DOE OSTI2020
ThI6PbI6 crystallizes in the monoclinic Pm space group. The structure is two-dimensional and consists of one PbI6 sheet oriented in the (0, 0, 1) direction and one ThI6 sheet oriented in the (0, 0, 1) direction. In the PbI6 sheet, Pb2+ is bonded in a 8-coordinate geometry to eight I+0.50- atoms. There are a spread of Pb–I bond distances ranging from 3.04–3.93 Å. There are four inequivalent I+0.50- sites. In the first I+0.50- site, I+0.50- is bonded in a 4-coordinate geometry to two equivalent Pb2+ and two I+0.50- atoms. There are one shorter (2.96 Å) and one longer (3.33 Å) I–I bond lengths. In the second I+0.50- site, I+0.50- is bonded in a 2-coordinate geometry to two equivalent Pb2+ and two equivalent I+0.50- atoms. Both I–I bond lengths are 3.47 Å. In the third I+0.50- site, I+0.50- is bonded in a linear geometry to two equivalent I+0.50- atoms. In the fourth I+0.50- site, I+0.50- is bonded in a 1-coordinate geometry to one Pb2+ and two I+0.50- atoms. The I–I bond length is 2.78 Å. In the ThI6 sheet, Th4+ is bonded in a 8-coordinate geometry to eight I+0.50- atoms. There are a spread of Th–I bond distances ranging from 2.96–3.56 Å. There are four inequivalent I+0.50- sites. In the first I+0.50- site, I+0.50- is bonded in a single-bond geometry to one Th4+ atom. In the second I+0.50- site, I+0.50- is bonded in a distorted linear geometry to two equivalent I+0.50- atoms. Both I–I bond lengths are 3.01 Å. In the third I+0.50- site, I+0.50- is bonded in a water-like geometry to two equivalent Th4+ atoms. In the fourth I+0.50- site, I+0.50- is bonded in a 2-coordinate geometry to two equivalent Th4+ and two I+0.50- atoms. The I–I bond length is 3.23 Å.