Pr4I5Ni crystallizes in the orthorhombic Pmmn space group. There are three inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one Ni(1), two equivalent I(1), and three equivalent I(2) atoms to form distorted PrNiI5 octahedra that share  a cornercorner with one Pr(2)Ni2I4 octahedra,  a cornercorner with one Pr(1)NiI5 octahedra, edges with two equivalent Pr(2)Ni2I4 octahedra, edges with two equivalent Pr(3)Ni2I4 octahedra, and edges with four equivalent Pr(1)NiI5 octahedra. The corner-sharing octahedral tilt angles range from 2-10°. In the second Pr site, Pr(2) is bonded to two equivalent Ni(1), two equivalent I(2), and two equivalent I(3) atoms to form PrNi2I4 octahedra that share corners with two equivalent Pr(1)NiI5 octahedra, corners with four equivalent Pr(3)Ni2I4 octahedra, edges with two equivalent Pr(2)Ni2I4 octahedra, edges with two equivalent Pr(3)Ni2I4 octahedra, and edges with four equivalent Pr(1)NiI5 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. In the third Pr site, Pr(3) is bonded to two equivalent Ni(1), two equivalent I(1), and two equivalent I(3) atoms to form PrNi2I4 octahedra that share corners with four equivalent Pr(2)Ni2I4 octahedra, edges with two equivalent Pr(2)Ni2I4 octahedra, edges with two equivalent Pr(3)Ni2I4 octahedra, and edges with four equivalent Pr(1)NiI5 octahedra. The corner-sharing octahedra are not tilted. Ni(1) is bonded to two equivalent Pr(1), two equivalent Pr(2), and two equivalent Pr(3) atoms to form edge-sharing NiPr6 octahedra. There are three inequivalent I sites. In the first I site, I(1) is bonded in a 3-coordinate geometry to one Pr(3) and two equivalent Pr(1) atoms. In the second I site, I(2) is bonded in a distorted see-saw-like geometry to one Pr(2) and three equivalent Pr(1) atoms. In the third I site, I(3) is bonded in a square co-planar geometry to two equivalent Pr(2) and two equivalent Pr(3) atoms.
Pr4I5Ni crystallizes in the orthorhombic Pmmn space group. There are three inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one Ni(1), two equivalent I(1), and three equivalent I(2) atoms to form distorted PrNiI5 octahedra that share  a cornercorner with one Pr(2)Ni2I4 octahedra,  a cornercorner with one Pr(1)NiI5 octahedra, edges with two equivalent Pr(2)Ni2I4 octahedra, edges with two equivalent Pr(3)Ni2I4 octahedra, and edges with four equivalent Pr(1)NiI5 octahedra. The corner-sharing octahedral tilt angles range from 2-10°. The Pr(1)-Ni(1) bond length is 2.79 Å. Both Pr(1)-I(1) bond lengths are 3.23 Å. There are two shorter (3.28 Å) and one longer (3.48 Å) Pr(1)-I(2) bond length. In the second Pr site, Pr(2) is bonded to two equivalent Ni(1), two equivalent I(2), and two equivalent I(3) atoms to form PrNi2I4 octahedra that share corners with two equivalent Pr(1)NiI5 octahedra, corners with four equivalent Pr(3)Ni2I4 octahedra, edges with two equivalent Pr(2)Ni2I4 octahedra, edges with two equivalent Pr(3)Ni2I4 octahedra, and edges with four equivalent Pr(1)NiI5 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. Both Pr(2)-Ni(1) bond lengths are 2.83 Å. Both Pr(2)-I(2) bond lengths are 3.38 Å. Both Pr(2)-I(3) bond lengths are 3.40 Å. In the third Pr site, Pr(3) is bonded to two equivalent Ni(1), two equivalent I(1), and two equivalent I(3) atoms to form PrNi2I4 octahedra that share corners with four equivalent Pr(2)Ni2I4 octahedra, edges with two equivalent Pr(2)Ni2I4 octahedra, edges with two equivalent Pr(3)Ni2I4 octahedra, and edges with four equivalent Pr(1)NiI5 octahedra. The corner-sharing octahedra are not tilted. Both Pr(3)-Ni(1) bond lengths are 2.85 Å. Both Pr(3)-I(1) bond lengths are 3.29 Å. Both Pr(3)-I(3) bond lengths are 3.42 Å. Ni(1) is bonded to two equivalent Pr(1), two equivalent Pr(2), and two equivalent Pr(3) atoms to form edge-sharing NiPr6 octahedra. There are three inequivalent I sites. In the first I site, I(1) is bonded in a 3-coordinate geometry to one Pr(3) and two equivalent Pr(1) atoms. In the second I site, I(2) is bonded in a distorted see-saw-like geometry to one Pr(2) and three equivalent Pr(1) atoms. In the third I site, I(3) is bonded in a square co-planar geometry to two equivalent Pr(2) and two equivalent Pr(3) atoms.