Oxygen Fluorides

compounds that contain an O—F bond, such as oxygen difluoride, OF₂, dioxygen difluoride, O₂F₂, fluorine nitrate, FNO₃, and fluorine perchlorate FC1O₄. Fluorine forms with oxygen in a glow discharge a mixture of stable F—O—O radicals and fluorine atoms; condensation of the mixture at – 196°C yields higher oxygen fluorides, such as O₂F₂ and O₃F₂, which are stable only at low temperatures. All oxygen fluorides are strong oxidizing agents.

Oxygen difluoride, OF₂, is a colorless gas, with a characteristic pungent odor. Highly toxic, it has a density of 1.521 g/cm³ at – 145°C, a melting point of –224°C, and a boiling point of – 145°C. It gradually decomposes into the individual elements at a temperature of about 200°C. Pure oxygen difluoride is not explosive. It dissolves poorly in water, undergoing hydrolysis. Liquid OF₂ is freely soluble in liquid fluorine, oxygen, and ozone. In terms of chemical properties, OF₂ is a strong oxidizing agent; it fluorinates metals on slight heating and explodes on reaction with water, hydrogen, or halogens when triggered by a spark or when heated. OF₂ is obtained by the fluorination of an aqueous solution of caustic soda or caustic potash: 2F₂ + 2NaOH = OF ₂+ 2NaF + H₂O; it is also obtained by the electrolysis of an aqueous HF solution.

Dioxygen difluoride, O₂F₂, is an unstable compound. On interaction with Lewis acids, it forms salts of the dioxygen cation O⁺₂; for example, O₂F₂ + SbF₅ = O₂SbF₆ + l/2F₂. It is prepared from a mixture of fluorine and oxygen in a glow discharge at a temperature of – 196°C. It is used in the laboratory as a strong fluorinating or oxidizing agent.