Talk:Double bond rule

Another "double bond rule" in organic chemistry

I found this quote "Otto Schmidt recognized the same bond weakening effect in hydrocarbons and in 1932 postulated the "Double-Bond Rule," stating that the presence of a double bond in a hydrocarbon has an alternating strengthening and weakening effect on single bonds throughout the molecule, diminishing with distance from the double bond." in this paper A History of the Double-Bond Rule, Bernard E. Hoogenboom, J. Chem. Educ., 1998, 75 (5), p 596, DOI: 10.1021/ed075p596. New to me but this rule probably predates the one described in the article which is by the far the best known. May be worthy of a mention Axiosaurus (talk) 20:02, 17 February 2013 (UTC)

That is a rare find. There is all sorts of interesting stuff tucked away in J Chem Ed.

To me the double bond rule is a curious one because it is untrue for the most part. Its inclusion here is more of a historical marker. At one time we were taught thats double bonds between P's or Si's and, worse, heavier elements are unstable with respect to dimerization or such. But thermodynamically even simple alkenes spontaneously polymerize, the proviso being ceiling temperature. The with the crystallization of the diselenenes and RP=PR, talk of the double bond rule has subsided, it seems. Thinking about this rule, the only place it works is nitrogen, were RN=NR is more stable than the rings or polymer. But saying so in the article would be OR. --Smokefoot (talk) 20:21, 17 February 2013 (UTC)

• thanks for this info , I will try to include it in the article.V8rik (talk) 22:06, 19 February 2013 (UTC)

I have incorporated this second double bond rule in the article. V8rik (talk) 16:02, 16 April 2013 (UTC)

Sort by oxidation state in the case of S and P

The table is useful. One possible refinement would be sort some entries by oxidation state. e.g. S(II)=NR vs S(IV)=NR vs S(VI)=NR. Similar considerations could be applied to P(III) vs P(V). --Smokefoot (talk) 13:55, 20 March 2013 (UTC)

Is this an error???

"... elements with a principal quantum number greater than 2 for their valence electrons (period 3 elements and lower) ..." Shouldn't that be "period 3 elements and HIGHER"? Or am I misunderstanding something? But it seems to me that, if "lower" is correct, then it should also say "quantum number LESS than 2." Uporządnicki (talk) 19:11, 31 January 2022 (UTC)

Indeed. Fixed. DMacks (talk) 21:37, 17 September 2022 (UTC)

And incredibly, you fixed it JUST while I was looking at it again for the first time since I posted that question 8 months ago. Uporządnicki (talk) 22:16, 17 September 2022 (UTC)