A chemical species that accepts an electron pair is classified as a Lewis acid, while a Lewis base donates an electron pair. This classification broadens the scope of acid-base chemistry beyond the traditional definitions centered on proton transfer. For example, boron trifluoride (BF3), despite lacking a transferable proton, readily accepts an electron pair from ammonia (NH3), acting as a Lewis acid.
The significance of electron-pair acceptance and donation as the basis for acid-base interactions lies in its ability to explain a wider range of chemical reactions. This framework is particularly valuable in understanding reactions involving transition metals and coordination complexes, where proton transfer is not always the primary mechanism. This definition expanded the understanding of catalytic processes and inorganic chemistry significantly.
