DOE OSTI2020
Pr3CBr5 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are three inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded to two equivalent C4- and five Br1- atoms to form distorted PrC2Br5 pentagonal bipyramids that share a cornercorner with one PrCBr5 octahedra, corners with two equivalent PrC2Br5 pentagonal bipyramids, edges with three equivalent PrCBr5 octahedra, edges with two equivalent PrC2Br5 pentagonal bipyramids, and faces with two equivalent PrC2Br5 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 5°. There are one shorter (2.62 Å) and one longer (2.64 Å) Pr–C bond lengths. There are a spread of Pr–Br bond distances ranging from 2.97–3.23 Å. In the second Pr3+ site, Pr3+ is bonded to two equivalent C4- and five Br1- atoms to form PrC2Br5 pentagonal bipyramids that share corners with two equivalent PrC2Br5 pentagonal bipyramids, edges with three equivalent PrCBr5 octahedra, edges with two equivalent PrC2Br5 pentagonal bipyramids, and faces with two equivalent PrC2Br5 pentagonal bipyramids. There are one shorter (2.63 Å) and one longer (2.65 Å) Pr–C bond lengths. There are three shorter (2.97 Å) and two longer (3.22 Å) Pr–Br bond lengths. In the third Pr3+ site, Pr3+ is bonded to one C4- and five Br1- atoms to form PrCBr5 octahedra that share a cornercorner with one PrC2Br5 pentagonal bipyramid, an edgeedge with one PrCBr5 octahedra, and edges with six PrC2Br5 pentagonal bipyramids. The Pr–C bond length is 2.33 Å. There are a spread of Pr–Br bond distances ranging from 2.90–3.20 Å. C4- is bonded in a 6-coordinate geometry to five Pr3+ and one C4- atom. The C–C bond length is 1.41 Å. There are five inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a distorted T-shaped geometry to three Pr3+ atoms. In the second Br1- site, Br1- is bonded in a distorted see-saw-like geometry to four Pr3+ atoms. In the third Br1- site, Br1- is bonded in a 3-coordinate geometry to three Pr3+ atoms. In the fourth Br1- site, Br1- is bonded in a distorted T-shaped geometry to three Pr3+ atoms. In the fifth Br1- site, Br1- is bonded in an L-shaped geometry to two Pr3+ atoms.