Structural aspects of metal-oxide-pillared sheet silicates. An investigation by magic-angle-spinning nuclear magnetic resonance, fourier-transform infrared spectroscopy and powder X-ray diffractometry

Abstract

Variable-temperature powder X-ray diffractometry, Fourier-transform infrared spectroscopy and ²⁷Al and ²⁹Si magic-angle spinning nuclear magnetic resonance spectroscopy have been used to elucidate both the nature of alumina pillars introduced into sheet aluminosilicate and to monitor changes in structure of the host matrix following the introduction of the pillars. The pillars are neutral oxide columns which are structurally similar to γ-alumina; they are linked through oxygen to aluminium and magnesium atoms within the octahedral layer of the clay sheet. The layer charge of the clay is balanced by protons, released during calcination, residing in the aluminosilicate structure.