News tagged with molecules

Related topics: cells · protein · atoms · cancer cells · cancer

A simpler way to treat cancer

(Medical Xpress)—Sometimes the best solutions are the simplest ones. This is the philosophy that Northeastern professor Vladimir Torchilin and his team took in new research carried out in collaboration with physics professor ...

Jun 02, 2014
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Drug therapy for allergy moves forward

Researchers have identified several target molecules which are suitable for the development of new allergy drugs. The Journal of Allergy and Clinical Immunology, the most prestigious journal in the field of allergology, has ...

May 12, 2014
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Unlocking a mystery of thalidomide

In the 1950s and 1960s, pregnant women with morning sickness were often prescribed the new drug thalidomide. Shortly after the medicine was released on the market, a reported 10,000 infants were born with an extreme form ...

May 01, 2014
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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.

This text uses material from Wikipedia, licensed under CC BY-SA

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