Site-directed cation ordering in chabazite-type AlGaPO-34 frameworks revealed by NMR crystallography.

We report the first synthesis of the mixed-metal chabazite-type AlGaPO-34(mim) solid solution, containing 1-methylimidazolium, mim, as structure directing agent (SDA), from the parent mixed-metal oxide solid solution, γ-(AlGa)O. This hitherto unreported family of materials exhibits complex disorder, arising from the possible distributions of cations over available sites, the orientation of the SDA and the presence of variable amounts of water, which provides a prototype for understanding structural subtleties in nanoporous materials. In the as-made forms of the phosphate frameworks, there are three crystallographically distinct metal sites: two tetrahedral MO and one octahedral MOF (M = Al, Ga).