Hydrothermal synthesis and structural investigation of sodium zirconium silicophosphates
The hydrothermal reactions of NaZr2(PO4)3 with Na2SiO3 in excess NaOH at 300°C have been investigated. The pure precursor phases have been obtained at the reactant ratio of NaZr2(PO4)3∶Na2SiO3 from 1∶1 to 1∶3.2. When the reactant ratio reached 1∶3.5 in the case of a large excess of NaOH, Na4Zr2(SiO4)3 was obtained. The structures of the precursor phases were studied by X-ray diffraction, infrared and magic angle spinning nuclear magnetic resonance spectroscopy. The results showed that these NASICON-like phases were similar to 6.06 phase designated by Clearfieldet al., which were converted into sodium zirconium silicophosphates on heating to 1000°C. All NASICON phases prepared by this process were pure phases and free ZrO2 remained. The structure and ionic conductivity of these NASICONs have been investigated and the results compared with literature data. The compounds in some of the range of composition appear to have a maximum ionic conductivity at 300°C (0.2 Ω−1 cm−1). This method provides a very effective and convenient route for preparing all compounds in the NASICON family.
KeywordsNuclear Magnetic Resonance Nuclear Magnetic Resonance Spectroscopy Ionic Conductivity Magnetic Resonance Spectroscopy Resonance Spectroscopy
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- 7.Yong Yue andWenqin Pang,Chem. J. Chinese Univ. 12 (1991) 585.Google Scholar