Chapter 3 Acid-base reactions in Klein's Organic Chemistry As a Second Language explains an exception to the typical order of important factors for determining how stable a negative charge on a conjugate base is [1, p. 61]:
This example illustrates that a negative charge on an $\mathrm{sp}$ hybridized carbon atom is more stable than a negative charge on an $\mathrm{sp^3}$ hybridized nitrogen atom. For this reason, $\ce{NH2-}$ can be used as a base to deprotonate a triple bond.
How specific is this exception? Does it only hold true for nitrogen? Or could an oxygen atom be $\mathrm{sp^3}$ or $\mathrm{sp^2}$ hybridized and still be less stable than the structure on the left despite its higher electronegativity?
Reference
- Klein, D. R. Organic Chemistry As a Second Language: First Semester Topics, 4th ed.; Wiley: Hoboken, 2016. ISBN 978-1-119-11066-8.