner with one Se(8)CaPr5 octahedra,  a cornercorner with one Se(10)Pr6 octahedra,  a cornercorner with one Se(4)Pr6 octahedra,  a cornercorner with one Se(5)Pr6 octahedra, corners with two equivalent Se(1)CaPr5 octahedra, corners with two equivalent Se(3)CaPr5 octahedra, corners with two equivalent Se(9)CaPr5 octahedra, corners with three equivalent Se(6)CaPr5 octahedra,  an edgeedge with one Se(2)CaPr5 octahedra,  an edgeedge with one Se(3)CaPr5 octahedra,  an edgeedge with one Se(9)CaPr5 octahedra,  an edgeedge with one Se(10)Pr6 octahedra,  an edgeedge with one Se(12)Pr6 octahedra,  an edgeedge with one Se(5)Pr6 octahedra,  a faceface with one Se(1)CaPr5 octahedra,  a faceface with one Se(11)CaPr5 octahedra,  a faceface with one Se(8)CaPr5 octahedra,  a faceface with one Se(12)Pr6 octahedra, and  a faceface with one Se(4)Pr6 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 Pr(2), one Pr(4), one Pr(5), one Pr(7), and one Pr(8) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(11)CaPr5 octahedra,  a cornercorner with one Se(2)CaPr5 octahedra,  a cornercorner with one Se(3)CaPr5 octahedra,  a cornercorner with one Se(7)CaPr5 octahedra,  a cornercorner with one Se(10)Pr6 octahedra,  a cornercorner with one Se(4)Pr6 octahedra, corners with two equivalent Se(6)CaPr5 octahedra, corners with two equivalent Se(12)Pr6 octahedra, corners with two equivalent Se(5)Pr6 octahedra, corners with three equivalent Se(1)CaPr5 octahedra,  an edgeedge with one Se(11)CaPr5 octahedra,  an edgeedge with one Se(3)CaPr5 octahedra,  an edgeedge with one Se(9)CaPr5 octahedra,  an edgeedge with one Se(12)Pr6 octahedra,  an edgeedge with one Se(4)Pr6 octahedra,  an edgeedge with one Se(5)Pr6 octahedra,  a faceface with one Se(2)CaPr5 octahedra,  a faceface with one Se(6)CaPr5 octahedra,  a faceface with one Se(7)CaPr5 octahedra,  a faceface with one Se(9)CaPr5 octahedra, and  a faceface with one Se(10)Pr6 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 Pr(1), one Pr(2), one Pr(4), one Pr(5), and one Pr(8) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(10)Pr6 octahedra,  a cornercorner with one Se(12)Pr6 octahedra, corners with two equivalent Se(11)CaPr5 octahedra, corners with two equivalent Se(2)CaPr5 octahedra, corners with two equivalent Se(3)CaPr5 octahedra, corners with two equivalent Se(6)CaPr5 octahedra, corners with two equivalent Se(7)CaPr5 octahedra, corners with three equivalent Se(4)Pr6 octahedra,  an edgeedge with one Se(11)CaPr5 octahedra,  an edgeedge with one Se(3)CaPr5 octahedra,  an edgeedge with one Se(6)CaPr5 octahedra,  an edgeedge with one Se(7)CaPr5 octahedra,  an edgeedge with one Se(8)CaPr5 octahedra,  an edgeedge with one Se(10)Pr6 octahedra,  a faceface with one Se(1)CaPr5 octahedra,  a faceface with one Se(2)CaPr5 octahedra,  a faceface with one Se(8)CaPr5 octahedra,  a faceface with one Se(12)Pr6 octahedra, and  a faceface with one Se(5)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 17-50°. In the tenth Se site, Se(10) is bonded to one Pr(2), one Pr(3), one Pr(5), one Pr(6), one Pr(7), and one Pr(8) atom to form distorted SePr6 octahedra that share  a cornercorner with one Se(11)CaPr5 octahedra,  a cornercorner with