화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.120, No.10, 2854-2858, 2016
Hexafluorobenzene under Extreme Conditions
We report the results from three high pressure experiments on hexafluorobenzene (C6F6). In the first experiment, Raman spectra were recorded up to 34.4 GPa. A phase transition from I -> II was observed near 2 GPa. Near 8.8 GPa, a phase transition to an unreported phase (III) commenced. Above 20.6 GPa, yet another phase was observed (IV). Pressure cycling was employed to determine that, below 25.6 GPa, all pressure-induced alterations were reversible. However, at pressures above 20 GPa, dramatic spectral changes and broadening were observed at 25.6 and 34.4 GPa. The sample irreversibly changed into a soft solid with waxlike consistency when pressure was reduced to ambient and was recoverable. In the second experiment, IR spectra were collected up to 14.6 GPa. The phase transition (II -> III) near 8.8 GPa was confirmed. An angular dispersive X-ray diffraction experiment was conducted to 25.6 GPa. Phase transitions above 1.4 GPa (I -> II), above 5.5 GPa (II -> III), above 10 GPa (III -> IV), and above 15.5 GPa (IV -> V) were observed. Near 25.6 GPa, long-range crystalline order was lost as the X-ray diffraction spectrum presented evidence of an amorphous solid.