ioniques

Ionique, or ioniques in plural form, is a term encountered in chemistry to describe substances or processes related to ions. In English-language usage, the corresponding concept is typically called ionic, and the plural form ioniques is rarely used outside of francophone scientific writing. The term broadly covers ionic compounds, ionic liquids, and other ion-based materials or phenomena.

Ionic compounds are composed of positively charged cations and negatively charged anions held together by electrostatic forces in a crystal lattice. They usually have high melting points, are brittle as solids, and conduct electricity when melted or dissolved in water. Ionic liquids are salts that are liquid at or near room temperature; they feature low vapor pressure, wide electrochemical windows, and high thermal stability, making them useful as solvents and electrolytes in various chemical processes.

In addition to salts and ionic liquids, ionique contexts include ion-exchange materials, where ions are swapped between a solid phase and a solution, enabling water softening and purification; and ionically conducting polymers used in sensors, batteries, and electrochromic devices. The properties of ioniques—such as ionic mobility, lattice energy, and hydration—govern their behavior in solution, melting, conductivity, and reactivity.

While the term ioniques appears in some multilingual sources, most English-language discussions prefer “ionic” or specify the subclass (ionic compound, ionic liquid, ion-exchange resin). See also ion, ionization, ionic compound, ionic liquid, and electrochemistry.