To explore the aging time effect, both Zn 2+ //F -//Na + //ClO4 -solutions with 0.04 mol•kg -1 ZnF2 prepared by paths 1 and 2 are monitored using NMR spectrometer (Tables and, Fig. ). Within 4 days, the results show that only single 19 F NMR signal is observed for the solution prepared by path 2 whereas there are both signals for that prepared by path 1. At the 4 th day, the second signal at ~-130 ppm is also observed for the solution prepared by path 2. However, the peak strength (or its integral area) is weaker (or smaller), compared to the signal of solution prepared by path 1. As the aging time increases and is up to 19 months, the spectral difference, including the number of signal or strength of peak at ~-130 ppm, always exists, indicating that the microstructural subtle difference of both solutions at 25 o C is stable and independent of aging time.