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 Se-4[Bi4Cl14], Se-8[Bi4Cl14], and Se-10[Bi5Cl17] was discovered. Red, transparent, plate shaped crystals of Se-10[Bi4Cl14] 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 degrees C. The crystal structure consists of bicyclic Se-10(2+) 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 Se-4 chain bridging over the 1,4 positions of the Se-6 ring. The anions are made up of BiCl7 polyhedra connected by common edges to layers (2)(infinity)[Bi4Cl142-]center dot Se-4[Bi4Cl14], Se-8[Bi4Cl14], Se-10[Bi4Cl14], and Te-8[Bi4Cl14] all contain an anion of identical formula and two-dimensional connectivity, but these polymeric chlorido-bismutates are not isostructural. The structural differences are discussed on basis of the different topologies of the nets made up by the bismuth atoms.