Unique pore selectivity for Cs+ and exceptionally high NH4+ exchange capacity of the chalcogenide material K6Sn[Zn4Sn4S17].

摘要: Highly selective ion-exchange properties and -exchange capacities of the open framework chalcogenide material K6Sn[Zn4Sn4S17] (1) with Cs+ NH4+ are reported. Because structure this is known in great detail, these studies a rare example where structure/property relationships can be directly drawn. 1 possesses three types micropore cavities. The largest pore presents an exact fit for exhibits high selectivity ion, as demonstrated by competitive experiments. next has greater capacity (up to four cations) well suited ions. This leads ammonium-exchange 3.06 mequiv/gr, which close NH4+-exchange natural zeolites. single-crystal structures ammonium-exchanged products at various stages reveal unusual mechanism exchange process involves diffusion ammonium cations from large cavity small ones framework. Thermal analysis...