Nonhydrolytic Synthesis of NASICON of Composition Na3Zr2Si2PO12: A Spectroscopic Study

NASICON (Na 3 Zr 2 Si 2 PO 12 ) has been prepared by a nonhydrolytic route reacting OP(OBu) 3, SiCl 4, Zr(O t -Bu) 4, and NaO t -Bu in acetonitrile. The progress of the reaction was monitored by measuring 31 P and 13 C NMR spectra in the liquid phase and mass spectra of the reaction mixture. The spectroscopic analysis allowed optimization of the synthetic conditions. The thermal decomposition behavior of the precursor was studied by simultaneous thermogravimetric and differential thermal analysis. The NASICON precursor was heated to selected temperatures, and the resulting powders were analyzed by X-ray diffraction to check the formation of the NASICON phase. The powder obtained at 900 °C was almost pure, showing only traces of free zirconia.