Fluorine-intercalated graphite

Ohana, I., I. Palchan, Y. Yacoby, and D. Davidov. 1988. Electronic charge transfer in stage-2 fluorine-intercalated graphite compounds. Phys. Rev. B 38 12627-12632. 

FIGURE 12.28 Effects of reaction time and heat treatment on discharge characteristics of fluorine intercalated graphite fibers. (From Touhara, H., et al., Electrochim. Acta, 32, 293, 1987.)... 

Touhara H, Fujimoto H, Kadono K, Watanabe N, Endo M. Electrochemical characteristics of fluorine intercalated graphite fiber-lithium cells. Electrochim Acta 1987 32 293-298. 

Fig. 3. Room temperature F NMR spectra of fluorine-intercalated graphite at 282.4 MHz. In addition to an intensive broad line in the range between —30, —270 ppm, weak broad peaks around 5 0 ppm (shown in inset) exist for some fluorinated compounds the fine structure is not pronounced (reproduced with permission from J. Phys. Condens. Matter, 10 (1998) 7633 [24]).

New aspects on the electrochemical behavior of fluorine-intercalated graphite... 

McCarron, E. M. et al., J. Chem. Soc., Chem. Comm., 1980, 890-891 The solid product of intercalating graphite with germanium tetrafluoride-fluorine mixtures at 20°C is thought to have an oxidising and fluorinating capability close to that of elemental fluorine itself. 

Dining interaction at ambient temperature in a bomb to produce poly (carbon monofluoride), admission of fluorine beyond a pressure of 13.6 bar must be extremely slow and carefully controlled to avoid a violently exothermic explosion [1], Previously it had been shown that explosive interaction of carbon and fluorine was due to the formation and decomposition of the graphite intercalation compound, poly (carbon monofluoride) [2], Presence of mercury compounds prevents explosion during interaction of charcoal and fluorine [3], Reaction of surplus fluorine with graphite or carbon pellets was formerly used as a disposal method, but is no longer recommended. Violent reactions observed when an exhausted trap was opened usually involved external impact on the metal trap, prodding the trap contents to empty the trap, or possibly ingress of moist air... 

The solid product of intercalating graphite with germanium tetrafluoride—fluorine mixtures at 20°C is thought to have an oxidising and fluorinating capability close to that of elemental fluorine itself. 

Vaknin, D., I. Palchan, D. Davidov, H. Selig, and D. Moses. 1986. Resistivity and E.S.R. studies of graphite HOPG/fluorine intercalation compounds. Synth. Metals 16 349-365. 

N. Watanabe, H. Touhara, T. Nakajima, T. Mallouk, H. Selig and N. Bartlett, Foreword and Chap. 8, Fluorine Intercalation Compounds of Graphite, Inorganic Solid Fluorides, Chemistry and Physics, ed. P. Hagenmuller, Academic Press, pp. xiii-xiv and Sec. II, Chap. 8 (1985) 331. 

Touhara, H. Okino, F. Suganuma, S., "Synthesis, Properties, and Functions of Graphite-Fluorine Intercalation Compounds," Kino Zairyo 1991,11,18. 

Watanabe, N. Touhara, H. Nakajima, T. Bartlett, N. Malloxik, T. Selig, H., "Fluorine Intercalation Compounds of Graphite," In Inorganic Solid Fluorides Chemistry and Physics, Hagenmuller, P., Ed. Academic Orlando, FL, 1985 p 331. 

Graphite reacts with alkali metals, for example potassium, to form compounds which are non-stoichiometric but which all have limiting compositions (for example K C) in these, the alkaU metal atoms are intercalated between the layers of carbon atoms. In the preparation of fluorine by electrolysis of a molten fluoride with graphite electrodes the solid compound (CF) polycarbon fluoride is formed, with fluorine on each carbon atom, causing puckering of the rings. 

Whereas superaeid (HF/BF3, HF/SbF, HF/TaF FS03FI/SbF3, etc.)-eatalyzed hydroearbon transformations were first explored in the liquid phase, subsequently, solid aeid eatalyst systems, sueh as those based on Nafion-H, longer-chain perfluorinated alkanesulfonic acids, fluorinated graphite intercalates, etc. were also developed and utilized for heterogeneous reactions. The strong acidic nature of zeolite catalysts was also successfully explored in cases such as FI-ZSM-5 at high temperatures. 

It is used as a fluorinating reagent in semiconductor doping, to synthesi2e some hexafluoroarsenate compounds, and in the manufacture of graphite intercalated compounds (10) (see Semiconductors). AsF has been used to achieve >8% total area simulated air-mass 1 power conversion efficiencies in Si p-n junction solar cells (11) (see Solarenergy). It is commercially produced, but usage is estimated to be less than 100 kg/yr. 

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