An ionic bond could be considered an extreme form of a covalent bond where the bond is so highly polarised by the two atoms that the electrons are completely localised onto one of the two atoms. This leaves an electron deficient positively charged cation and a negatively charged anion with an electron surplus.

However the concept of an actual ionic bond is somewhat of a misnomer as there is no one-to-one bonding between ions. Ionic solids are aggregations of ions that are electrostatically attracted to each other. When they are in solution the cations and anions of ionic solids are completely surrounded by the solvent.