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A possible strategy for a tabletop chiral attosecond laser

When molecules form from many atoms, the atoms can combine in different ways. Two forms of the same molecule can have the same composition but have different arrangements of atoms, giving rise to isomers. Some isomers may ...

Rabi oscillations in a stretching molecule

Over eighty years ago, Rabi oscillations were proposed to describe the strong coupling and population transfer in a two-level quantum system exposed to an oscillatory driving field. As compared to atoms, molecules have an ...

Robots and AI team up to discover highly selective catalysts

Researchers used a chemical synthesis robot and computationally cost-effective AI model to successfully predict and validate highly selective catalysts. Their results are published in the journal Angewandte Chemie International ...

This one-atom chemical reaction could transform drug discovery

Pharmaceutical synthesis is often quite complex; simplifications are needed to speed up the initial phase of drug development and lower the cost of generic production. Now, in a study recently published in Science, researchers ...

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Molecule

A molecule is defined as a sufficiently stable, electrically neutral group of at least two atoms in a definite arrangement held together by very strong (covalent) chemical bonds. Molecules are distinguished from polyatomic ions in this strict sense. In organic chemistry and biochemistry, the term molecule is used less strictly and also is applied to charged organic molecules and biomolecules.

In the kinetic theory of gases the term molecule is often used for any gaseous particle regardless of its composition. According to this definition noble gas atoms are considered molecules despite the fact that they are composed of a single non-bonded atom.

A molecule may consist of atoms of a single chemical element, as with oxygen (O2), or of different elements, as with water (H2O). Atoms and complexes connected by non-covalent bonds such as hydrogen bonds or ionic bonds are generally not considered single molecules.

No typical molecule can be defined for ionic crystals (salts) and covalent crystals (network solids), although these are often composed of repeating unit cells that extend either in a plane (such as in graphene) or three-dimensionally (such as in diamond or sodium chloride). The theme of repeated unit-cellular-structure also holds for most condensed phases with metallic bonding. In glasses (solids that exist in a vitreous disordered state), atoms may also be held together by chemical bonds without any definable molecule, but also without any of the regularity of repeating units that characterises crystals.

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