For carbon tetrafluoride

FIGURE 15. A panoramic UPS-XPS for carbon tetrafluoride, CF4, showing valence and core ionizations, and a fluorine Auger process. Reproduced by permission of the Royal Swedish Academy of Sciences from Reference 36... 

A sixth type of heat of immersion curve can be predicted from the isosteric heats determined by Graham [9] for carbon tetrafluoride and other gases on polytetrafluorethylene. The prediction can readily be made from the equation ... 

Representing a two electron covalent bond by a dash (—) the Lewis structures for hydrogen fluoride fluorine methane and carbon tetrafluoride become... 

Uses. The chemical inertness, thermal stability, low toxicity, and nonflammability of PFCs coupled with their unusual physical properties suggest many useflil applications. However, the high cost of raw materials and manufacture has limited commercial production to a few, small-volume products. Carbon tetrafluoride and hexafluoroethane are used for plasma, ion-beam, or sputter etching of semiconductor devices (17) (see loN implantation). Hexafluoroethane and octafluoropropane have some applications as dielectric gases, and perfluorocyclobutane is used in minor amounts as a dielectric fluid. Perfluoro-1,3-dimethyl cyclohexane is used as an inert, immersion coolant for electronic equipment, and perfluoro-2-methyldecatin is used for... 

Fig. 4.—Radial distribution curves for carbon and silicon tetrafluorides and silicon, germanium and tin tetrachloride.

Model A cannot be eliminated definitely by the photographs there are, however, some points which make this model improbable. From the curve for this model the first minimum would be expected to be at least as well pronounced as the second minimum, whereas on the photographs the first minimum is not very well defined. That the qualitative appearance of the photographs supports model C rather than model A is further shown by the fact that the photographs resemble those of methyl nitrate more closely than those of carbon tetrafluoride. Some evidence is also provided by the radial distribution curve (Fig. 1), the first peak being displaced by 0.15 A. from the position expected for it for model A. For these reasons and the additional reason that it is difficult to correlate the tetrahedral configuration with an electronic structure involving only completed octets, we consider model A not to be satisfactory.7... 

Carbon monoxide Carbon tetrafluoride F T Copper-lined metals for pressures <34 bar. Certain highly alloyed chrome steels Any common metal Iron, nickel and certain other metals at high pressures... 

Carbon tetrafluoride and all polyfluorinated hydrocarbons are very stable and inert molecules. This inertness can be attributed to the strength of the CF bonds and the close packing of the inert fluoride-like ligands around the carbon atom, which effectively prevent attack by a nucleophile on the carbon atom. In contrast, even though BF3 has stronger bonds than CF4, it is more reactive, forming adducts such as BF3-NH3 because the boron atom is only three-coordinated and there is space around it for an additional ligand. 

Per luoroethylene),F3C CF2 mw 100.02 col gas, fr p -142.5°, bp -78.4° insol in w. Was prepd by Humiston (Refs 1 2) by treating charcoal with fluorine carbon tetrafluoride was obtd at the same time. Accdg to Ref 3, it can be prepd by passing chlorodifluoromethane thru a hot tube. Serves as a raw material for prepn of polytetrafluoroethylene polymers... 

Moissan attempted to harness elemental fluorine for organic synthesis, but found that he could not control the reactions, as combustion or detonation usually occurred.1 From carbon itself (and also in other ways), he claimed to have made carbon tetrafluoride, but this was not correct as the quoted boiling point was far too high. In fact, the isolation of fluorine had virtually no impact on the synthesis of organic fluorides for over 40 years. 

The other important factor to affect the operational conditions of the cell is the voltage increase between the carbon and copper lead. This problem has been solved individually in industry. For example, a 250 pm thick layer of nickel can be coated onto the upper part of the carbon anode using the atmospheric plasma spraying method.7 This electrode has been operated at 15 to 17 A dm-2 in a 1000 A scale industrial cell for 19 months. The cell voltage was 9.5 V and polarization did not occur with this electrode. Characteristic points of this new carbon electrode are low polarizability and no anode effect, and the concentration of carbon tetrafluoride contaminating the fluorine is below 2 ppm. 

Clearly the ionic model (first column) prohibits too much it prohibits, Sidgwick notes, "even so stable a molecule as carbon tetrafluoride. On the other hand, the covalent model (second column) allows too much it allows, Sidgwick observes, "ample room, not only for the number of attached atoms in actual stable molecules, but for far more than are ever found even in the imaginary Cl6 there would be space left between the iodine atoms. ... 

Figure 11.10 Meyer-Overton correlation for volatile general anesthetics in mice. The slope of the regression line is -1.02 and the correlation coefficient, r2 = 0.997. CTF, carbon tetrafluoride NIT, nitrogen ARG, argon PFE, perfluoroethane SHF, sulfur hexafluoride KRY, krypton N02, nitrous oxide ETH, ethylene XEN, xenon DDM, dichlorodifluoromethane CYC, cyclopropane FLU, fluroxene DEE, diethylether ENF, enflurane ISO, isoflurane HAL, halothane CHL, chloroform MOF, methoxyflurane.

Sample Draw a Lewis structure for the molecule CF4, carbon tetrafluoride. 

Write formulas for each of the following compounds (a) carbon tetrafluoride, (b) xenon hexafluoride, and (c) sulfur difluoride. 

The simplest fluorocarbon, carbon tetrafluoride, CF4, is an inert gas, bp -128 °C, which is made commercially by direct fluorination of carbon. Carbon tetrafluoride is used in the electronics industry for the purpose of dry etching of silicon. ... 

---