Two substituted cubic octameric silicate cages in aqueous solution

Abstract

Two novel silicate anions, a singly-substituted cubic octamer (double four-ring cage with a pendant orthosilicate group) and its dimeric counterpart (two octameric cages linked by a single siloxane bridge), are detected by 29Si NMR spectroscopy in concentrated tetraalkylammonium silicate solutions at the low alkalinity and high SiO2 concentration typical of zeolite synthesis slurries.