Open-Framework and Microporous Vanadium Silicates

Abstract

A series of novel vanadium silicates with open-framework and microporous structures has been synthesized under mild hydrothermal conditions. Ten distinct framework types have been identified that all have structures based on cross-linking single silicate sheets with square pyramidal V^IVO₅ units to give compounds with the general formula A_r[(VO)_s(Si₂O₅)_p(SiO₂)_q]·tH₂O, where A is Na, K, Rb, Cs, or a combination. The vanadosilicate (VSH-n) structures have free channel diameters up to 6.5 Å and show good thermal stability, absorption, and ion-exchange properties, suggesting their potential for technological applications as molecular sieves or in catalysis.