SOLID-STATE NMR AND ESCA STUDIES OF THE FRAMEWORK ALUMINOSILICATE ANALCIME AND ITS GALLOSILICATE ANALOG

A detailed ESCA and solid-state NMR study has been carried out of the aluminosilicate analcime (Si/Al = 1.82) and its gallosilicate analogue (Si/Ga = 2.68). The core level binding energies in (Si,Al)-analcime are consistent with that for framework materials of similar elemental composition. The shift of binding energies in (Si,Ga)-analcime suggests an increased ionicity of the Ga-O bond compared to the Al-O bond. The ionicity of the Ga-O bond is substantially lower than in cloverite, a GaPO4 molecular sieve, as a result of the greater covalency of the P-O bond compared to the Si-O bond.