Unusual structural changes going from Li+ to Cs+ in [W(CN)6(bpy)]2− ion salts: the Na+ case

Abstract

Two complexes of the formula Na₂[W(CN)₆(bpy)]·6H₂O (1) and Na₂[W(CN)₆(bpy)]·5H₂O·CH₃CN (2) were synthesized, structurally characterized, described and compared with their lithium, potassium, rubidium and cesium analogues. This finalizes the description of structures of [W(CN)₆(bpy)]²⁻ ion salts with all alkali metals. The salts crystalize in the triclinic P space group. In all the salts, layered structures are observed with weak hydrophobic bpy–bpy zipper like interactions between layers. The unexpected changes in W–W distance, thickness of layers, density and other parameters going from Li⁺ to Cs⁺ are described and discussed.