The Structure of Hydrated Sodium Fluorophosphatozirconates According to NMR Data

Abstract

²³Na, ³¹P, ¹⁹F, ¹H NMR and MAS NMR methods are used to study compounds Na₂Zr₃F₂(PO₄)₄×3H₂O (I), NaZr₂F₆PO₄·4H₂O (II), and NaZrO_0.5FPO₄·4H₂O (III). It is established that fluorine in these compounds is coordinated to zirconium and occupies terminal positions in fluorophosphatozirconates I and III. Compound II contains both bridging and terminal fluorine atoms. Hypotheses are proposed concerning the nature of fluorophosphatozirconate crystal structure. The presence of translational motions of water molecules and sodium ions in compounds II and III has been established. The activation energy for the mobility of sodium ions in compound III is 0.24 eV.