4000 mg · kg -1 ( LD50, mouse, oral)
( -178.029 · X 4.519 ) kJ · mol -1
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Graphite fluoride, CFx is a non-stoichiometric solid fluorocarbon compound, can take in the x values between 0 and 1.24. Depending on the fluorine content of graphite fluoride appears black (x ≤ 0.9), brown -gray ( 0.9 < x ≤ 1.0 ) or creamy - white ( x > 1.0 ). Graphite fluoride was first synthesized by Otto Ruff and Bretschneider by reaction of graphite with fluorine Norit or at elevated temperature.
Graphite fluoride can be obtained by reaction of ordered carbon such as graphite, as well as of disordered substrates after heat treatment such as pyrolysis and even lamp black with fluorine in a temperature range 400-700 ° C are generated. Basically, a highly ordered material such as graphite always delivers a higher proportion of graphite fluoride as eg a " graphitized " lamp black, in which the proportion of volatile fluorocarbons, such as carbon tetrafluoride, CF4 dominated. At higher temperatures ( above 700 ° C) only volatile fluorocarbon compounds are formed.
In the fluorination of graphite whose layer structure is always preserved. However, the distance between the carbon layers, depending on the type of preparation and composition of the graphite fluoride by forming the tertiary C-F units and the strong electrostatic repulsion of 335 pm of graphite significantly up to 580 - 615 pm expanded. The structure of the layers is turbostratic, however, that is superposed layers are in parallel, but take another one no preferential orientation. The individual C6F6 elements of the layers are in a chair conformation with each axially stationary fluorine atoms, as shown in the above structural formula. In contrast to the graphite fluoride, which is a fluorocarbon compound having covalent C-F bonds can be obtained by reaction of fluorine with, for example, carbon at low temperatures and a wide range of graphite fluoride intercalation of the general composition CYF y = 2-10, are produced.
In contrast to the anisotropic electrical conductor, graphite is the reaction product of graphite fluoride, with the ideal stoichiometry CF, an insulator. In a fluorination below x = 0.9 graphite fluoride conducts electricity as well as graphite. Graphite fluoride is a superhydrophobic material with water shows a contact angle of 143 °, while polytetrafluoroethylene for comparison provides a contact angle of 109 °. Graphite fluoride with stoichiometries between x = 0.61 to 1.12 is excellent lubricating properties, especially in the high temperature range, the yet to be achieved neither of molybdenum sulphide of graphite. Graphite fluoride decomposes at temperatures above 600 ° C under substantially dismutation to difluorocarbene, tetrafluoroethene and expandable graphite.
Graphite fluoride is used today mainly as a cathodic depolarizer in the lithium - carbon monofluoride battery. Graphite fluoride accelerates the burnout of boron in solid propellant compositions by effective removal of the oxide layer to form carbon monoxide and boron trifluoride. In addition, there is a very high-energy oxidizer in infrared decoys and air-breathing propulsion When the exothermic reaction of graphite fluoride with reducing agents, among other nanostructured reaction products such as SiC fibers and carbon nanotubes are formed.