Xenon tetroxide

Xenon tetroxide (molecular formula XeO₄) is a yellow crystalline solid that is stable below -35.9°C. Xenon here has an oxidation state of +8 and oxygen of -2. All eight valence shell electrons of xenon are involved, making it an unstable compound. Above -35.9°C, however, it explodes to give xenon and oxygen gas. Oxygen is the only element that can bring xenon up to its highest oxidation state, even fluorine can only give XeF₆ (xenon hexafluoride). Xenon tetroxide dissolves in water to give perxenic acid, and in alkalis to give the perxenate ion.