Comments on: What Makes A Good Nucleophile?

By: James Ashenhurst

James Ashenhurst — Tue, 10 Mar 2026 13:48:54 +0000

In reply to Tai. PPh3 vs (-)SR is not directly comparable since sulfur bears a negative charge. A better comparison is R-S-R vs PPh3 where P is superior. The conjugate base is always a better nucleophile than the parent compound.

By: Tai

Tai — Mon, 09 Mar 2026 01:50:12 +0000

Hi! I thought phosphorus would be a better nucleophile than sulfur due to the fact that it’s less electronegative. They have similar polarized ability because they are in the same row on the periodic table, but phosphorus is less electronegative. Also, would this fact change if the atoms are carrying a negative charge?

By: James Ashenhurst

James Ashenhurst — Sat, 21 Feb 2026 09:32:59 +0000

In reply to Dr Harsha. They are essentially the same. Perhaps methoxide is slightly more nucleophilic because it is slightly more basic.

By: Dr Harsha

Dr Harsha — Tue, 17 Feb 2026 08:51:33 +0000

Which one is stronger nucleophile among methoxide ion and hydroxide ion?

By: Rohan Khan

Rohan Khan — Tue, 22 Sep 2020 09:23:36 +0000

Dear Sir.
You are the best.
I love the way in which you explain these terms in correct order and sequence….starting from the very basic terms.
You have cleared, all my confusion.
Everyone can easily understand,as you have explained in very proper manner.

By: James Ashenhurst

James Ashenhurst — Thu, 21 Nov 2019 21:41:09 +0000

In reply to Raj. Cyanide ion is more nucleophilic, and the lone pair that is transferred is the carbon. Otherwise the result would have a positively charged nitrogen and a negatively charged carbon.

By: Raj

Raj — Thu, 21 Nov 2019 19:07:29 +0000

This was life saving for me!
But, tell me which one has more nucleophilicity CN(-) or OH(-)…and which electron pair is actually transferred in CN(-)..that of carbon or nitrogen?

By: James Ashenhurst

James Ashenhurst — Wed, 18 Sep 2019 20:55:46 +0000

In reply to karthika. I think you mean hydride source? The isopropyl C-H bond is weaker.

By: James Ashenhurst

James Ashenhurst — Wed, 18 Sep 2019 16:15:23 +0000

In reply to Hosni Elwan. Hydroxide ion - it is a stronger base.

By: James Ashenhurst

James Ashenhurst — Fri, 13 Sep 2019 17:08:53 +0000

In reply to AAKASH. Which will be a stronger base? Can you find a pKa table to give you the values for H2O and CH3OH? That will tell you which will be a stronger base, since the weaker the acid, the stronger the conjugate base.