Syntheses and structures of barium silanides: Contact and separated ions

The addition of specific donor molecules affects the formation of either contact molecules or separated ions in a series of barium hypersilanides (see picture). Dissociation through the formation of separated ions is observed in aromatic solvents. The silanides are potent initiators in polymerization chemistry and are important as model compounds for the emerging organometallic complexes of the heavy alkaline-earth metals.