Preparation, characterization, spectral and conductivity studies of Na3MgZr(PO4)3 and Na0.1(H3O)2.9MgZr(PO4)3

Na3MgZr(PO4)3 and Na0.1(H3O)2.9MgZr(PO4)3 were prepared by microwave heating and ion exchange methods respectively. They were characterized by powder XRD, energy dispersive spectroscope (EDS), IR, Raman, TGA/DTA, DC conductivity and 31P-MAS NMR spectra. These two compounds crystallized in the hexagonal NASICON lattice with R 3¯ c space group. The EDS spectra show the replacement of Na+ by H3O+ ions. The infrared and Raman spectra exhibit characteristic vibrational bands of PO4 tetrahedra and metal–oxygen vibrations. The DTA and TGA studies respectively indicate the structural phase transformations and absence of weight loss in these phosphates. The activation energies for conduction was found to be higher Na3MgZr(PO4)3 compare to the value obtained for Na0.1(H3O)2.9MgZr(PO4)3 and the values obtained are 0.41 and 0.082 eV (in the temperature range 27–165 and 165–360 °C) respectively. The DC conductivity of Na3MgZr(PO4)3 is higher than the conductivity of Na0.1(H3O)2.9MgZr(PO4)3. The conductivity values are found to be as σdc = 1 × 10−4 Ω−1 cm−1 and σdc = 1 × 10−6 Ω−1 cm−1at 250 °C respectively. The 31P-MAS NMR spectra show the presence of two chemically different environments around phosphorous in these compounds.