Talk:Carbon–oxygen bond

Missing content: carboxylic acids
The article is missing the carboxylic acid functional group. R-COH=O. —Preceding unsigned comment added by 70.28.78.36 (talk) 13:55, 2 October 2009 (UTC)

Move discussion in progress
There is a move discussion in progress on Talk:Carbon-carbon bond which affects this page. Please participate on that page and not in this talk page section. Thank you. —RM bot 17:30, 30 April 2011 (UTC)

Explanation of added tags
First, the citation tags were added for obvious reasons; two of the three references are to books without page numbers, and the third is to a bare URL. There are good, thorough undergraduate texts (e.g., Clayden), advanced organic texts (Lowry and Richardson, Carey and Sundberg, etc.), several further good physical organic texts, and many ACS and other physorg series with chapters and data (i.e., good secondary sources). There is absolutely no reason to give factual data without references; even if the facts are common knowledge (only partly true here) and non-controversial, the point is to educate, and sourcing and further developing the text will make clear that there is some subtly involved in these concepts (oxonium example, see following), and that there are resource so that a person can go to learn more.

Second, the inline tags in the following paragraph were added because the first sentence lacks required subtlety to be accurate:

"Internal C=O bonds are found in positively charged oxonium ions, but occur mainly as reactive intermediates. In furans, the oxygen atom contributes to pi-electron delocalization via its filled p-orbital and hence furans are aromatic. Bond lengths of C=O bonds are around 123 pm in carbonyl compounds. The C=O bonds in acyl halides have partial triple bond character and subsequently very short: 117 pm. Compounds with formal C–O triple bonds do not exist except for carbon monoxide, which has a very short, strong bond (112.8 pm). Such triple bonds have a very high bond energy, even higher than N–N triple bonds. Oxygen can also be trivalent, for example in triethyloxonium tetrafluoroborate."

Apart from the needing to reword the "internal C=O bonds" bit (which is at odds with last sentence and link out), please consider: if the resonance structure shown at the linked out oxonium ion page contributes, is choice of "C=O" and the wording of the rest of the sentence the best way to express this idea? Then, oxonium ions are dealt with twice in the paragraph, at beginning and end (bring together?), and when mentioned at end in the context of a discussion of bond lengths, no bond lengths are given for this species. Hence, I propose this paragraph needs at least this further work.

Third, the later expand section tag: The reactions producing C-O bonds content is so limited and elementary, and therefore off-point with regard to modern organic chemistry (in scope and priorities), that it would be better to omit this section, rather than leave it as is. My view; expand significantly soon, based on content of a modern graduate level OChem text (at least), or move to Talk, until it is ready for prime time. (Hint, what do organoboranes have to do with the paragraph? or hetero-Diels-Alder reactions?)

Finally, I collapsed the "See also", because it is voluminous, colorfully inviting, and, unfortunately, immaterial to the main article. People can and should notice and open that, but only after exploring the article. If it stays, it needs to be far less prominent, and this was the simplest way I could see to make it readily accessible but not overwhelming.

See how this all fits. Cheers, Le Prof Leprof 7272 (talk) 07:17, 10 June 2014 (UTC)


 * that is a lot of new tags but all of them necessary?

V8rik (talk) 20:57, 10 June 2014 (UTC)
 * adding page numbers to citations is not a priority. It is doubtful if you can get volunteers to add these page numbers.
 * expansion tags are not effective, they will not attract volunteers. They only clutter a page
 * the sources lacking tags in the "Oxygen functional groups" section: the fact offered here is "Carbon–oxygen bonds are present in these functional groups:" and then you can find the additional sources in each of the functional group pages. There is no need to duplicate references, takes a lot of administrative overhead.
 * the periodic table on display is central to more than 50 pages and has been visible unopposed for several years, you may want to seek wider consensus here before making this move

Redid the lede separating out
…the data rich EN and bond length material into its own section. In expanding, I added C=O to the only mentioned C-O, and gave examples. See how this fits. Le Prof

Bond-order problem
The table in lists bond orders. The values are a mix of direct Lewis structure analysis and resonance effects. For example, acids, esters, and carbonates are by appearance regular single and double bonds, with bond orders as given (1 and 2, respecgively). But actually they are fractional values due to resonance from the "single"-bonded O towards the "carbonyl", making their values a little more than 1 and a little less than 2, respectively. In the furan and pyrylium cases, the values are indeed fractional due to ring resonance. But for furan there's no way 1.5 is correct—5 edges times 1.5 B.O. is 7. pairs; with six sigma pairs, that leaves 1.5 pi pairs! It should actually be 3 pairs (2 "alkene" + 1 "O lone-pair" in simple Lewis terms). At least for pyrylium, 6&times;1.5=9 pairs, –6 sigma leaves 3 pi which is correct. But in neither ring case is the ring a regular polygon, so even if these were average bond orders, different edges would vary. DMacks (talk) 05:22, 26 February 2019 (UTC)