Effect of H-1-decoupling in two-dimensional multiple-quantum MAS NMR spectroscopy of Na-23 in a hydrous layered silicate

In order to check the efficiency of high-power H-1 decoupling when used with the two-dimensional multiple-quantum MAS method recently proposed to obtain isotropic spectra from quadrupolar nuclei, we applied this new technique to Na-23 NMR for a hydrous layered silicate compound, makatite, with and without H-1 decoupling. A remarkable improvement of the spectral resolution in the isotropic dimension was observed by the decoupling, showing that it is effective in the 2D MQ-MAS method and suggesting that proton decoupling should be generally applied in Na-23 experiments concerning these kinds of compound. (C) 1997 Elsevier Science B.V.