Tetrafluorohydrazine or perfluorohydrazine, , is a colourless, reactive
inorganic
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemist ...
gas. It is a
fluorinated
In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers ...
analog of
hydrazine
Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly toxic unless handled in solution as, for example, hydrazine ...
. It is a highly hazardous chemical that explodes in the presence of
organic
Organic may refer to:
* Organic, of or relating to an organism, a living entity
* Organic, of or relating to an anatomical organ
Chemistry
* Organic matter, matter that has come from a once-living organism, is capable of decay or is the product ...
materials.
Tetrafluorohydrazine is manufactured from
nitrogen trifluoride
Nitrogen trifluoride () is an inorganic, colorless, non- flammable, toxic gas with a slightly musty odor. It finds increasing use within the manufacturing of flat-panel displays, photovoltaics, LEDs and other microelectronics. Nitrogen trif ...
using an
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in ...
catalyst or
iron(II) fluoride. It is used in some
chemical syntheses, as a precursor or a
catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
.
Tetrafluorohydrazine was considered for use as a high-energy liquid
oxidizer
An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ). In other words, an oxi ...
in some never-flown
rocket fuel
Rocket propellant is the reaction mass of a rocket. This reaction mass is ejected at the highest achievable velocity from a rocket engine to produce thrust. The energy required can either come from the propellants themselves, as with a chemical ...
formulas in 1959.
Properties
Tetrafluorohydrazine is in equilibrium with its radical monomer
nitrogen difluoride.
: N
2F
4 2 NF
2•
At room temperature N
2F
4 is mostly associated with only 0.7% in the form of NF
2 at 5mm Hg pressure. When the temperature rises to 225 °C, it mostly dissociates with 99% in the form of NF
2.
[ molecule dimensions and angles]
The energy needed to break the N-N bond in N
2F
4 is 20.8 kcal/mol, with an entropy change of 38.6
eu.
For comparison, the dissociation energy of the N-N bond is 14.6 kcal/mol in
N2O4, 10.2 kcal/mol in
N2O2, and 60 kcal/mol in
N2H4. The
enthalpy of formation of N
2F
4 (ΔH
f) is 34.421 kJ/mol.
References
{{Hydrazines
Nitrogen fluorides
Rocket oxidizers
Hydrazines
Gases