Comments on: Evaluating Resonance Structures With Positive Charge

By: James Ashenhurst

James Ashenhurst — Mon, 06 Mar 2023 22:14:52 +0000

In reply to uday. Yes, you've described the resonance form of a pi bond!

By: uday

uday — Sun, 05 Mar 2023 12:34:10 +0000

can resonance occur between lone pair with positive charge with single sigma bond between?

By: B.S.

B.S. — Sun, 04 Jul 2021 15:30:45 +0000

Teacher,
I do not hail from the US or from anywhere in the entire American continent, but I have found this site extremely helpful. Albeit our teacher claims that he is one of the best chemistry teachers, till now I had never been clarified that bond dissociation enthalpy is associated with homolytic cleavage. I wish I had known about this website earlier.

For your support, Thank You !

Happy Fourth !

By: james

james — Sat, 17 Dec 2011 20:04:02 +0000

In reply to marcus. Dude, you need to get hooked up with Chemdraw. The "convert structure to name" function will help (almost) all nomenclature questions.

By: james

james — Sat, 17 Dec 2011 20:03:01 +0000

In reply to jess.

*Great* point. This is a case where a tertiary carbocation would be less stable – you’d have it adjacent to an electron withdrawing group.
There’s always exceptions, aren’t there?

By: jess

jess — Thu, 15 Dec 2011 16:25:03 +0000

In reply to satyajit chakraborty.

Then again… suppose instead of N or S you had a carbonyl or CF3… by the definition you *would* have a tertiary carbocation. Unless tertiary means that the carbon in question is connected to three *alkyl* groups…

(Obviously, my o-chem instructor wasn’t very clear on this point…)

By: jess

jess — Thu, 15 Dec 2011 12:42:25 +0000

In reply to satyajit chakraborty. Thanks, I got it (eventually). A bad case of my reply-button-clicking-finger working faster than my brain.

By: marcus

marcus — Thu, 15 Dec 2011 11:09:37 +0000

Just in case anyone wants the name of the compound in the lower left of the last figure it’s N,N,N-trimethylcyclohex-1-enaminium. Just thought you all would like to know that as it took me several hours to find out it’s name and I must give all the credit to an anonymous person at another chemistry related board.

By: satyajit chakraborty

satyajit chakraborty — Thu, 15 Dec 2011 04:13:24 +0000

In reply to jess. ok,jess.the dfinition of tertiary carbocation is that the carbocation should be attatched directly to three actual carbons.look carefully that in these cases they are actually secondary as the third atom is actually not carbon but nitrogen or sulphur.

By: dr klbajaj

dr klbajaj — Thu, 15 Dec 2011 01:17:31 +0000

In a simple way if there is more valency in case of N o F put +chargeand in case of C if valency is less than normal put+ charge. Any charge in the molecule is undesireable.Any factor which increases the charge destabiles the molecule and vice verse.Resonance,presence of double bond,hetero atom having lone pair of electron will stabilise.Redice the charge either by resonance or by inductive effect