A 69Ga and 71Ga MAS NMR study of the gallium analogue zeolite ZSM-5

• Published in: Chemical physics letters Vol. 176; no. 3; pp. 399 - 403
• Main Authors: Kentgens, A.P.M., Bayense, C.R., van Hooff, J.H.C., de Haan, J.W., van de Ven, L.J.M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 1991; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Nuclear magnetic resonance and relaxation; Physics; Quadrupole resonance; Magic angle; Chemical shift; Nuclear magnetic resonance; Zeolite; Experimental study; Magnetic field; Quadrupolar interaction; Spectral line width
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/0009-2614(91)90051-A

69Ga and 71Ga magic-angle-spinning (MAS) NMR spectra of a series of gallium analogue zeolites H—(Ga)ZSM-5, with varying Si/Ga ratios, were obtained at 14.1 and 7.1 T. The quadrupole coupling constant e 2qQ/h was deduced from the shift difference of the centre of gravity of the 69Ga and 71Ga resonance. An analysis of the linewidth as a function of the magnetic field shows that the width is not only determined by the second-order quadrupolar broadening, but also by a distribution of chemical shifts. The values obtained for the quadrupole coupling constant and chemical shift distribution are compared to those found for 27Al in H—(Al)ZSM-5. It is argued that the observed differences are related to the different NMR properties of the isotopes, and do not point to any structural changes of the ZSM-5 lattice.