What are hard base and soft base?

Metal–ligand interaction is an example of a Lewis acid–base interaction. Lewis bases can be divided into two categories: hard bases contain small, relatively nonpolarizable donor atoms (such as N, O, and F), and; soft bases contain larger, relatively polarizable donor atoms (such as P, S, and Cl). read more

hard bases contain small, relatively nonpolarizable donor atoms (such as N, O, and F), and; soft bases contain larger, relatively polarizable donor atoms (such as P, S, and Cl). Metal ions with the highest affinities for hard bases are hard acids, whereas metal ions with the highest affinity for soft bases are soft acids. read more

HSAB concept is an initialism for"hard and soft (Lewis) acids and bases". Also known as the Pearson acid base concept, HSAB is widely used in chemistry for explaining stability of compounds, reaction mechanisms and pathways. It assigns the terms 'hard' or 'soft', and 'acid' or 'base' to chemical species. read more