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Is hydrogen bonding separate from permanent dipole interactions? What I mean here is that a molecule such as ethanol has hydrogen bonding, but does it also have permanent dipoles other than the ones on the oxygen and hydrogen atoms that cause permanent dipole attraction?

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Consider the three hydroxyphenols catechol (ortho-hydroxyphenol), resorcinol (meta-), and hydroquinone (para-). All three engage in hydrogen bonding with their hydroxyl groups. But they differ in polarity. Hydroquinone, with its hydroxyl groups symmetrically placed on opposite corners of the benzene ring, has a limited (average) dipole moment between two conformations, one polar and one nonpolar, whereas the other two isomers have an additional dipole from their hydroxyl groups being nonsymmettically located and have larger overall dipole moments.

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  • $\begingroup$ You mean pyrocatechol. $\endgroup$ – Poutnik Dec 22 '19 at 12:19
  • $\begingroup$ @poutnik ? ? ? ? $\endgroup$ – Oscar Lanzi Dec 22 '19 at 13:08
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    $\begingroup$ ortho-hydroxyphenol. :-) But I see they are synonyms, and the first time I may missed you mentioned catechol. $\endgroup$ – Poutnik Dec 22 '19 at 13:09
  • $\begingroup$ Hydroquinone has a dipole moment. $\endgroup$ – Martin - マーチン Dec 22 '19 at 13:39
  • $\begingroup$ How is a permanent moment rendered? Will the vector change direction if bonds rotate? $\endgroup$ – Oscar Lanzi Dec 22 '19 at 13:57

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