Pr3I3Os crystallizes in the monoclinic P2_1/m space group. There are three inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to two equivalent Os(1), one I(3), and three equivalent I(1) atoms to form distorted PrOs2I4 octahedra that share corners with four equivalent Pr(3)Os3I3 octahedra, edges with four equivalent Pr(1)Os2I4 octahedra, and edges with four equivalent Pr(3)Os3I3 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. In the second Pr site, Pr(2) is bonded in a 6-coordinate geometry to one Os(1), two equivalent I(3), and three equivalent I(2) atoms. In the third Pr site, Pr(3) is bonded to three equivalent Os(1), one I(2), and two equivalent I(1) atoms to form PrOs3I3 octahedra that share corners with four equivalent Pr(1)Os2I4 octahedra, edges with four equivalent Pr(1)Os2I4 octahedra, and edges with four equivalent Pr(3)Os3I3 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. Os(1) is bonded to one Pr(2), two equivalent Pr(1), and three equivalent Pr(3) atoms to form OsPr6 octahedra that share corners with four equivalent I(1)Pr5 trigonal bipyramids, edges with four equivalent Os(1)Pr6 octahedra, and edges with four equivalent I(1)Pr5 trigonal bipyramids. There are three inequivalent I sites. In the first I site, I(1) is bonded to two equivalent Pr(3) and three equivalent Pr(1) atoms to form distorted IPr5 trigonal bipyramids that share corners with four equivalent Os(1)Pr6 octahedra, edges with four equivalent Os(1)Pr6 octahedra, and edges with four equivalent I(1)Pr5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 12-13°. In the second I site, I(2) is bonded in a distorted see-saw-like geometry to one Pr(3) and three equivalent Pr(2) atoms. In the third I site, I(3) is bonded in a distorted T-shaped geometry to one Pr(1) and two equivalent Pr(2) atoms.
Pr3I3Os crystallizes in the monoclinic P2_1/m space group. There are three inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to two equivalent Os(1), one I(3), and three equivalent I(1) atoms to form distorted PrOs2I4 octahedra that share corners with four equivalent Pr(3)Os3I3 octahedra, edges with four equivalent Pr(1)Os2I4 octahedra, and edges with four equivalent Pr(3)Os3I3 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. Both Pr(1)-Os(1) bond lengths are 2.86 Å. The Pr(1)-I(3) bond length is 3.28 Å. There is one shorter (3.33 Å) and two longer (3.52 Å) Pr(1)-I(1) bond lengths. In the second Pr site, Pr(2) is bonded in a 6-coordinate geometry to one Os(1), two equivalent I(3), and three equivalent I(2) atoms. The Pr(2)-Os(1) bond length is 2.67 Å. Both Pr(2)-I(3) bond lengths are 3.23 Å. There are two shorter (3.28 Å) and one longer (3.62 Å) Pr(2)-I(2) bond length. In the third Pr site, Pr(3) is bonded to three equivalent Os(1), one I(2), and two equivalent I(1) atoms to form PrOs3I3 octahedra that share corners with four equivalent Pr(1)Os2I4 octahedra, edges with four equivalent Pr(1)Os2I4 octahedra, and edges with four equivalent Pr(3)Os3I3 octahedra. The corner-sharing octahedral tilt angles range from 3-8°. There are two shorter (2.91 Å) and one longer (2.92 Å) Pr(3)-Os(1) bond length. The Pr(3)-I(2) bond length is 3.48 Å. Both Pr(3)-I(1) bond lengths are 3.57 Å. Os(1) is bonded to one Pr(2), two equivalent Pr(1), and three equivalent Pr(3) atoms to form OsPr6 octahedra that share corners with four equivalent I(1)Pr5 trigonal bipyramids, edges with four equivalent Os(1)Pr6 octahedra, and edges with four equivalent I(1)Pr5 trigonal bipyramids. There are three inequivalent I sites. In the first I site, I(1) is bonded to two equivalent Pr(3) and three equivalent Pr(1) atoms to form distorted IPr5 trigonal bipyramids that share corners with four equivalent Os(1)Pr6 octahedra, edges with four equivalent Os(1)Pr6 octahedra, and edges with four equivalent I(1)Pr5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 12-13°. In the second I site, I(2) is bonded in a distorted see-saw-like geometry to one Pr(3) and three equivalent Pr(2) atoms. In the third I site, I(3) is bonded in a distorted T-shaped geometry to one Pr(1) and two equivalent Pr(2) atoms.