Nitrogen Fluorine Compounds

Nitrogen Fluorine Compounds 

inorganic compounds containing a N—F bond, for example, nitrogen trifluoride, NF₃, tetrafluorohydrazine, N₂F₄, difluoramine, NF₂H, and nitrosyl fluoride, FNO. Nitrogen fluorine compounds are colorless gases, with a characteristic odor. They decompose upon heating into individual elements or into nitrogen trifluoride and nitrogen (with the exception of NF₃ and FNO). They exhibit strong oxidizing properties. Certain nitrogen fluorine compounds react with organic compounds to form numerous organic substances containing the —NF₂ and —NONF groups. One characteristic feature of nitrogen fluorine compounds is that, on interaction with strong Lewis acids (seeACIDS AND BASES), they form salts with the fluorine-nitrogen cations NF⁺₄, N₂F⁺₃, N₂F⁺₄, and F₂NO⁺.

Nitrogen trifluoride, NF₃, is a gas, with a melting point of – 208.5°C and a boiling point of –129.1°C. Its oxidizing ability is manifested at high temperatures. It is converted into tetrafluorohydrazine at elevated temperatures and in the presence of copper, iron, mercury, or carbon. It is obtained by the electrolysis of molten ammonium bifluoride or by the fluorination of nitrogen-containing substances. It is used in the preparation of tetrafluorohydrazine.

Tetrafluorohydrazine, N₂F₄, is a gas, with a melting point of –161.5°C and a boiling point of –74.2°C. It tends to dissociate: N₂F₄⇄2NF₂. At 150°C and a pressure of 0.1 meganewton/m² (1 kilogram-force/cm²), its degree of dissociation is 0.2. The dissociation of N₂F₄ determines its difluoraminating effect, which is manifested, for example, on combination with olefins:

Tetrafluorohydrazine is obtained by the conversion of nitrogen trifluoride over coal (commercial method), by the decomposition of NF₂H, or by the oxidation of its solutions. It is used in the synthesis of organic difluoramine compounds.

Difluoramine, NF₂H, is a gas with a melting point of – 116°C and a boiling point of – 23°C. It explodes on impact, especially in the liquid and solid states. It exhibits amphoteric properties and in reactions acts as a difluoraminating agent. It is obtained by the action of sulfuric acid on difluoraminourea (a fluorination product of urea) or on triphenylmethyl difluoramine, synthesized from N₂F₄ and triphenylmethyl chloride in the presence of mercury. It is used for the synthesis of organic difluoramine compounds.

REFERENCE

Pankratov, A. V. Khimiia ftoridov azota. Moscow, 1973.

A. V. PANKRATOV