27Al NMR Study of the Structure and Dynamics of Natrolite

NMR Study of Synthetic Gallosilicate Natrolite

“…3). The number of resonance NMR lines of the nuclei 29 Si and 71 Ga determined by the degree of ordered of the natrolite structure [6,14,17]. It has been demonstrated at first by Lipmaa et al [17] that chemical shifts of 29 Si MAS NMR spectra of zeolite and other aluminoosilicates are sensitive to the number of AlO 4 tetrahedra linked to the SiO 4 tetrahedron, also described as the second coordination sphere of silicon.…”

“…It is important to note that the relaxation process for 71 Ga nuclei in Ga-natrolite was well described by a single exponential. It can be assumed that the main physical mechanism responsible for spin-lattice relaxation of 71 Ga nuclei in Ga-natrolite is identical with the mechanism of spin-lattice relaxation of 27 Al nuclei in Al-natrolite and the spin-lattice relaxation of 71 Ga nuclei in Ga-natrolite is concerned with modulation of electric quadrupolar interactions at the sites of the 71 Ga nuclei by thermal motion of water molecules [14]. In this case, the rate of spin-lattice relaxation of 71 Ga nuclei may be described by the equation as [14,[20][21][22][23] (1)…”

“…The temperature dependence of the spin-lattice 1 3 relaxation time T 1 of 71 Ga nuclei has also been studied using solid-state NMR. Obtained results were compared with available references [7][8][9][10][11][12][13][14][15].…”

Proton Dipolar Spin–Lattice Relaxation in Nano-channels of Natrolite

“…From our experimental T 1 and T 1ρ data, it follows that at T > 250 K, the diffusion of water molecules in parallel and perpendicular to the c-axis channels of natrolite is observed [ 15 ]. Our 23 Na and 27 Al NMR investigations show that in temperature range up to 573 K, the phase transitions in natrolite, connected with modifications of the aluminosilicate framework or the structure of pores, are not observed [ 13 , 16 , 17 ]. It follows also from these data that the diffusions of sodium cations in natrolite are absent.…”