In Situ Synthesis of WF₆ and ReF₆ in a Diamond Anvil Cell and Phase Separation of Products

In recent years, transition metal (TM) fluorides have attracted much attention due to their novel oxidation states and supercoordination under high pressure. However, the strong oxidation and fluorination properties of TM fluorides limit the research on high-pressure experiment. We propose an experimental protocol for the in situ synthesis of TM fluorides in a diamond anvil cell. Solid xenon difluoride (XeF2) and Re and W gaskets served as precursors, while liquid nitrogen (N2) acted as the solvent and pressure-transfer medium. Then, ReF6 and WF6 were synthesized at less than 90 °C and below 1 GPa and confirmed by Raman spectroscopy and microscopic observation. Subsequently, the fluorides were separated from the pressure-transfer medium by the regulation of pressure and temperature. Our work lays the foundation for researching strong oxidizing and fluoridating TM fluorides under high pressure and can also be extended to the in situ synthesis of other chemically active TM fluorides.