Английская Википедия:Dinitrogen difluoride

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Шаблон:Short description Шаблон:Chembox

Dinitrogen difluoride is a chemical compound with the formula Шаблон:Chem2. It is a gas at room temperature, and was first identified in 1952 as the thermal decomposition product of the fluorine azide (Шаблон:Chem2). It has the structure Шаблон:Chem2 and exists in both cis and trans isomers, as typical for diimides.

Isomers

The cis isomer has C2v symmetry and the trans isomer has C2h symmetry. These isomers can interconvert, but the process is slow enough at low temperature that the two can separated by low-temperature fractionation.Шаблон:Clarify The trans isomer is less thermodynamically stable[1] but can be stored in glass vessels. The cis isomer attacks glass over a time scale of about 2 weeks to form silicon tetrafluoride and nitrous oxide:[2]Шаблон:Page needed

Шаблон:Chem2

Preparation

Most preparations of dinitrogen difluoride give mixtures of the two isomers, but they can be prepared independently.

An aqueous method involves N,N-difluorourea with concentrated potassium hydroxide. This gives a 40% yield with three times more of the trans isomer.[3]

Difluoramine forms a solid unstable compound with potassium fluoride (or rubidium fluoride or caesium fluoride) which decomposes to dinitrogen difluoride.[3]

It can also be prepared by photolysis of tetrafluorohydrazine and bromine:[4]

Шаблон:Chem2 Шаблон:Overunderset Шаблон:Chem2

Reactions

The cis form of difluorodiazene will react with strong fluoride ion acceptors such as antimony pentafluoride to form the linear[5] Шаблон:Chem2 cation (fluorodiazonium cation[5]) which forms a salt with the formula Шаблон:Chem2 (fluorodiazonium hexafluoroantimonate(V)).

Шаблон:Chem2

Analogous reaction of cis-difluorodiazene with arsenic pentafluoride gives white solid salt with the formula Шаблон:Chem2[5] (fluorodiazonium hexafluoroarsenate(V)).

Шаблон:Chem2

In the solid phase, the observed Шаблон:Chem2 and Шаблон:Chem2 bond distances in the Шаблон:Chem2 cation are 1.089(9) and 1.257(8) Å respectively, among the shortest experimentally observed N-N and N-F bonds.

References

Шаблон:ReflistШаблон:Nitrogen compounds