Pt3I8 crystallizes in the tetragonal P4_32_12 space group. There are two inequivalent Pt sites. In the first Pt site, Pt(1) is bonded to one I(2), one I(4), two equivalent I(1), and two equivalent I(3) atoms to form a mixture of corner and edge-sharing PtI6 octahedra. The corner-sharing octahedral tilt angles range from 4-12°. In the second Pt site, Pt(2) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(4) atoms to form a mixture of corner and edge-sharing PtI6 octahedra. The corner-sharing octahedral tilt angles range from 4-12°. There are four inequivalent I sites. In the first I site, I(4) is bonded in an L-shaped geometry to one Pt(1) and one Pt(2) atom. In the second I site, I(1) is bonded in a T-shaped geometry to one Pt(2) and two equivalent Pt(1) atoms. In the third I site, I(2) is bonded in a distorted linear geometry to one Pt(1) and one Pt(2) atom. In the fourth I site, I(3) is bonded in a water-like geometry to two equivalent Pt(1) atoms.
Pt3I8 crystallizes in the tetragonal P4_32_12 space group. There are two inequivalent Pt sites. In the first Pt site, Pt(1) is bonded to one I(2), one I(4), two equivalent I(1), and two equivalent I(3) atoms to form a mixture of corner and edge-sharing PtI6 octahedra. The corner-sharing octahedral tilt angles range from 4-12°. The Pt(1)-I(2) bond length is 3.35 Å. The Pt(1)-I(4) bond length is 2.65 Å. There is one shorter (2.62 Å) and one longer (3.20 Å) Pt(1)-I(1) bond length. Both Pt(1)-I(3) bond lengths are 2.66 Å. In the second Pt site, Pt(2) is bonded to two equivalent I(1), two equivalent I(2), and two equivalent I(4) atoms to form a mixture of corner and edge-sharing PtI6 octahedra. The corner-sharing octahedral tilt angles range from 4-12°. Both Pt(2)-I(1) bond lengths are 2.75 Å. Both Pt(2)-I(2) bond lengths are 2.74 Å. Both Pt(2)-I(4) bond lengths are 2.68 Å. There are four inequivalent I sites. In the first I site, I(4) is bonded in an L-shaped geometry to one Pt(1) and one Pt(2) atom. In the second I site, I(1) is bonded in a T-shaped geometry to one Pt(2) and two equivalent Pt(1) atoms. In the third I site, I(2) is bonded in a distorted linear geometry to one Pt(1) and one Pt(2) atom. In the fourth I site, I(3) is bonded in a water-like geometry to two equivalent Pt(1) atoms.