Solid-state 29Si and 27Al NMR studies of natural mesolite

摘要: Abstract A natural zeolite specimen from Pune, India, was studied using 1D (29Si, 27Al) and 2D (27Al) multi-quantum (MQ) solid-state NMR. The signals of silicon alumina spectra were assigned empirical relationships between the bilateral Si–O–Al angles in a framework corresponding chemical shifts. While three distinct 29Si MAS NMR at −86 to −89 ppm single Sin(3Al) sites (n = 2–4), largest one −95.5 ppm shown be composed two Si environments, Si1(2Al) Si5(2Al). complex 27Al single-Bloch decay spectrum mesolite could not properly without resorting 3MQ experiment. It that arising 3 different crystallographic positions aluminum discerned spectra. quadrupolar parameters Al obtained. Finally, treatment with oxalic acid carried out, leading partially dealuminated sample. Small, albeit selective, removal predominantly T3 observed upon dealumination.