The Bicyclic Polyselenium Cation Se102+ in the Structure of Se10[Bi4Cl14]

In the ternary system Se/Bi/Cl a new polycation containing phase besides the already known Se₄Bi₄Cl₁₄], Se₈Bi₄Cl₁₄], and Se₁₀Bi₅Cl₁₇] was discovered. Red, transparent, plate shaped crystals of Se₁₀Bi₄Cl₁₄] were formed by reaction of Se/SeCl₄/BiCl₃ in 15:1:8 molar ratio in evacuated glass ampoules applying a temperature gradient from 90 to 80 °C. The crystal structure consists of bicyclic Se₁₀²⁺ cations and of layered chloridobismutate anions with the cations located between the anionic planes. The atoms of the cation form a six membered ring with a Se₄ chain bridging over the 1,4 positions of the Se₆ ring. The anions are made up of BiCl₇ polyhedra connected by common edges to layers all contain an anion of identical formula and two‐dimensional connectivity, but these polymeric chloridobismutates are not isostructural. The structural differences are discussed on basis of the different topologies of the nets made up by the bismuth atoms.