XeF6 cannot be stored in glass or quartz containers as XeF6 reacts with SiO2 present in the glass as shown below:
SiO2+2XeF6→2XeOF4+SiF4
SiO2+2XeOF6→2XeO2F2+SiF4
SiO2+2XeO2F2→2XeO3+SiF4