Studies on silicic acid and its salts: XV. 29Si NMR study of sodium silicate in solution

The 29Si NMR study of aqueous solution of sodium silicate of mole ratio SiO2 to Na2O equals one shows that the degree of polymerization of sodium silicate decreases with the decrease of the concentration, but the concentration of monosilicate anion increases, and that the lower the salt concentration, the faster is the rate of increase of the anionic concentration. The effect of SiO2/Na2O mole ratio and the concentration of sodium silicate on chemical shifts and spin-lattice relaxation time, T1, of Si species and the effect of salt on degree of polymerization of sodium silicate in solution were also investigated.