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Molecule
hideA 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.
For more information about Molecule, read the full article at
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News tagged with molecules
Faster, cheaper DNA sequencing method developed
Nanotechnology / Bio & Medicine
15 hours ago |
4.6 / 5 (16) |
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(PhysOrg.com) -- Boston University biomedical engineers have devised a method for making future genome sequencing faster and cheaper by dramatically reducing the amount of DNA required, thus eliminating the ...
Bourbon versus vodka: Bourbon hurts more the next day, performance is the same
Dec 18, 2009 |
3.7 / 5 (3) |
0
Many alcoholic beverages contain byproducts of the materials used in the fermenting process. These byproducts are called "congeners," complex organic molecules with toxic effects including acetone, acetaldehyde, fusel oil, ...
Heme channel found
Dec 17, 2009 |
not rated yet |
0
In some ways a cell in your body or an organelle in that cell is like an ancient walled town. Life inside either depends critically on the intelligence of the gatekeepers.
Caltech scientists film photons with electrons
Dec 16, 2009 |
4.9 / 5 (21) |
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(PhysOrg.com) -- Techniques recently invented by researchers at the California Institute of Technology -- which allow the real-time, real-space visualization of fleeting changes in the structure of nanoscale ...
Scientists isolate new antifreeze molecule in Alaska beetle
Dec 14, 2009 |
5 / 5 (14) |
4
Scientists have identified a novel antifreeze molecule in a freeze-tolerant Alaska beetle able to survive temperatures below minus 100 degrees Fahrenheit. Unlike all previously described biological antifreezes that contain ...
Prussian blue linked to the origin of life
Dec 14, 2009 |
4.7 / 5 (6) |
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A team of researchers from the Astrobiology Centre (INTA-CSIC) has shown that hydrogen cyanide, urea and other substances considered essential to the formation of the most basic biological molecules can be ...
Newly identified enzymes help plants sense elevated CO2 and could lead to water-wise crops
Dec 13, 2009 |
5 / 5 (3) |
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Biologists have identified plant enzymes that may help to engineer plants that take advantage of elevated carbon dioxide to use water more efficiently. The finding could help to engineer crops that take advantage of rising ...
New approach to emissions makes climate and air quality models more accurate, major study finds
Space & Earth / Earth Sciences
Dec 10, 2009 |
3.9 / 5 (7) |
1
It's no secret that the emissions leaving a car tailpipe or factory smokestack affect climate and air quality. Even trees release chemicals that influence the atmosphere. But until now, scientists have struggled to know where ...
Researchers uncover chemical basis for extra 'quality control' in protein production
Dec 09, 2009 |
5 / 5 (1) |
0
December 9, 2009 -Even small errors made by cells during protein production can have profound disease effects, and nature has developed ways to uncover these mistakes and correct them. Though in the case of one essential ...
Newly discovered mechanism allows cells to change state
Dec 09, 2009 |
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Cells are not static. They can transform themselves over time — but change can have dangerous implications. Benign cells, for example, can suddenly change into cancerous ones.
Sparkly Spiders and Photonic Fish
Dec 09, 2009 |
4.5 / 5 (2) |
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(PhysOrg.com) -- Scientists in Israel and the UK have uncovered the details of how certain fish and spiders create their iridescent scales and silvery skins.
Undergrad researchers lay groundwork for drug addiction remedy
Dec 08, 2009 |
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Sarah Steele and Langtian "Ren" Yuan were both self-admittedly inexperienced Duke freshmen in the spring of 2006. But then they followed helpful directions of an assistant chemistry professor, added their own patience and ...
Using lasers to cool and manipulate molecules
Dec 07, 2009 |
4.8 / 5 (13) |
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(PhysOrg.com) -- "For years, we have been using laser cooling to trap and manipulate atoms," David DeMille tells PhysOrg.com. "This has been very useful for both basic science and many applications. Recent ...
Scientists take theoretical research on 'nasty' molecule to next level
Dec 04, 2009 |
4.4 / 5 (12) |
3
(PhysOrg.com) -- Some atoms don't always follow the rules. Take the beryllium dimer, a seemingly simple molecule made up of two atoms that University of Delaware physicists Krzysztof Szalewicz and Konrad Patkowski ...
Diffusion tensor imaging increases ability to remove benign tumors in children
Medicine & Health / Neuroscience
Dec 04, 2009 |
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A new study published this week in the Journal of Neurosurgery: Pediatrics finds that operative plans for removing Juvenile Pilocytic Astrocytoma, or JPA, tumors in the thalamus of the brain can be augmented with Diffusion Tensor ...
