Synthesen, Eigenschaften und Kristallstrukturen der Cluster‐Salze Bi 6 [PtBi 6 Cl 12 ] und Bi 2/3 [PtBi 6 Cl 12 ]

Syntheses, Properties and Crystal Structures of the Cluster Salts Bi 6 [PtBi 6 Cl 12 ] and Bi 2/3 [PtBi 6 Cl 12 ] Melting reactions of Bi with Pt and BiCl 3 yield shiny black, air insensitive crystals of the subchlorides Bi 6 [PtBi 6 Cl 12 ] and Bi 2/3 [PtBi 6 Cl 12 ]. Despite the substantial difference in the bismuth content the two compounds have almost the same pseudo‐cubic unit cell and follow the structural principle of a CsCl type cluster salt. Bi 6 [PtBi 6 Cl 12 ] consists of cuboctahedral [PtBi 6 Cl 12 ] 2− clusters and Bi 6 2+ polycations ( a = 9.052(2) Å, α = 89.88(2)°, space group P 1, multiple twins). In the electron precise cluster anion, the Pt atom (18 electron count) centers an octahedron of Bi atoms whose edges are bridged by chlorine atoms. The Bi 6 2+ cation, a nido cluster with 16 skeletal electrons, has the shape of a distorted octahedron with an opened edge. In Bi 2/3 [PtBi 6 Cl 12 ] the anion charge is compensated by weakly coordinating Bi 3+ cations which are distributed statistically over two crystallographic positions ( a = 9.048(2) Å, α = 90.44(3)°, space group $R{\bar 3}$ ). Bi 6 [PtBi 6 Cl 12 ] is a semiconductor with a band gap of about 0.1 eV. The compound is diamagnetic at room temperature though a small paramagnetic contribution appears towards lower temperature.