To observe the structural transformation, the solutions prepared by path 2 are heated. When the Zn 2+ //F -//Na + //ClO4 -solutions prepared by path 2 with 0.001-0.12 mol•kg -1 ZnF2 are heated at 80 o C with 24 h, the F NMR spectral feature of those cooled solutions is close to those of solutions prepared by path 1, as shown in Fig. .