one Se(2)CaPr5 octahedra,  a cornercorner with one Se(7)CaPr5 octahedra,  a cornercorner with one Se(8)CaPr5 octahedra,  a cornercorner with one Se(9)CaPr5 octahedra,  a cornercorner with one Se(4)Pr6 octahedra, corners with two equivalent Se(1)CaPr5 octahedra, corners with two equivalent Se(12)Pr6 octahedra, corners with two equivalent Se(5)Pr6 octahedra, corners with three equivalent Se(3)CaPr5 octahedra,  an edgeedge with one Se(1)CaPr5 octahedra,  an edgeedge with one Se(2)CaPr5 octahedra,  an edgeedge with one Se(6)CaPr5 octahedra,  an edgeedge with one Se(7)CaPr5 octahedra,  an edgeedge with one Se(9)CaPr5 octahedra,  an edgeedge with one Se(12)Pr6 octahedra,  a faceface with one Se(11)CaPr5 octahedra,  a faceface with one Se(6)CaPr5 octahedra,  a faceface with one Se(8)CaPr5 octahedra,  a faceface with one Se(4)Pr6 octahedra, and  a faceface with one Se(5)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 16-50°. In the eleventh Se site, Se(11) is bonded to one Ca(1), one Pr(1), one Pr(3), one Pr(5), one Pr(6), and one Pr(8) atom to form distorted SeCaPr5 octahedra that share  a cornercorner with one Se(2)CaPr5 octahedra,  a cornercorner with one Se(7)CaPr5 octahedra,  a cornercorner with one Se(8)CaPr5 octahedra,  a cornercorner with one Se(10)Pr6 octahedra,  a cornercorner with one Se(12)Pr6 octahedra,  a cornercorner with one Se(4)Pr6 octahedra, corners with two equivalent Se(3)CaPr5 octahedra, corners with two equivalent Se(6)CaPr5 octahedra, corners with two equivalent Se(9)CaPr5 octahedra, corners with three equivalent Se(5)Pr6 octahedra,  an edgeedge with one Se(1)CaPr5 octahedra,  an edgeedge with one Se(6)CaPr5 octahedra,  an edgeedge with one Se(8)CaPr5 octahedra,  an edgeedge with one Se(9)CaPr5 octahedra,  an edgeedge with one Se(12)Pr6 octahedra,  an edgeedge with one Se(4)Pr6 octahedra,  a faceface with one Se(1)CaPr5 octahedra,  a faceface with one Se(2)CaPr5 octahedra,  a faceface with one Se(3)CaPr5 octahedra,  a faceface with one Se(7)CaPr5 octahedra, and  a faceface with one Se(10)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 17-51°. In the twelfth Se site, Se(12) is bonded to one Pr(1), one Pr(2), one Pr(4), one Pr(6), one Pr(7), and one Pr(8) atom to form distorted SePr6 octahedra that share  a cornercorner with one Se(11)CaPr5 octahedra,  a cornercorner with one Se(9)CaPr5 octahedra, corners with two equivalent Se(1)CaPr5 octahedra, corners with two equivalent Se(8)CaPr5 octahedra, corners with two equivalent Se(10)Pr6 octahedra, corners with two equivalent Se(4)Pr6 octahedra, corners with two equivalent Se(5)Pr6 octahedra, corners with three equivalent Se(2)CaPr5 octahedra,  an edgeedge with one Se(1)CaPr5 octahedra,  an edgeedge with one Se(11)CaPr5 octahedra,  an edgeedge with one Se(7)CaPr5 octahedra,  an edgeedge with one Se(8)CaPr5 octahedra,  an edgeedge with one Se(10)Pr6 octahedra,  an edgeedge with one Se(5)Pr6 octahedra,  a faceface with one Se(3)CaPr5 octahedra,  a faceface with one Se(6)CaPr5 octahedra,  a faceface with one Se(7)CaPr5 octahedra,  a faceface with one Se(9)CaPr5 octahedra, and  a faceface with one Se(4)Pr6 octahedra. The corner-sharing octahedral tilt angles range from 16-51°.