Dinitrogen difluoride

CAS Registry Numbers 2 2 [10576-16-2], trans-N2F23776-62-07, cis-N2F2 773672-43-67 General References  

Lawless, I. C. Smith, Inorganic High-Energy Oxidizers, Dekker, New York 1968, pp. 35/44. J. K. Ruff, Derivatives of the Nitrogen Fluorides, Chem. Rev. 67 [1967] 665/80, 673/4, 678. 

Colburn, Nitrogen Fluorides and Their Inorganic Derivatives, Advan. Fluorine Chem. 3 [1963] 92/116, 103/6. 

It has been known since 1959 that N2F2 exists in two isomeric forms which differ in their physical and chemical properties, i.e., their melting points, boiling points [1,2], vapor pressures, critical temperatures, heats of vaporization [1], mass-spectral fragmentation patterns [1,3,4], and chemical reactivity towards, e.g., glass or mercury [1,5]. It has been firmly established by electron diffraction [6], vibrational IR spectra [1,4, 7], N and F NMR spectra [8], rotational microwave spectra [9], and mass-spectral fragmentation patterns [1,3, 4] that the two isomers are the cis and trans forms of planar dinitrogen difluoride, F-N=N-F, as had 

Several well-defined routes with respect to working conditions, product yields, and purities are known for preparing N2F2  

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Two volumes of hydrogen fluoride gas combine with one volume of the gas dinitrogen difluoride to form two volumes of a gas G. 

There are two structures possible for dinitrogen difluoride, which is also known as difluorodiazine. These structures can be shown as follows ... 

Nitrogen trifluoride is prepared by electrolysis of either molten ammonium fluoride, NH4F, or melted ammonium acid fluoride, NH4HF2 (or ammonium fluoride in anhydrous HF). Whde the NH4F method is preferred because it forms nitrogen trifluoride as the only product, electrolysis of ammonium acid fluoride yields a small amount of dinitrogen difluoride, N2F2, and NF3. 

Nitrogen Triftuoride, NFg, mw 71.01 colorless gas or mobile liquid sp gr 1.537, fr p —206.6°, bp —128.8°. It is one of the Nitrogen Fluorine Compounds. Others are Dinitrogen Tetra-fluoride, Dinitrogen Difluoride and Difluor-amine. They are powerful oxidizers suitable for both liquid and solid rocket proplnrs. Also used for high energy fuels Refs 1) Gmelin-Kraut Syst Number 5(1959), 238 2) CondChemDict (1961), 805-L (1971),... 

The axis about which the rotation takes place is the symmetry element In this case trans-dinitrogen difluoride is said to have a two-fold rotational axis. Note that if the operation is performed twice, all atoms are back in their initial positions.5... 

Now consider cis-dinitrogen difluoride (Fig. 3.6). It possesses no axis perpendicular to the plane of the molecule that allows rotation (other than the trivial 360° one) and qualifies as a symmetry element. However, it is possible to draw an axis that lies in the plane of the molecule equidistant between the two nitrogen atoms and also equidistant between the two fluorine atoms. This is also a two-fold axis Rotational axes are denoted by the symbol C , representing the n-fold axis. Thus cis- and irans-dinitrogen difluoride each have a C2 axis. 

Spears, L. G., Hackerman, N. Analysis of fluorine, hydrogen fluoride, nitrogen trifluoride, trans dinitrogen difluoride and dinitrogen tetrafluoride mixture by gas chromatography. J. Gas Chromatog. 6, 392 (1968). 

The compound N2F2, also known as dinitrogen difluoride, exists in two forms ... 

The predominant product depends on conditions, especially the F2/NH3 ratio. Dinitrogen difluoride may also be prepared by photolysis of N2F4 in the presence of Br2. 

Anhydrous difluoramine decomposes thermally (in the presence of KF as HF absorber) to dinitrogen difluoride. 

Dinitrogen difluoride is best synthesized by passing difluoramine over KF. 

If rotation of a molecule by 360" ln results in an indistinguishable configuration, the molecule is said to have an n-fold rotational axis. Consider trans-dinitrogen difluoride (Fig. 3.5). If we construct an axis perpendicular to the plane of the paper and midway between the nitrogen atoms, we can rotate the molecule by 180° and obtain an identical configuration. Rotation by 180° is thus a symmetry operation. 

Rotational axes are denoted by the symbol C , representing the n-fold axis. Thus CIS- and tra/is-dinitrogen difluoride each have a C2 axis. 

Fig. 3.5 The two-fold rotational axis in trans-dinitrogen difluoride. The two-fold axis is perpendicular to the plane of the paper and denoted by the symbol...

Dinitrogen difluoride, N2F2, was first identified in 1952 as a thermal decomposition product of the azide N3F and it also occurs in small yield during the electrolysis of NH4F/HF (p. 439), and in the reactions of NF3 with Hg or with NF3 in a Cu reactor (p. 439). Fluorination of NaNs gives good yields on a small scale but the compound is best prepared by the following reaetion sequenee ... 

Difluorodiazene (dinitrogen difluoride), N2F2, is a gas consisting of two isomers (12-XII) and (12-XIII). The m-isomer predominates ( 90%) at... 

All halogen azides are sensitive and explode easily. The sensitivity decreases in the order FN3 > CIN3 > BrNs > IN3. Fluorine azide decomposes to form dinitrogen difluoride and dinitrogen. 

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