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 . 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 of a substance caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic ...

product of the

fluorine azide Fluorine azide or triazadienyl fluoride is a yellow green gas composed of nitrogen and fluorine Fluorine is a chemical element; it has Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard temperature an ...

(). It has the structure and exists in both ''cis'' and ''trans'' isomers, as typical for

diimide Diimide, also called diazene or diimine, is a compound having the formula HN=NH. It exists as two geometric isomers, ''E'' (''trans'') and ''Z'' (''cis''). The term diazene is more common for organic derivatives of diimide. Thus, azobenzene is an ...

Isomers

The ''cis'' isomer has C_2v symmetry and the ''trans'' isomer has C_2h symmetry. These isomers can interconvert, but the process is slow enough at low temperature that the two can separated by low-temperature

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

. The ''trans'' isomer is less

thermodynamically stable In chemistry, chemical stability is the thermodynamic stability of a chemical system, in particular a chemical compound or a polymer. Colloquially, it may instead refer to kinetic persistence, the shelf-life of a metastable substance or system; th ...

but can be stored in glass vessels. The ''cis'' isomer 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 factitious air, among others, is a chemical compound, an Nitrogen oxide, oxide of nitrogen with the Chemical formula, formula . At room te ...

: :

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 called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest am ...

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 utili ...

. 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 salt and occurs naturally as the ...

(or

rubidium fluoride Rubidium fluoride (RbF) is the fluoride salt of rubidium. It is a cubic crystal with rock-salt structure. Synthesis There are several methods for synthesising rubidium fluoride. One involves reacting rubidium hydroxide with hydrofluoric acid: ...

caesium fluoride Caesium fluoride (cesium fluoride in American English) is an inorganic compound with the formula CsF. A hygroscopic white salt, caesium fluoride is used in the synthesis of organic compounds as a source of the fluoride anion. The compound is no ...

) which decomposes to dinitrogen difluoride. It can also be prepared by

photolysis Photodissociation, photolysis, photodecomposition, or photofragmentation is a chemical reaction in which molecules of a chemical compound are broken down by absorption of light or photons. It is defined as the interaction of one or more photons wi ...

tetrafluorohydrazine Tetrafluorohydrazine or perfluorohydrazine, , is a colourless, nonflammable, reactive inorganic gas. It is a fluorinated analog of hydrazine. Synthesis Tetrafluorohydrazine was originally prepared from nitrogen trifluoride using a copper as a f ...

and

bromine Bromine is a chemical element; it has chemical symbol, symbol Br and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between th ...

: :

Reactions

The ''cis'' form of difluorodiazene will react with strong fluoride ion acceptors such as

antimony pentafluoride Antimony pentafluoride is the inorganic compound with the formula Sb F5. This colorless, viscous liquid is a strong Lewis acid and a component of the superacid fluoroantimonic acid, formed upon mixing liquid HF with liquid SbF5 in 1:1 ratio. It ...

to form the

linear In mathematics, the term ''linear'' is used in two distinct senses for two different properties: * linearity of a '' function'' (or '' mapping''); * linearity of a '' polynomial''. An example of a linear function is the function defined by f(x) ...

cation (fluorodiazonium cation) which forms a

salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...

with the formula (fluorodiazonium hexafluoroantimonate(V)). : Analogous reaction of ''cis''-difluorodiazene with

arsenic pentafluoride Arsenic pentafluoride is a chemical compound of arsenic and fluorine. It is a toxic, colorless gas. The oxidation state of arsenic is +5. Synthesis Arsenic pentafluoride can be prepared by direct combination of arsenic and fluorine Fluorine is ...

gives white solid salt with the formula (fluorodiazonium hexafluoroarsenate(V)). : In the solid phase, the observed and bond distances in the 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