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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Molecular entity | 1/1 | https://en.wikipedia.org/wiki/Molecular_entity | reference | science, encyclopedia | 2026-05-05T11:28:34.461896+00:00 | kb-cron |
In chemistry and physics, a molecular entity, or chemical entity, is "any constitutionally or isotopically distinct atom, molecule, ion, ion pair, radical, radical ion, complex, conformer, etc., identifiable as a separately distinguishable entity". A molecular entity is any singular entity, irrespective of its nature, used to concisely express any type of chemical particle that can exemplify some process: for example, atoms, molecules, ions, etc. can all undergo a chemical reaction. Chemical species is the macroscopic equivalent of molecular entity and refers to sets or ensembles of molecular entities. According to IUPAC, "The degree of precision necessary to describe a molecular entity depends on the context. For example 'hydrogen molecule' is an adequate definition of a certain molecular entity for some purposes, whereas for others it is necessary to distinguish the electronic state and/or vibrational state and/or nuclear spin, etc. of the hydrogen molecule."
== See also == Amount of substance - a quantity proportional to the number of entities in a substance Mole (unit) - an aggregate of entities given by the Avogadro number New chemical entity Chemical Entities of Biological Interest Particle
== References ==