XeF6 cannot be stored in glass vessel because silica (SiO2)
XeF5⊕
XeO3
XeO2F2
XeOF4
(i) 2XeF6+SiO2⟶2XeOF4+SiF4 (ii) 2XeOF4+SiO2⟶2XeO2F2+SiF4 (iii) 2XeOF4+2SiO2⟶2XeO3+2SiF4