29Si NMR studies of the transformation of silicate anions in the system Na2O·SiO2·nH2O (n= 9,5) in crystals, melts, and solution
Abstract
A combined solid- and liquid-state 29Si NMR study shows that the monomeric silicate anions of crystalline sodium silicate hydrates Na2H2SiO4·nH2O (n= 8,4) upon melting undergo rapid condensation to distinct oligomer species, and that recrystallization of the melt involves hydrolysis of the oligomers and reconstitution of the initial monomeric silicate structure.