Pr7FeI12 is trigonal omega-derived structured and crystallizes in the trigonal R-3 space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one Fe(1), two equivalent I(2), and three equivalent I(1) atoms to form distorted PrFeI5 octahedra that share corners with three equivalent Pr(1)FeI5 octahedra,  an edgeedge with one Pr(2)I6 octahedra, and edges with five equivalent Pr(1)FeI5 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the second Pr site, Pr(2) is bonded to six equivalent I(2) atoms to form edge-sharing PrI6 octahedra. Fe(1) is bonded in an octahedral geometry to six equivalent Pr(1) atoms. There are two inequivalent I sites. In the first I site, I(1) is bonded in a distorted T-shaped geometry to three equivalent Pr(1) atoms. In the second I site, I(2) is bonded in a distorted T-shaped geometry to one Pr(2) and two equivalent Pr(1) atoms.
Pr7FeI12 is trigonal omega-derived structured and crystallizes in the trigonal R-3 space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to one Fe(1), two equivalent I(2), and three equivalent I(1) atoms to form distorted PrFeI5 octahedra that share corners with three equivalent Pr(1)FeI5 octahedra,  an edgeedge with one Pr(2)I6 octahedra, and edges with five equivalent Pr(1)FeI5 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. The Pr(1)-Fe(1) bond length is 2.77 Å. Both Pr(1)-I(2) bond lengths are 3.30 Å. There are a spread of Pr(1)-I(1) bond distances ranging from 3.21-3.51 Å. In the second Pr site, Pr(2) is bonded to six equivalent I(2) atoms to form edge-sharing PrI6 octahedra. All Pr(2)-I(2) bond lengths are 3.18 Å. Fe(1) is bonded in an octahedral geometry to six equivalent Pr(1) atoms. There are two inequivalent I sites. In the first I site, I(1) is bonded in a distorted T-shaped geometry to three equivalent Pr(1) atoms. In the second I site, I(2) is bonded in a distorted T-shaped geometry to one Pr(2) and two equivalent Pr(1) atoms.