Lewis base

A Lewis base is a chemical entity that can donate a pair of electrons to another atom or molecule during a chemical reaction. Think of it as an electron-rich partner seeking to share its electrons with an electron-deficient partner, known as a Lewis acid. This electron donation helps form new chemical bonds. Examples include substances like ammonia (NH₃) or hydroxide ions (OH⁻), both of which have lone pairs of electrons available for bonding. Lewis bases are fundamental in many chemical processes, such as catalysis and biochemical reactions.