A high-resolution solid-state nuclear magnetic resonance study of the ordering of silicon and aluminium in synthetic mazzite (zeolite omega)

The 29Si m.a.s.n.m.r. spectrum of synthetic mazzite is the sum of two mutually overlapping families of signals due to the presence of two kinds of crystallographically non-equivalent silicon atoms. Unlike zeolites in which all silicons are equivalent (such as synthetic faujasite), the resultant spectral peaks cannot be directly assigned to various Si(nAl) structural building blocks. We show how considerations based on high-field 27Al and 29Si n.m.r. of the parent and dealuminated mazzite enable us to calculate the populations of Si and Al on each type of site and to assign the spectra fully.