Silicon site distributions in an alkali silicate glass derived by two-dimensional 29Si nuclear magnetic resonance

Influence of magnesia on the structure and properties of bioactive glasses

“…There seems to be no evidence of any further Q species within the series, therefore a binary distribution model for the glasses is suggested, agreeing with earlier work by Lockyer et al [3] and Elgayar et al [5]. It is noted, however, from previous work that more than two Q n species can coexist at all compositions, suggesting a model based on the disproportionation reaction shown by equation (1) [23,48].…”

Pressure-induced structural changes and densification of vitreous MgSiO3

“…In this study, the lower frequency shoulder in the 29 Si MAS NMR spectrum of the non-compressed MgSiO 3 glass shown in Fig. 3 is located over a chemical shift range that is primarily characteristic of Q 3 species (Stebbins and McMillan, 1993;Zhang et al, 1996;Zhang et al, 1997). The pressure-induced disappearance of the low frequency shoulder can be associated with a Q species reaction that results in the consumption of Q 3 species such as: 2Q 3 = Q 2 + Q 4 and Q 1 + Q 3 = 2Q 2 (Xue et al, 1991;Kubicki et al, 1992).…”

Structure of H2O-saturated peralkaline aluminosilicate melt and coexisting aluminosilicate-saturated aqueous fluid determined in-situ to 800°C and ∼800MPa

“…The basis for the assignments is a comprehensive spectroscopic and theoretical data base (e.g., Brawer and White, 1975;Furukawa et al, 1981;McMillan, 1984;Stebbins, 1987Stebbins, , 1988Maekawa et al, 1991;Buckermann et al, 1992;McMillan et al, 1992;Zhang et al, 1996;Maekawa and Yokokawa, 1997;Zotov and Keppler, 1998, 2002Mysen et al, 2003;Cody et al, 2005). A possible exception to this broad agreement may be found in Malfait et al (2007).…”