Which of the following xenon compounds may not be obtained by hydrolysis of xenon fluorides?

XeF6 + 3H2O → XeO3 + 6HF

Hydrolysis of xenon fluorides leads to the formation of various xenon oxides and oxyfluorides. XeF6 on hydrolysis gives XeO3. Partial hydrolysis of XeF4 and XeF6 can lead to the formation of XeOF4 and XeO2F2 respectively. However, XeO4 cannot be obtained by the hydrolysis of xenon fluorides. Therefore, XeO4 is the compound that may not be obtained by hydrolysis of xenon fluorides.