LINE-SHAPES AND WIDTHS OF MAS SIDE-BAND FOR AL-27 SATELLITE TRANSITIONS - MULTINUCLEAR MAS NMR OF TUGTUPITE NA8AL2BE2SI8O24CL2

A multinuclear Be-9, Na-23, Al-27, and Si-29 magic-angle spinning (MAS ) NMR study has been performed for the mineral tugtupite (Na8Al2Be2Si8 O24Cl2). The extremely well-resolved spectra allow observation of sepa rate spinning sidebands (ssb's) from the inner (+/-1/2, +/-3/2) and ou ter (+/- 3/2, +/- 5/2) Al-27 satellite transitions, and are utilized i n a detailed analysis of the line shapes and widths of the individual ssb's from simulations. The line widths of the ssb's from the inner an d outer Al-27 Satellite transitions are found to decrease systematical ly with increasing order of the ssb's across the spectrum. Accurate va lues for the Be-9, Na-23, and Al-27 quadrupole coupling parameters and isotropic chemical shifts are obtained from simulations of the manifo lds of ssb's from the satellite transitions. MAS NMR of the Be-9 satel lite transitions for tugtupite, BeO, and beryl (Al2Be3Si6O18) shows th at these transitions are particularly useful for determination of Be-9 quadrupole couplings because of the small 9Be quadrupole moment. The Si-29 shielding anisotropy of delta(sigma) = 48 ppm in tugtupite is th e largest determined so far for a framework SiO4 tetrahedron. Finally, the crystal structure of the tugtupite sample has been refined by sin gle-crystal X-ray diffraction, and correlations between the multinucle ar NMR parameters and structural data are reported.