ion Meaning, Definition & Usage

noun a particle that is electrically charged (positive or negative); an atom or molecule or group that has lost or gained one or more electrons

Gr. , neut, of , p. pr. of to go.

(Elec. Chem.) One of the elements which appear at the respective poles when a body is subjected to electro-chemical decomposition. Cf. Anion, Cation. an atom or goup of atoms (radical) carrying an electrical charge. Contrasted with neutral atoms or molecules, and free radicals. Certain compounds, such as sodium chloride, are composed of complementary ions in the solid (crystalline) as well as in solution. Others, notable acids such as hydrogen chloride, may occur as neutral molecules in the pure liquid or gas forms, and ionize almost completely in dilute aqueous solutions. In solutions (as in water) ions are frequently bound non-covalently with the molecules of solvent, and in that case are said to be solvated.