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Taming of a shape-shifter molecule

Shape-shifter molecules are in never-ending motion. Their structure fluctuates because the carbon bonds that hold them together constantly break up and form again. Researchers have now found a way to "tame" a shape-shifter ...

How deep-sea worms help keep natural gases on ice

It is well known that natural gas hydrates, crystalline lattices of hydrogen-bonded water molecules that encapsulate small hydrocarbon molecules, on the ocean floors constitute both a potential accelerator of climate change ...

Genome research: Finding the invisible

LMU researchers have developed a method to extract more information from sequencing data. This will afford deeper insights into biology.

Increasing efficiency in artificial photosynthesis

Chemical engineers at EPFL have developed a new approach to artificial photosynthesis, a method for harvesting solar energy that produces hydrogen as a clean fuel from water.

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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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