What does nonionic mean?
Nonionic describes a substance, particle, or interaction that is not ionic, meaning it does not consist of electrically charged particles called ions. The term is especially common in chemistry and in the description of nonionic surfactants, detergents whose molecules have no net electrical charge. Nonionic does not mean that a substance has no electrical properties; it means that it does not carry a charge or behave as an ion. In laboratory and industrial contexts, the contrast is often with ionic compounds or materials, whose charged nature can affect solubility, conductivity, and interactions with other substances. The word is most often encountered in technical and scientific writing, including discussions of emulsions, cleaning products, biological membranes, and chemical interfaces. Outside specialist contexts, it may be unfamiliar, but it provides a precise way of distinguishing electrically neutral molecules or materials from charged ones.
adjectiveDenoting a substance, particle, or interaction that does not carry an electric charge and is not composed of ions.
- Not ionic; not consisting of, or involving, electrically charged particles called ions.
"The detergent contains several nonionic surfactants that help loosen grease from fabrics."
"The researchers compared the behaviour of ionic and nonionic surfactants in the emulsion."
"Only the nonionic compounds remained dispersed after the solution was exposed to a strong electric field."
Nonionic does not mean non-electrical: a nonionic substance may still influence electrical behaviour without carrying a net charge.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of nonionic
Nonionic was formed in English by combining the prefix non- with ionic. Ionic ultimately comes from ion, which was borrowed from Greek ion, meaning 'going' and referring to particles 'going' or moving in an electric field. The prefix non- gives the word its modern technical meaning: 'not ionic.'
Related word forms
How nonionic is actually used
This is primarily a technical term used in chemistry, biochemistry, and related fields. It is especially common in the term 'nonionic surfactant', where it distinguishes surfactants that do not carry an electrical charge.