Comments on: Orbital Hybridization And Bond Strengths

By: Deepti

Deepti — Wed, 29 May 2024 17:02:50 +0000

Thank you. I would also like to say this is a great website.. I really liked the explanations and the dash of humour in between :)

By: James Ashenhurst

James Ashenhurst — Tue, 05 Sep 2023 18:42:14 +0000

In reply to Deepti.

No C-H bonds broke. The C-Cl bond broke. The unhybridized p orbital used to be the sp3-hybridized C-Cl bond.

Imagine bonds as being tiny springs that attach atoms together – the C-Cl bond is always vibrating back and forth. Then imagine a vibration where the C-Cl bond becomes so long that the Cl- is able to break free, leaving with a pair of electrons. An empty orbital will remain, and the three filled C-H sp3 bonding pairs will adopt a geometry where they are slightly further apart (120°)

By: Deepti

Deepti — Tue, 05 Sep 2023 08:26:57 +0000

How did the sp3 hybridization of C in CH3Cl change to sp2 hybridization in CH3+ obtained after heterolytic cleavage?
CH3Cl –> CH3+ + Cl-
How is there suddenly an unhybridised p orbital present on C of CH3+ (perpendicular to the molecular plane) and the C-H bond angles are 120°.
Did C-H bonds break when sp3 hybridization changed to sp2?

By: James Ashenhurst

James Ashenhurst — Fri, 24 Feb 2023 17:39:23 +0000

In reply to Ayush sharma. No - nitrogen, oxygen, sulfur, other atoms exhibit orbital hybridization

By: Ayush sharma

Ayush sharma — Fri, 24 Feb 2023 16:13:43 +0000

is hybridisation limited to carbon only?

By: Duff

Duff — Wed, 05 May 2021 01:55:44 +0000

In part 7 you asked which product was most stable but your discussion dealt with the reaction and every point you made was sensible. The sp3 orbital in the (B) reaction would lend itself to a more favorable reaction in comparison to the sp orbital in the (A) reaction. My problem is, and maybe I’m overthinking this from a lot of experience with phenyl ethynyl endcaps and fluorinated cyclic olefins, wouldn’t the electron rich triple bond tend to lend electrons across the molecule to de-localize the carbocation thus making the methylacetylene product more stable. Victor made a good point about how messing with triple bonds can lead to quick reactions/polymerizations. I know the answer wouldn’t be as troublesome with just acetylene but in my addled mind the methyl group muddies up the result. Or I’m throwing arrows around willy-nilly like I did decades ago in school. Also, this site is amazing.

By: James Ashenhurst

James Ashenhurst — Mon, 03 May 2021 19:02:54 +0000

In reply to nigatu amsalu. Yes, that is correct.

By: nigatu amsalu

nigatu amsalu — Tue, 27 Apr 2021 12:24:58 +0000

thank you it is good post
can I use bond dissociation energy and bond energy interachegeablly ?

By: zazai

zazai — Mon, 30 Mar 2020 05:24:13 +0000

which sigma bond is strongest
A – s_s overlap
B – s-p overlap
C – p-p overlap

By: George

George — Wed, 04 Mar 2020 20:32:05 +0000

Jim, I tried posting a comment twice. I carefully copy and paste and read it in this box just to check it is OK. But each time some of my comment gets deleted after it is sent and it reads horrible. Ugh! Why?!? Third time lucky (probably not)
Jim,

First, thank you for your excellent posts (and figures!) which clarify so many points.

My question concerns the second part of your post. I have no trouble understanding that in an acid/base reaction an electron pair would prefer to sit in an orbital with more s character rather than one with more p.

But I guess my question is when you say think of alkane/alkyne acid base properties as similar to electronegativity across a row, the alternative might be to think of going up a column, where smaller, more electronegative atoms are worse acids (HF<< HCl < HBr < HI).

So wouldn't a C-H bond with more s character also stabilize the bond better? Consistent with this C-H bonds do decrease slightly in length from alkanes to alkynes.

Now obviously the experimental numbers support your way of thinking… but is there any chemical intuition you would use to explain why one should immediately think of this as going across a row rather than up a column?

The best I can come up with is, well the changes in size here are very modest as you move from alkanes to alkynes and more in line with going across a row, i.e. from carbon to fluorine covalent radii go: 84 pm to 57 pm, a difference of only 50%, while going up a column, iodine to fluorine size goes from 139 to 57 pm, a 144% difference (and the shell number changes).

Is there any other intuition you might offer of why electronegativity defeats the column size argument here?

Sorry for the length… and again… thank you for your wonderful site.

Regards,

George