I had asked a question earlier about how the “$\ce{-COOCl}$” functional group would be named.

I had received a satisfactory answer that helped me completely understand how that compound was named.

However, I have a much broader question in mind now.

Consider the "$\ce{-COOH}$" functional group. We know that it's called a carboxylic acid group, however I used to think, why wasn't ethanoic acid simply called as a 1-hydroxyethanal? I now know that "1-hydroxyethanal" has properties vastly different from both aldehydes and alcohols, and as a result, was named differently to acknowledge this difference. Many acid derivatives have been named (and behave) differently, as a result of the $\ce{C=O}$ group nearby.

enter image description here

However, these may not be the only molecules that are affected by the nearby $\ce{C=O}$ group. My earlier question had dealt with the $\ce{-COOCl}$ functional group (not to be confused with acyl chloride $\ce{-COCl}$). However, there are a lot more:

enter image description here

Of course, I did try to name these compounds myself.

  1. Cyanide is sometimes treated as a pseudohalide, so my guess is ethanoyl cyanide.
  2. It may be an anhydride of hydrogen sulfide and ethanoic acid, but I'm not very sure.
  3. Loong gave me an interesting way to name certain "anhydride" compounds in my previous question. This looks like an anhydride of hydroxylamine and ethanoic acid. So according what Loong told me, my guess is ethanoic hydroxylamine anhydride.
  4. This one look's rather crazy to me. Had this been posessing a $\ce{C-O-S}$ instead of a $\ce{C-S}$, this would have been an anhydride of sulfuric acid and ethanoic acid. But it's not, so I have no clue on how to name it.
  5. This one looks very familiar to an amide, infact a phosphorus analog of amide. For some reason, I feel like calling it ethanephosphide, although I don't know why.
  6. Like cyanide, even azide is considered a pseudohalide, so my guess is ethanoyl azide.

Please keep in mind, I am not asking for the explanations to the naming of all the six compounds I showed above, although it would be great if I could get the names alone. Rather, what I mean to ask is is there any simplified nomenclature that can deal with all these types of compounds in a simple way? Although I only showed six, I can go on as long as my imagination permits.

  • 2
    $\begingroup$ I think it is a great question. As a suggestion from my side, could someone also comment on how bright is the idea to use an algorithmic name generation bundled with ChemBioDraw/MarvinSketch for these structures? $\endgroup$
    – andselisk
    Commented Jul 12, 2017 at 11:50
  • 1
    $\begingroup$ I don't know if it's really worthwhile including all your thoughts on the matter. $\endgroup$ Commented Jul 12, 2017 at 11:55
  • $\begingroup$ @orthocresol Well, I asked quite a big question, and it wouldn't be nice if I didn't show a proportional amount of effort that I took before asking someone else to help me. $\endgroup$ Commented Jul 12, 2017 at 12:15
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    $\begingroup$ If I were to write an answer, I wouldn't really want to pay attention to what you've written. I think that writing the correct answer for 6 compounds, complete with justification, is enough work. I've already spoken out, on multiple occasions, about my stance that too much effort is not useful. Maybe I'm the only one who thinks that way, but I just wanted to put it out there for consideration. $\endgroup$ Commented Jul 12, 2017 at 12:16
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    $\begingroup$ These are very different compounds. It's not like you can get whole knowledge of carbonyl compounds' nomenclature in one go. $\endgroup$
    – Mithoron
    Commented Jul 12, 2017 at 13:00

1 Answer 1


The names (2 of 6) are rather correct (but note that acetyl and acetic names are preferred over ethanoyl and ethanoic), except following:

  1. $\ce{Ac-SH}$: ethanethioic acid, more specifically ethanethioc S-acid (since there are two possibilities of “monothiation”)



    thioacetic S-acid
    ethanethioic S-acid (PIN)

    thiopropionic O-acid
    propanethioic O-acid (PIN)

  2. $\ce{Ac-O-NH2}$: Anhydride name cannot be used as hydroxylamine is not a name of acid. It's also not a recognized acid functional group, so the name probably should be regarded a substituted ketone, with preselected prefix aminooxy (P-, 1-(aminooxy)ethan-1-one. (Although pubchem entry lists wrong name: amino acetate; O-acetyl hydroxylamine is acceptable I think.)

  3. $\ce{Ac-SO3H}$: “α-oxosulfonic acid“, 1-oxoethane-1-sulfonic acid
  4. $\ce{Ac-PH2}$: phosphide as alleged analogy to amide (with different meanings in inorg. and org. chem.) is not used, the name should be 1-phosphanylethan-1-one (or acetylphosphane).

    P- Pseudoketones


    1-phosphanylpropan-1-one (PIN)


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