Preparation, characterization and conductivity studies of NaAlSb(PO₄)₃ and HAlSb(PO₄)₃

Abstract

NaAlSb(PO₄)₃ and HAlSb(PO₄)₃ are prepared by solid-state and metathesis reactions respectively. They are characterized by powder XRD, IR and solid-state ³¹P-MAS NMR spectroscopy. These two compounds crystallize in the hexagonal NASICON structure with the space group of <i>R</i><img src='/image/spc_char/3_bar.gif'><i>C</i>. Their infrared spectra exhibit characteristic vibrational bands of PO₄ tetrahedra. The ³¹P-MAS NMR spectra of NaAlSb(PO₄)₃ and HAlSb(PO₄)₃ are characterized by a symmetric single peak around 9 ppm suggesting only one

<b style=""></b>type of phosphorous in the hexagonal lattice. The activation energies for conduction and relaxation are more for NaAlSb(PO₄)₃ compared to the values of HAlSb(PO₄)₃. The isothermal conductivity of NaAlSb(PO₄)₃i

s higher than the conductivity of HAlSb(PO₄)₃. The imaginary parts of the impedance, (<i>Z''</i>) and electric modulus (<i>M''</i>) against log frequency show single peaks in both <i>Z''</i> and <i>M''</i> spectra.