The donor atoms of the base are highlighted with underline
Hard acid
Small cations, not easily to polarized, high charged, low electronegativity for a metal
Hard base
Halides, oxoanions (high charge/oxidation state), ionic bonding dominant, very high electronegativity, small sized donor atom
Interaction between hard acid/base
Predominantly coulombic, ionic, dipole-dipole and electrostatic
Dipole–dipole interactions are electrostatic interactions between molecules which have permanent dipoles - partial charged (e.g., HCl-HCl)
Soft acid
Larger cations, easily to polarize, low charge, intermediate to high electronegativity
Electric polarizability is the relative tendency of a charge distribution, like the electron cloud of an atom or molecule, to be distorted from its normal shape by an external electric field
Soft base
Large size, intermediate to high electronegativity
