| cis-Dinitrogen difluoride (left) and trans-Dinitrogen difluoride (right)[1] | |
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cis- or trans-dinitrogen difluoride |
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Other names
cis- or trans-difluorodiazine |
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| Identifiers | |
| CAS number | 13812-43-6, (cis) [13776-62-0] (trans) |
| ChemSpider | 4516471 |
| Jmol-3D images | Image 1 Image 2 |
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| Properties | |
| Molecular formula | N2F2 |
| Molar mass | 66.010 g/mol |
| Appearance | colorless gas |
| Density | 2.698 g/L |
| Melting point |
cis: < -195 °C |
| Boiling point |
cis: -105.75 °C |
| Dipole moment | cis: 0.16 D trans: 0 D |
| Thermochemistry | |
| Std enthalpy of formation ΔfH |
cis: 69.5 kJ/mol trans: 82.0 kJ/mol |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Dinitrogen difluoride is a chemical compound with the formula N2F2. It is a gas at room temperature, and was first identified in 1952 as the thermal decomposition product of the azide N3F. It has the structure F-N=N-F and exists in both a cis- and trans-form. These isomers are thermally interconvertible but can be separated by low temperature fractionation. 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 and nitrous oxide:[2]
Most preparations of dinitrogen difluoride give mixtures of the two isomers, but they can be prepared independently.
The cis form of dinitrogen difluoride will react with strong fluoride ion accepters such as antimony pentafluoride to form N2F+ cation.
In the solid phase of N2F+ compound, the observed N−N and N−F bond distances of 1.089(9) and 1.257(8) Å, respectively, are among the shortest experimentally observed N−N and N−F bonds