Why can the enantiomers of a quaternary ammonium salt () be physically resolved into stable optical — Amines Chemistry Question

💡 Solution & Explanation

Simple chiral tertiary amines undergo rapid nitrogen inversion (umbrella effect) via a planar transition state, which requires a lone pair. Quaternary ammonium salts have four distinct groups bonded to nitrogen and lack a lone pair, fixing their tetrahedral geometry and preventing racemization.