IUPAC Gold Book defines alcohols as:

Compounds in which a hydroxy group, $\ce{–OH}$, is attached to a saturated carbon atom $\ce{R3COH}$.

However, Wikipedia says that:

Vinyl alcohol, also called ethenol (IUPAC name), is an alcohol.

Is Wikipedia wrong about this?

And if ethenol is not an alcohol, what would be the correct name for compounds in which an $\ce{–OH}$ group is attached to an unsaturated carbon atom?

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    $\begingroup$ Ethenol is not a thing at all, which pretty much makes the question void. Unsaturated carbons don't survive near -OH, unless we're talking about phenols. $\endgroup$ Nov 3, 2017 at 15:37
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    $\begingroup$ Why is it not a thing? It's the enol tautomer of acetaldehyde... @IvanNeretin $\endgroup$
    – Zhe
    Nov 3, 2017 at 15:38
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    $\begingroup$ @IvanNeretin No argument there, but seems excessive to say "not a thing at all." $\endgroup$
    – Zhe
    Nov 3, 2017 at 15:54
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    $\begingroup$ One could use a similar argument to say that tennessine is not a thing at all. Still there are a lot of scientific articles published about it. $\endgroup$
    – ttsc
    Nov 3, 2017 at 16:11
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    $\begingroup$ related: chemistry.stackexchange.com/questions/729/… $\endgroup$
    – Mithoron
    Nov 3, 2017 at 19:00

1 Answer 1


The golden book states that ethenol is an alcohol:


Alkenols; the term refers specifically to vinylic alcohols, which have the structure $\ce{HOCR'=CR2}$.

However, the modifier "vinylic" is rather important, so I would never omit it.

  • $\begingroup$ So, should Wikipedia be edited? What would be a good wording? Would it be good to change it for example to: "Vinyl alcohol, also called ethenol (IUPAC name), is an enol. It's not an alcohol according to the IUPAC definition, because the $\ce{–OH}$ group is not attached to a saturated carbon atom." $\endgroup$
    – ttsc
    Nov 4, 2017 at 16:35
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    $\begingroup$ I personally think that the IUPAC definition is not really on point, here's why: one needs to distinguish carbon acids, thiocarbon acids etc. and alcohols, and that's not easy to word. For wikipedia, the wording "Vinyl alcohol, also called ethenol (IUPAC name), is the prototypical vinylic alcohol" may be sensible. $\endgroup$
    – TAR86
    Nov 4, 2017 at 16:48
  • $\begingroup$ The distinction "attached to saturated carbon atom" is quite on point. Also phenol is not an alcohol. Enoles are chemically even much more different from alcohols than phenols. $\endgroup$
    – Karl
    Oct 13, 2018 at 17:03

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