Chlorine trifluoride dioxide is an inorganic compound of chlorine, fluorine, and oxygen with the chemical formula ClO2F3.

[1] Synthesis of chlorine trifluoride dioxide can be by a reaction of chlorine monofluoride with dioxygen difluoride:[2] Alternatively it can be made by a reaction of chlorine trifluoride with oxygen gas:[2] Chlorine trifluoride dioxide is a colorless gas at standard conditions.

[3] ClO2F3 reacts with water.

[4]