A two-dimensional silicon-29 nuclear magnetic resonance spectroscopic study of the structure of the silicate anions present in an aqueous potassium silicate solution

Abstract

The results of two-dimensional silicon-29 n.m.r. homonuclear correlation spectroscopy (COSY) experiments performed on a nominally 1.5 mol dm^–3, 1 : 1 potassium silicate solution prepared with isotropically enriched ²⁹SiO₂ are consistent with the simultaneous presence of 22 silicate anions in solution. These include all of the species proposed in earlier double resonance studies. The results suggest that the additional species are silicate cages containing mixtures of both Q² and Q³ groups in four-membered rings, and possible structures are discussed.