Ions as Isolated Particles

Ions are defined as particles that carry electrical charges. They may exist in gaseous phases as individual ions, but in condensed phases (solids and liquids), they exist as electrically neutral combinations of cations and anions, and in solutions they exist as electrolytes, the ions of which may be bound or relatively free to migrate. 

Ions in an ideal gaseous state, termed isolated or bare ions, are devoid of interactions with other particles or their surroundings and are commonly monatomic or consist of relatively few atoms. They may also be the centers of clusters consisting of the ion proper surrounded by a small number of solvent molecules. 

Ions in Solution and Their Solvation, First Edition. Yizhak Marcus. 

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