Mixed Network Phosphate Glasses: Seeing Beyond the 1D 31P MAS-NMR Spectra With 2D X/31P NMR Correlation Maps

Lithium-lead phosphate and borophosphate glasses were studied in compositional series of xLi2O-(50-x)PbO-50P2O5, xLi2O-(50-x)PbO-10B2O3-40P2O5 and xLi2O-(50-x)PbO-20B2O3- 30P2O5. All glasses crystallize on heating within the range of 400-610oC. Their glass transition temperature decreases with increasing Li2O content in the region of x = 0-30 mol% Li2O and then slowly increases in all series of glasses reflecting thus changes in the bond strength of the glass structural network. Density, molar volume and chemical durability of the glasses decrease with increasing Li2O content. The 31P MAS NMR and Raman spectra show that at all glass series with the replacement of PbO by Li2O the ratio of Q2/Q1 units, present in the structure, slightly increase. The 11B MAS NMR spectra of glasses with 10 mol% B2O3 reveal the presence of only BO4 units in the glass structure, whereas the spectra of the glasses with 20 mol% B2O3 reveal also the presence of small amount of BO3 units.

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Solid State MAS-NMR and FTIR Study of Barium Containing Alumino-Silicate Glasses

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.361-363.825 ◽

2007 ◽

Vol 361-363 ◽

pp. 825-828 ◽

Cited By ~ 6

Author(s):

Fei Wang ◽

Artemis Stamboulis ◽

D. Holland ◽

Shigeki Matsuya ◽

Akari Takeuchi

Keyword(s):

Nmr Spectra ◽

Magic Angle Spinning ◽

Mas Nmr ◽

Silicate Glasses ◽

Magic Angle ◽

Ftir Study ◽

Alumino Silicate ◽

31P Mas Nmr ◽

Angle Spinning ◽

Second Peak

The glass based on a 1.5SiO2-Al2O3-0.5P2O5-CaO-0.67CaF2 composition was produced and substituted gradually by barium. The structure of the glasses was studied by multinuclear Magic Angle Spinning Nuclear Magnetic Resonance (MAS-NMR) and Fourier Transform Infrared Spectroscopy (FTIR). It was indicated by 29Si and 31P MAS-NMR spectra that silicon was present as Q4 (4Al) and Q3 (3Al) species and phosphorus was in a Q1 pyrophosphate environment. 29Al MAS-NMR spectra showed that four fold coordinated aluminum Al (IV) was the dominant species with a second peak assigned to octahedral aluminum Al (VI). The 19F spectra suggested that the barium addition caused the formation of Al-F-Ba(n) and F-Ba(n) species. Furthermore, a distribution of silicate network including Si-O-Si stretching (Q4 and Q3) and Si-O-[NBO] (Q3) per SiO4 was reflected by the FTIR study.

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Investigation of Phosphorus Site Condensation in CaHPO4 by Analysis of 31P MAS-NMR Tensor and X-Ray Powder Patterns

Zeitschrift für Naturforschung A ◽

10.1515/zna-2006-7-811 ◽

2006 ◽

Vol 61 (7-8) ◽

pp. 375-382 ◽

Cited By ~ 5

Author(s):

Faouzi Hlel ◽

Saber Kamoun ◽

Kamel Guidara

Keyword(s):

Nmr Spectroscopy ◽

Nmr Spectra ◽

Room Temperature ◽

Chemical Shifts ◽

Mas Nmr ◽

Slow Evaporation ◽

X Ray Diffraction ◽

X Ray ◽

Annealing Temperatures ◽

31P Mas Nmr

CaHPO4 was obtained by slow evaporation at room temperature. Seven samples, obtained at different annealing temperatures, were characterized by X-ray diffraction and 31P MAS-NMR spectroscopy. All NMR spectra were analyzed using a DMFIT program. At room temperature, the observed 31P NMR chemical shifts for the title compound were −1.59, −0.36 and 1.26 ppm with the relative intensities 39%, 10% and 51%, revealing the presence of three non-equivalent phosphorus sites in the structure. The investigation of the NMR tensor shift of all spectra shows that the abounding HPO2−4 anion was progressively transformed into P2O4−7 when the temperature increased

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