Double rotation and magic-angle spinning NMR study of an ultrastable Y zeolite

27 Al double rotation (DOR) NMR is applied to a USY zeolite. It is shown clearly that a fraction of the tetrahedral aluminum species present suffers from second-order quadrupolar anisotropy. This is evident since DOR spinning sidebands of a tetrahedral species clearly appear. This shows the utility of the DOR method for studying highly distorted sites and/or nonframework aluminum sites in zeolites