Abstract
A new sodium zinc di(phosphate/arsenate) Na2ZnP1.5As0.5O7 has been synthesized as polycrystalline powder by solid-state reaction at 550 degrees C, and its structure was determined by using the Rietveld refinement. The structural model of Na2ZnP1.5As0.5O7 has been supported by the two models of validation the charge distribution (CHARDI) and bond valence sum (BVS). The vibration mode of the diphosphate-diarsenate absorption bands has been studied by infrared spectroscopy technique. As quantitative analysis, ICP-MS has been used to prove the Na2ZnP1.5As0.5O7 formula, especially P/As ratio. The electrical properties of the title compound have been determined by impedance spectroscopy in the 330-560 degrees C temperature range. The conductivity varied between 1.14 10(-7) S.cm(-1) at 330 degrees C and 7.41 10(-6) S.cm(-1) at 500 degrees C and the activation energy value is Ea=0.937 eV. The simulation of sodium transport pathways by the means of the BVSE (bond valence site energy) model shows 2D pathways in the interlayer's space. The empirical activation energy deduced from the BVSE model is about 0.936 eV.