Structure and NMR assignment in AlPO₄-15:A combined study by diffraction, MAS NMR and first-principles calculations

A multi-technique investigation involving X-ray diffraction, solid-state NMR and first-principle calculations was carried out on the aluminophosphate material AlPO4-15. A synchrotron X-ray single-crystal diffraction study was carried out on the same sample as that used in solid-state NMR studies. The model from the single crystal study, together with a model from a literature high resolution study of the same material, was used as starting points for the first-principles calculations of the NMR parameters. This enabled the P-31 and Al-27 NMR spectra to be unambiguously assigned and all the NMR parameters calculated agreed well with the experimental spectra even without relaxing the X-ray derived structural models. (C) 2009 Elsevier Masson SAS. All rights reserved.