NMR-STUDY OF SODIUM DISPERSED IN ZEOLITES

The electronic state of sodium metal dispersed in the cavities of zeol ites was investigated by nuclear magnetic resonance. The dehydrated Na -zeolite samples were loaded with additional sodium by vapor transport . Using spin echo techniques at 77 K, a quadrupolar broadened Na-23 sp ectrum, assigned to Na introduced into zeolites NaX and NaY superimpos ed on the host framework Na-23 spectrum, was observed. Nuclear relaxat ion measurements reveal a rapid relaxation component of likely electro nic origin. The temperature dependence and indications of magnetic ord er at low temperature suggest that the introduced Na is better describ ed as interacting paramagnetic cluster ions than as metallic sodium cl usters.