Pressure-Induced Phase Transitions of Hydrous Zirconium Tetrafluoride

The high pressure behaviors of hydrous zirconium tetrafluoride have been investigated by in situ synchrotron X-ray diffraction, Raman spectroscopy and infrared (IR) absorption measurements. The phase transition occurs under high pressure (0–28 GPa). The α phase transforms into β phase at 7.3 GPa and then γ phase at 13.2 GPa. The high pressure γ phase can be quenched to the starting phase when pressure is releasing to 0 GPa, indicating the reversible phase transition. Furthermore with increasing pressure, fluid molecular water occurs around 11.0 GPa from starting structurally bonded water state according to IR absorption which offer a clue to obtain pury anhydrous salts because of instability of hydrous zirconium tetrafluoride under ambient conditions.