Lone-Pair Interfaces That Divide Inorganic Materials into Ionic and Covalent Parts

摘要

Compounds containing main-group metals in low oxidation states frequently exhibit stereochemically active lone pairs.In particular,this is observed for compounds of Sn~(II),Pb~(II),As~(III),Sb~(III),Bi~(III),and Te~(IV).An intriguing phenomenon is the localization of such lone pairs to well-defined regions of the solid-state structures of these compounds,wherein the volumes of lone pairs form surfaces that separate regions of different kinds of chemical interaction.Interestingly,lone pairs tend to aggregate and even more so they tend to aggregate together with negatively charged ions.Here we show a striking example of how this segregation effect can be used to template solid-state compounds with reduced dimensionality.