New photocatalytic COFs mimic photosynthesis for H₂O₂ production

National University of Singapore (NUS) chemists have developed hexavalent photocatalytic covalent organic frameworks (COFs) which mimic natural photosynthesis for the production of hydrogen peroxide (H2O2), an important industrial ...

A new and simple method for super-resolution microscopy

MINFLUX is a powerful microscopy technique that allows researchers to see objects much smaller than the wavelength of light. A newly developed evolution of the process uses a simpler device to create the light pattern needed ...

Switching nanomagnets using infrared lasers

When molecules are irradiated with infrared light, they begin to vibrate due to the energy supply. For Andreas Hauser from the Institute of Experimental Physics at Graz University of Technology (TU Graz), this well-known ...

Untapped power: Logical operations using RNA droplets

RNA droplets can now be used to perform logical operations that take microRNA sequences as inputs, report scientists from Tokyo Tech. By self-assembling into network-like structures, RNA molecules form liquid-state droplets. ...

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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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