Dinitrogen difluoride is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the formula N₂F₂. It is a gas at room temperature, and was first identified in 1952 as the

thermal decomposition Thermal decomposition, or thermolysis, is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic as heat is re ...

product of the azide N₃F. It has the structure F−N=N−F and exists in both a ''cis''- and ''trans''-form.

Isomers

The ''cis'' configuration lies in a C_2v symmetry and the ''trans''-form has a symmetry of C_2h. These isomers are thermally interconvertible but can be separated by low temperature

fractionation Fractionation is a separation process in which a certain quantity of a mixture (of gases, solids, liquids, enzymes, or isotopes, or a suspension) is divided during a phase transition, into a number of smaller quantities (fractions) in which the ...

. The ''trans''-form is less thermodynamically stable but can be stored in glass vessels. The ''cis''-form attacks glass over a time scale of about 2 weeks to form

silicon tetrafluoride Silicon tetrafluoride or tetrafluorosilane is a chemical compound with the formula Si F4. This colorless gas is notable for having a narrow liquid range: its boiling point is only 4 °C above its melting point. It was first prepared in 1771 ...

and

nitrous oxide Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and has ...

: :2 N₂F₂ + SiO₂ → SiF₄ + 2 N₂O

Preparation

Most preparations of dinitrogen difluoride give mixtures of the two isomers, but they can be prepared independently. An aqueous method involves ''N'',''N''-difluoro

urea Urea, also known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important ...

with concentrated

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which exp ...

. This gives a 40% yield with three times more of the trans isomer. Difluoramine forms a solid unstable compound with

potassium fluoride Potassium fluoride is the chemical compound with the formula KF. After hydrogen fluoride, KF is the primary source of the fluoride ion for applications in manufacturing and in chemistry. It is an alkali halide and occurs naturally as the rare ...

(or rubidium fluoride or caesium fluoride) which decomposes to dinitrogen difluoride. It can also be prepared by photolysis of

tetrafluorohydrazine Tetrafluorohydrazine or perfluorohydrazine, , is a colourless, reactive inorganic gas. It is a fluorinated analog of hydrazine. It is a highly hazardous chemical that explodes in the presence of organic materials. Tetrafluorohydrazine is manufac ...

and

bromine Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table ( halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a simi ...

: :N2F4 -> vBr_2] N2F2 + byproducts

Reactions

The ''cis'' form of dinitrogen difluoride will react with strong fluoride ion acceptors such as antimony pentafluoride to form the N₂F⁺ cation. : N₂F₂ + SbF₅ → N₂F⁺ bF₆sup>− In the solid phase, the observed N=N and N−F bond distances in the N₂F⁺ cation are 1.089(9) and 1.257(8) Å respectively, among the shortest experimentally observed N−N and N−F bonds.

References

{{Nitrogen compounds Inorganic nitrogen compounds Nitrogen fluorides Nonmetal halides