Noun
lone pair (plural lone pairs)
(chemistry) A pair of electrons in the valence shell of an atom that does not participate in bonding.
We may say that a basic substance is one which has a lone pair of electrons which may be used to complete the stable group of another atom, and that an acid is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Gilbert N. Lewis
Chirality main Amines of the type NHRR′ and NRR′R″ are chiral : the nitrogen atom bears four substituents counting the lone pair. Source: Internet
Figure 1: Dehydration synthesis (condensation) reaction forming an amide Cis/trans isomers of the peptide group Significant delocalisation of the lone pair of electrons on the nitrogen atom gives the group a partial double bond character. Source: Internet
As a result, the lone pair does not contribute to the aromatic system but importantly influences the chemical properties of pyridine, as it easily supports bond formation via an electrophilic attack. Source: Internet
One lone pair is used as a sigma X donor, the other two lone pairs are available as L-type pi donors. Source: Internet
For example, hydrogen fluoride—which has three lone pairs on the F atom but only one H atom—can form only two bonds; ( ammonia has the opposite problem: three hydrogen atoms but only one lone pair). Source: Internet