Adsorbates

Part of speech: noun

Definitions

1. A substance that adheres to the surface of another material without penetrating it
2. Any molecular species that forms a layer on a solid or liquid surface
3. Compounds or particles that accumulate at the interface between phases, influencing surface properties

Etymology: Adsorbates are the substances that stick to a surface, and the word is built from a verb and a chemical suffix. Its first half, "adsorb," is formed from the Latin prefix "ad-," meaning "to" or "toward," joined to "sorb," meaning to soak up or take in. The contrast with absorption is the key: an adsorbed molecule clings to the outside of a solid or liquid rather than soaking into its interior. The second half, "-ate," comes from the Latin suffix "-atus," used to form nouns and adjectives from verb stems. In chemistry the suffix has a specific job, marking a substance that is the product or thing acted upon by a process, so "adsorbate" names the material being held onto, while the surface doing the holding is the "adsorbent." The plural "adsorbates" is simply the form used when several such substances are meant.