\(^{\varvec{23}}\) Na NMR spectra of Na-K form low silica X zeolite loaded with potassium for saturating level, which corresponds to 9.0 atoms per unit, have been observed. Other than a centered grain of the spectral component, another separated peak component with shift of somewhat larger than bulk Na has been detected. Such the extra peak component shows complex hysteresis on temperature and is accompanied with quite slow dynamics of days-order. It is attributed to atomic re-configurations among sites occurs in the course of melting and re-crystallization process among alloy of sodium and potassium, which possibly is formed on surface or outside of the zeolite crystals.
