Chemical Bonding State of Sulfur in Na₂S-SiO₂ Glasses

Sulfur speciation and network structural changes in sodium silicate glasses: Constraints from NMR and Raman spectroscopy

“…As mentioned in the Introduction, peaks near Ϫ55 ppm and Ϫ25 ppm have been previously observed in glasses synthesized from Li 2 S-SiS 2 -Li 4 SiO 4 and Na 2 S-SiO 2 at ambient pressure (Tatsumisago et al, 1996;Asahi et al, 1998), and our recent ab Fig. 2.…”

“…Tatsumisago et al (1996) studied glasses in the Li 2 S-SiS 2 -Li 4 SiO 4 system with 29 Si magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy and observed peaks near Ϫ55 and Ϫ25 ppm, in addition to those expected for SiS 4 and SiO 4 groups, and attributed these additional peaks to SiO n S 4-n (n ϭ 1 to 3) groups. Asahi et al (1998) studied glasses synthesized from Na 2 S-SiO 2 with both 29 Si MAS NMR and X-ray photoelectron spectroscopy (XPS), and identified two similar peaks in the 29 Si-NMR spectra, in addition to those expected for the SiO 4 groups. Our recent ab initio molecular orbital calculations (Xue and Kanzaki, 2004a) suggested that these peaks are due to SiO 3 S (near Ϫ55 ppm) and SiO 2 S 2 (near Ϫ25 ppm) groups.…”

“…Our recent ab initio molecular orbital calculations (Xue and Kanzaki, 2004a) suggested that these peaks are due to SiO 3 S (near Ϫ55 ppm) and SiO 2 S 2 (near Ϫ25 ppm) groups. Asahi et al (1998) also inferred that some of the sulfur could be present as sodium sulfide clusters in the more sodium-rich glasses. Konijnendijk and Buster (1977) have studied several sodium, potassium, and calcium silicate glasses doped with sulfates, and McKeown et al (2001) studied borosilicate glasses doped with sulfates, both with Raman spectroscopy.…”

Porous, S‐bearing silica in metal‐sulfide nodules and in the interchondrule clastic matrix in two EH3 chondrites

“…Measurements of the bonding state of S in Na 2 S‐SiO 2 glass using X‐ray photoemission spectroscopy, magnetic angle spinning, and nuclear magnetic resonance indicated the electron density was close to that of S 2− in the glass with low alkali ion concentration (Asahi et al. ). The detection of S 2− is consistent with S substitution for a silicon‐bound oxygen atom functioning as a nonbridging sulfur (Hanada et al.…”