In recent years Choudhury lab has designed a series of 2D quaternary chalcogenides involving a variety of building units, including simple tetrahedral, supertetrahedral, and ethane-like moieties. These 2D materials are synthesized by a building-block approach, in which preformed building blocks containing alkali ions react with metal (transition, rare-earth, or main-group) chlorides in so-called solid-state metathetic reactions. In these reactions, alkali ions are partially or fully replaced by the metal from the metal chloride, generating alkali halides by-products that drives the reaction forward. In all these compounds, 2D layers are formed through various connectivities of metal polyhedra and main-group building units, with alkali (Li or Na) ions occupying the interlayer spaces. However, crystal structure determination of these materials is often challenging due to stacking faults within the layers.

In this presentation, we will discuss a range of properties exhibited by these 2D materials, including spontaneous water and ammonia adsorption, ion conduction, and their potential use as cathode materials in lithium-ion batteries.

Finally, we will present our ongoing efforts to develop new 2D materials in a more rational manner, including our work to understand their formation through in situ X-ray diffraction techniques using synchrotron radiation.