Tetrachloromethane nonpolar molecule

If the four atoms attached to the central atom in a tetrahedral molecule are the same, as in tetrachloromethane (carbon tetrachloride), CCI4 (30), the dipole moments cancel and the molecule is nonpolar. However, if one or more of the atoms are replaced by different atoms, as in trichloromethane (chloroform), Cl ICI, or by lone pairs, as in NH3, then the dipole moments associated with the bonds are not all the same, so they do not cancel. Thus, the CHCI, molecule is polar (31). 

Predict whether each of the following molecules is likely to be polar or nonpolar (a) CCl4 (tetrachloromethane) ... 

If a nonpolar component (aliphatic hydrocarbon or tetrachloromethane) is added, almost nothing happens (Figure 3.8a). The solubility of octane in either the micellar solution or the liquid crystal is very limited. This is true of any molecule exhibiting only dispersion cohesive forces (induced dipole-induced dipole van der Waals forces). 

Results of gelation tests are summarized in Table 2.12. The fluids to be gelled range from protic solvents to aprotic ones, from polar solvents to nonpolar ones, and from mineral oils to edible ones. It is obvious that both 80 and 81 are excellent organogelators whose gelation abilities are comparable to those of 68 and 69. For example, the amount of 80 necessary to gel one liter of acetonitrile, N,N-dimethylformamide, ethanol, ethyl acetate, tetrachloromethane, toluene and hexane are 5 g, 10 g, 33 g, 8 g, 23 g, 12 g and 6 g, respectively. This means that one molecule of 80 interacts with about 1800 molecules of acetonitrile, 600 molecules of A,A -dimethylformamide, 200 molecules of ethanol, 600 molecules of ethyl... 

As already mentioned, chlorides of methane are very useful solvents. From the knowledge about the polarity of molecules, i.e. their dipole moments, we can distinguish between polar and nonpolar solvents. The polar solvents are for example CH2CI2 and CHCI3, while tetrachloromethane, CCI4, is a nonpolar solvent. Polarity of solvents is one of the most important properties, not only for practical laboratory applications, but also for the theory of reaction mechanisms, reactivity and selectivity of organic compounds. 

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