27Al magic-angle spinning nuclear magnetic resonance satellite transition spectroscopy at 78 MHz has been applied to determine (true) chemical shift and quadrupole coupling parameters of glasses in the system K2O-Al2O3-SiO2 with 60-80 mol% SiO2 and K2O concentrations between 0 and 24 mol%. The powde
Magic-angle spinning nuclear magnetic resonance study of the structure of some PbO-Al2O3-P2O5 glasses
β Scribed by M.W.G. Lockyer; D. Holland; A.P. Howes; R. Dupree
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 900 KB
- Volume
- 5
- Category
- Article
- ISSN
- 0926-2040
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β¦ Synopsis
Some PbO-Al2O3-P2O5 glasses have been investigated using 31P and 27Al magic-angle spinning nuclear magnetic resonance. The observed spectra could be divided into two groups. In the first, Al(IV), Al(V) and Al(VI) are observed, the 31P linewidths are large and the chemical shift range (-30 to -36 ppm) is typical of network phosphate. In the second group, only Al(VI) is observed, the 31P linewidths are much narrower and the shifts are less negative (-18 to -28 ppm).
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27Al nuclear magnetic resonance spectra of polycrystalline aluminium borate 9Al2O3.2B2O3 have been measured in double rotation at 11.7 and 7.0 T and high-speed magic-angle spinning at 7.0, 9.4, 11.7, 14.1 and 17.6 T. Spinning sidebands from the satellite transitions were observed at 7.0 and 14.1 T.
Wide-band (1 MHz) 27Ai magic-angle spinning nuclear magnetic resonance (MAS NMR) spectra were recorded for zeolite Y &/Al \_ 2.7) and high-silica (%/Al u 3.8) FAU, EMT and mixed FAU-EMT structure-type zeolites synthesized using 15crown-5 and/or 18-crown-6 ethers as templating agents. Spinning sideba