Editing Lone pair (section)

==Stereogenic lone pairs==
{| align=right valign=center width="272px" style="margin-left:2em; margin-bottom:1ex"
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|[[File:Amine R-N.svg|56px]]
| style="font-size:200%" |⇌&nbsp;
|[[File:Amine N-R.svg|56px]]
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| colspan=3 |Inversion of a generic organic amine molecule at nitrogen
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A lone pair can contribute to the existence of chirality in a molecule, when three other groups attached to an atom all differ. The effect is seen in certain [[amine]]s, [[phosphine]]s,<ref>Quin, L. D. (2000). ''A Guide to Organophosphorus Chemistry,'' LOCATION: John Wiley & Sons. {{ISBN|0471318248}}.</ref> [[sulfonium]] and [[oxonium ion]]s, [[sulfoxide]]s, and even [[carbanion]]s.

The [[chiral resolution|resolution]] of enantiomers where the stereogenic center is an amine is usually precluded because the [[activation energy|energy barrier]] for [[nitrogen inversion]] at the stereo center is low, which allow the two stereoisomers to rapidly interconvert at room temperature. As a result, such chiral amines cannot be resolved, unless the amine's groups are constrained in a cyclic structure (such as in [[Tröger's base]]).
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