Novel microporous lanthanide silicates with tobermorite-like structure.

The synthesis and structural characterization of microporous lanthanide silicates (Na(1.08)K(0.5)Ln(1.14)Si(3)O(8.5).1.78H(2)O, Ln = Eu, Tb, Sm, Ce) are reported. The structure of these solids is closely related with the structure of hydrated calcium silicate minerals known as tobermorites and was solved by powder X-ray diffraction ab initio (direct) methods and further characterized by chemical analysis, thermogravimetry, scanning electron microscopy, (23)Na and (29)Si MAS NMR and luminescence spectroscopy. These materials combine microporosity with interesting photoluminescence properties, and their structural flexibility allows fine-tuning of luminescence properties, by introducing a second type of lanthanide ion in the framework. Thus, they may find applications in new types of sensors.