Sodium Ion Exchange in

2 3 Na two-dimensional nutation N M R was applied to N a t + *Zr 2 Si v P 3 _ v O, 2 with x = 0, 1, and 2. The nutat ion spectrum in each compound consists of two clearly separated peaks corresponding to the two crystallographically inequivalent sodium sites. In the compound with x = 2 the nuclear quadrupole coupling constants (e Qq/h) and the asymmetry parameters (rj) were by spectral simulation estimated to be 1.0 M H z and 0 for one site, and 1.5 M H z and 0.8 for the other site. The spectrum varies considerably on heating; the two peaks merge into a single peak at high temperatures due to fast ion exchange between the two different sites. For x = 0 and x = 1 the nutation spectra did not show any significant temperature dependence, suggesting that the rates of the sodium ion exchange are negligibly low.