Study of vibrational spectra and thermal behavior of sodium fluorocirconate Na$_5$Zr$_2$F$_{13}$

The structure and thermal stability of the compound Na$_5$Zr$_2$F$_{13}$ in the range of temperatures 20–800$^\circ$C was studied by differential thermal and thermogravimetric analysis (DTA-TGA), X-ray diffraction analysis (XRDA) and vibrational spectroscopy.The phase transition to the high-temperature modification $\alpha$-Na$_5$Zr$_2$F$_{13}$ with dynamically disordered structure was confirmed. Infrared (IR) spectroscopy and Raman scattering (RS) spectroscopy data of the compound $\beta$-Na$_5$Zr$_2$F$_{13}$ and its decomposition products upon heating were obtained, systematized and generalized. Based on the results of quantum-chemical calculations, the bands in the vibrational spectra of Na$_5$Zr$_2$F$_{13}$.