Im confused. How to relate permanent dipole dipole moment, temporary dipole induced dipole and Van der waals forces of attractrion?
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$\begingroup$ You can setup a perturbative expansion to include all these dipoles, except covalent bonding. $\endgroup$– RodriguezMay 28, 2016 at 19:23
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1$\begingroup$ Induced dipoles are much like credit money: you can buy goods and use them all right, but still they are not quite yours. $\endgroup$– Ivan NeretinMay 28, 2016 at 19:56
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$\begingroup$ permanent dipole dipole is like a water molecule. temporary dipole is a transient feature that appears to relax the systems energy, Van der waals are a consequence of induced dipoles in larger molecules with more freedom. $\endgroup$– Jordan EpsteinMay 28, 2016 at 21:39
1 Answer
Permanent dipoles are the result of charge separation within a bond, and normally results from bonds where the two elements have a large difference in electronegativity. Dipole moment is a measurement of the polarity of a compound. For example, the carbon-oxygen bond in acetone gives the compound a permanent dipole, explaining its large dipole moment. A temporary dipole occurs when electrons randomly group together in one part of a bond. These dipoles result in London Dispersion Forces, the weakest king of Van der Waals force. Van der Waals forces are a collective term for all residual attractive and repulsive forces between compounds that are not the result of ionic or covalent interactions. Induced dipoles are dipoles that result from a non polar compound becoming polarized as a result of interactions with an ion or polar compound.
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$\begingroup$ So both of them have VDW between molecules? $\endgroup$ May 29, 2016 at 10:33