Molecule

A molecule is the smallest particle of a pure chemical substance that still retains its chemical composition and properties. The science of molecules is called molecular chemistry or molecular physics, depending on the particular aspect of focus. Molecular chemistry is concerned with the laws governing the interaction between molecules that results in the formation and breakage of chemical bonds, while molecular physics is concerned with the laws governing their structure and properties. In practice, however, this distinction is rather vague.

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According to the strict definition, molecules can consist of one atom (as in noble gases) or more atoms bonded together. The concept of monatomic (single-atom) molecule is used almost exclusively in the kinetic theory of gases. In molecular sciences a molecule consists of a stable system (bound state) comprising two or more atoms. The term unstable molecule is used for very reactive species, i.e. short-lived assemblies (resonances) of electrons and nuclei, such as radicals, molecular ions, Rydberg molecules (see Rydberg atoms), transition states, Van der Waals complexes, or systems of colliding atoms as in Bose-Einstein condensates. A peculiar use of the term molecular is as a synonym to covalent, which arises from the fact that, unlike covalent compounds, ionic compounds do not yield well-defined smallest particles that would be consistent with the definition above.

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Although the concept of molecule was first introduced in 1811 by Avogadro, the existence of molecules was still an open debate in the chemistry community until the work of Perrin (1911). The modern theory of molecules makes great use of the many numerical techniques offered by computational chemistry.

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For a list of molecules see the List of compounds.

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Particle: A particle is...

Chemical substance: A chemical substance is any material substance used in or obtained by a process in chemistry:...

Chemical composition: The chemical composition of a substance refers to the elements of which the substance is composed. For example, common table salt is composed of sodium and chlorine, but this familiar chemical compound is also found in halite....

Molecule related Images and Photos (experimental)

Ethanol Molecule	Caffeine Molecule	Capsaicin Molecule	Ethanol Molecule Flask
Caffeine Molecule Necklace	Capsaicin Molecule Babydoll	Chocolate Molecule Babydoll	Capsaicin Molecule Babydoll
Capsaicin Molecule Babydoll	Capsaicin Molecule Babydoll	Caffeine Molecule Stainless Travel Mug	Chocolate Molecule Women's Classic Cut