What is Lewis base

Atomic or molecular chemical species having a highly localized HOMO (Highest Occupied Molecular Orbital) act as Lewis bases. These chemical species have the ability to donate an electron pair to a given Lewis acid in order to form an adduct, as discussed earlier.

The most common Lewis bases are ammonia, alkyl amines, and other conventional amines. Commonly, Lewis bases are anionic in nature and their base strength generally depends on the pKa of the corresponding parent acid.

Examples of Lewis Bases

Examples of Lewis bases which have an ability to donate an electron pair are listed below.

• Pyridine and the derivatives of pyridine have the ability to act as electron pair donors.
• The compounds in which Oxygen, Sulfur, Selenium, and Tellurium (which belong to group 16 of the Periodic Table) exhibit an oxidation state of -2 are generally Lewis bases. Examples of such compounds include water and ketones.