Mixtures of crystalline proton type zirconium phosphate, HZr
2(PO
4)
3, with M
INO
3 (M
I = Li, Na, K, Rb, Cs) and M
II(NO
3)
2 (M
II = Mg, Ca, Sr, Ba) were thermally treated at 700°C for 5 h, in order to investigate the immobilization of M
I and M
II. All M
I and M
II immobilized products gave X-ray diffraction (XRD) patterns attributable to M
IZr
2(PO
4)
3 and M
IIZr
4(PO
4)
6 with a NASICON-type structure, and had the same crystal state as HZr
2(PO
4)
3. The
a-axis lattice constant of M
IZr
2(PO
4)
3 and M
IIZr
4(PO
4)
6 decreased monotonically with increasing the ionic radius of M
I and M
II, respectively, while the
c-axis lattice constant increased. The electrical conductivity of M
IZr
2(PO
4)
3 and M
IIZr
4(PO
4)
6 sintered at 1400°C decreased with increasing the ionic radius of M
I and M
II, respectively. Leaching tests for M
IZr
2(PO
4)
3 and M
IIZr
4(PO
4)
6 were carried out at 160°C for 24 h in 1 mol·dm
-3-HCl. The leaching rate decreased with increasing ionic radius of M
I and M
II, except for the case of Rb and Cs in M
IZr
2(PO
4)
3 and Sr and Ba in M
IIZr
4(PO
4)
6.
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