Cs4Pr6OsI13 crystallizes in the monoclinic C2/m space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 9-coordinate geometry to one I(4), two equivalent I(1), two equivalent I(2), and four equivalent I(5) atoms. In the second Cs site, Cs(2) is bonded in a 6-coordinate geometry to one I(2), one I(4), two equivalent I(1), two equivalent I(3), and two equivalent I(5) atoms. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one Os(1), one I(4), two equivalent I(1), and two equivalent I(5) atoms to form a mixture of distorted corner and edge-sharing PrOsI5 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the second Pr site, Pr(2) is bonded to one Os(1), one I(2), one I(3), one I(5), and two equivalent I(1) atoms to form a mixture of corner and edge-sharing PrOsI5 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. Os(1) is bonded to two equivalent Pr(1) and four equivalent Pr(2) atoms to form OsPr6 octahedra that share corners with two equivalent I(4)Cs4Pr2 octahedra, corners with four equivalent I(1)Cs2Pr3 trigonal bipyramids, and edges with four equivalent I(1)Cs2Pr3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 5°. There are five inequivalent I sites. In the first I site, I(1) is bonded to one Cs(1), one Cs(2), one Pr(1), and two equivalent Pr(2) atoms to form distorted ICs2Pr3 trigonal bipyramids that share  a cornercorner with one Os(1)Pr6 octahedra,  a cornercorner with one I(1)Cs2Pr3 trigonal bipyramid,  an edgeedge with one Os(1)Pr6 octahedra, edges with two equivalent I(1)Cs2Pr3 trigonal bipyramids, and  a faceface with one I(4)Cs4Pr2 octahedra. The corner-sharing octahedral tilt angles are 5°. In the second I site, I(2) is bonded in a 5-coordinate geometry to one Cs(2), two equivalent Cs(1), and two equivalent Pr(2) atoms. In the third I site, I(3) is bonded in a 4-coordinate geometry to two equivalent Cs(2) and two equivalent Pr(2) atoms. In the fourth I site, I(4) is bonded to two equivalent Cs(1), two equivalent Cs(2), and two equivalent Pr(1) atoms to form ICs4Pr2 octahedra that share corners with two equivalent Os(1)Pr6 octahedra and faces with four equivalent I(1)Cs2Pr3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 5°. In the fifth I site, I(5) is bonded in a 5-coordinate geometry to one Cs(2), two equivalent Cs(1), one Pr(1), and one Pr(2) atom.
Cs4Pr6OsI13 crystallizes in the monoclinic C2/m space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 9-coordinate geometry to one I(4), two equivalent I(1), two equivalent I(2), and four equivalent I(5) atoms. The Cs(1)-I(4) bond length is 3.98 Å. Both Cs(1)-I(1) bond lengths are 3.96 Å. Both Cs(1)-I(2) bond lengths are 4.33 Å. There are two shorter (4.06 Å) and two longer (4.30 Å) Cs(1)-I(5) bond lengths. In the second Cs site, Cs(2) is bonded in a 6-coordinate geometry to one I(2), one I(4), two equivalent I(1), two equivalent I(3), and two equivalent I(5) atoms. The Cs(2)-I(2) bond length is 4.22 Å. The Cs(2)-I(4) bond length is 4.13 Å. Both Cs(2)-I(1) bond lengths are 4.01 Å. Both Cs(2)-I(3) bond lengths are 4.03 Å. Both Cs(2)-I(5) bond lengths are 4.54 Å. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one Os(1), one I(4), two equivalent I(1), and two equivalent I(5) atoms to form a mixture of distorted corner and edge-sharing PrOsI5 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. The Pr(1)-Os(1) bond length is 2.74 Å. The Pr(1)-I(4) bond length is 3.54 Å. Both Pr(1)-I(1) bond lengths are 3.29 Å. Both Pr(1)-I(5) bond lengths are 3.24 Å. In the second Pr site, Pr(2) is bonded to one Os(1), one I(2), one I(3), one I(5), and two equivalent I(1) atoms to form a mixture of corner and edge-sharing PrOsI5 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. The Pr(2)-Os(1) bond length is 2.85 Å. The Pr(2)-I(2) bond length is 3.31 Å. The Pr(2)-I(3) bond length is 3.24 Å. The Pr(2)-I(5) bond length is 3.25 Å. There is one shorter (3.28 Å) and one longer (3.48 Å) Pr(2)-I(1) bond length. Os(1) is bonded to two equivalent Pr(1) and four equivalent Pr(2) atoms to form OsPr6 octahedra that share corners with two equivalent I(4)Cs4Pr2 octahedra, corners with four equivalent I(1)Cs2Pr3 trigonal bipyramids, and edges with four equivalent I(1)Cs2Pr3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 5°. There are five inequivalent I sites. In the first I site, I(1) is bonded to one Cs(1), one Cs(2), one Pr(1), and two equivalent Pr(2) atoms to form distorted ICs2Pr3 trigonal bipyramids that share  a cornercorner with one Os(1)Pr6 octahedra,  a cornercorner with one I(1)Cs2Pr3 trigonal bipyramid,  an edgeedge with one Os(1)Pr6 octahedra, edges with two equivalent I(1)Cs2Pr3 trigonal bipyramids, and  a faceface with one I(4)Cs4Pr2 octahedra. The corner-sharing octahedral tilt angles are 5°. In the second I site, I(2) is bonded in a 5-coordinate geometry to one Cs(2), two equivalent Cs(1), and two equivalent Pr(2) atoms. In the third I site, I(3) is bonded in a 4-coordinate geometry to two equivalent Cs(2) and two equivalent Pr(2) atoms. In the fourth I site, I(4) is bonded to two equivalent Cs(1), two equivalent Cs(2), and two equivalent Pr(1) atoms to form ICs4Pr2 octahedra that share corners with two equivalent Os(1)Pr6 octahedra and faces with four equivalent I(1)Cs2Pr3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 5°. In the fifth I site, I(5) is bonded in a 5-coordinate geometry to one Cs(2), two equivalent Cs(1), one Pr(1), and one Pr(2) atom.