How is a Lewis base defined?

A Lewis base is defined as a substance that donates a pair of electrons to form a covalent bond. This definition highlights the role of electron pairs in chemical reactions, specifically in the context of Lewis acid-base theory, which expands on classic definitions by focusing on electron interactions rather than proton transfer.

In this framework, the Lewis base provides a pair of electrons to a Lewis acid, which is an electron acceptor. This interaction is fundamental in many chemical processes, including complex formation, catalysis, and organic reactions. Understanding Lewis bases in terms of electron pair donation is crucial for predicting and explaining the behavior of molecules in various chemical contexts. This clarification contrasts with definitions focused on protons, as Lewis acid-base theory is not limited to reactions involving hydrogen ions but encompasses a wider range of electron transfer processes.