At temperatures above −35.9 °C, xenon tetroxide is very prone to explosion, decomposing into xenon and oxygen gases with ΔH = −643 kJ/mol:
:XeO → Xe + 2 O
Xenon tetroxide dissolves in water to form perxenic acid and in alkalis to form perxenate salts:
:XeO + 2 HO → HXeO
:XeO + 4 NaOH → NaXeO + 2 HO
Xenon tetroxide can also react with xenon hexafluoride to give xenon oxyfluorides:
:XeO + XeF → XeOF + XeOF
:XeO + 2XeF → XeOF + 2 XeOF