Synthesis of xenon trioxide is by aqueous hydrolysis of :
: + 3  →  + 6 HF
The resulting xenon trioxide crystals are a strong oxidising agent and can oxidise most substances that are at all oxidisable. However, it is slow-acting and this reduces its usefulness.
Above 25 °C, xenon trioxide is very prone to violent explosion:
:2 XeO → 2 Xe + 3 O (ΔH = −403 kJ/mol)
When it dissolves in water, an acidic solution of xenic acid is formed:
:XeO(aq) + HO → HXeO  H + 
This solution is stable at room temperature and lacks the explosive properties of xenon trioxide. It oxidises carboxylic acids quantitatively to carbon dioxide and water.
Alternatively, it dissolves in alkaline solutions to form xenates. The  anion is the predominant species in xenate solutions. These are not stable and begin to disproportionate into perxenates (+8 oxidation state) and xenon and oxygen gas. Solid perxenates containing  have been isolated by reacting  with an aqueous solution of hydroxides. Xenon trioxide reacts with inorganic fluorides such as KF, RbF, or CsF to form stable solids of the form .