Fluorine, thermodynamic data

Table 1. Thermodynamic Data for Steps in Fluorination of Methane1 ...

Whatever one s interpretation of fluorine chemistry, sub-, super-, or super-super-balogen, it is obvious that the thermochemistry is extremely important to the understanding the chemistry of fluorine. It is fortunate that good, thorough thermodynamic data on fluorine compounds arc available.- ... 

The current, critical evaluation of the ideal gas thermodynamic data on the f1uoromethanes (8) and f1uoroethanes 9) will be particularly appropriate to the reduction of C-H bond dissociation energy data. Additional data on the enthalpy of formation of fluorine containing compounds will be recalculated (if necessary) to reflect the recent, direct determination of AH2(HF-nH20, 298) of Johnson, Smith and Hubbard (10). The data for the reference states, C(graphite), H2(g) and p2(g) are the same as those used by Rodgers et al. (8). 

The standard electrode potential of fluorine cannot be measured directly because F2 reacts with water, displacing O2. Using thermodynamic data from Appendix D, obtain a value of... 

Thermochemistry. Thermodynamic considerations ate of utmost importance in fluorinations. Table 1 is based on JANAF data (25) for CH, which indicate an average carbon-hydrogen bond strength of 410.0 kj/mol (98 kcal/mol) based on the atomization energy of CH. ... 

Fluorine thermochemistry itself has not been previously reviewed, but has tended to be included in more general reviews and reports, or in data compilations (141,123,151). The most comprehensive literature survey, covering the years 1949-1961 (9), supplements the N.B.S Circular and Notes (203). (N.B.S. Technical Notes 270-3 to 270-7 issued from 1969-1973 were unfortunately published without literature references.) Subsequent work was conveniently traced from annual issues of the Bulletin of Chemical Thermodynamics, and from 1977 to 1979 (May) by accessing the Chemical Abstracts data files. Experimental aspects of fluorine thermochemistry are included in two rather dated volumes (214), and only general detail will be given in this review. 

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