Related topics: atoms , protein , proceedings of the national academy of sciences , cells , genes
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
Innovation puts next-generation solar cells on the horizon
Dec 01, 2009 |
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In a world first, a Monash University-led international research team has developed an innovative way to boost the output of the next generation of solar cells.
Faster, cheaper DNA sequencing method developed
Nanotechnology / Bio & Medicine
Dec 20, 2009 |
4.4 / 5 (27) |
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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 ...
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) |
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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 ...
Using lasers to cool and manipulate molecules
Dec 07, 2009 |
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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 ...
Newly explored bacteria reveal some huge RNA surprises
Dec 02, 2009 |
4.9 / 5 (12) |
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(PhysOrg.com) -- Yale University researchers have found very large RNA structures within previously unstudied bacteria that appear crucial to basic biological functions such as helping viruses infect cells ...
First Pump-Probe Experiment at Linac Coherent Light Source Completed
Nov 30, 2009 |
4.7 / 5 (12) |
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(PhysOrg.com) -- The first experiment using the Linac Coherent Light Source to illuminate molecules via a "pump-probe" technique has been completed by an international team of more than 30 scientists from ...
Scientists take theoretical research on 'nasty' molecule to next level
Dec 04, 2009 |
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(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 ...
A (nano-) window that washes itself?
Nanotechnology / Nanomaterials
Dec 03, 2009 |
4.5 / 5 (8) |
9
A coating on windows or solar panels that repels grime and dirt? Expanded battery storage capacities for the next electric car? New Tel Aviv University research, just published in Nature Nanotechnology, detail ...
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 ...
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) |
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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 ...
Tracing the traces: Nanogram concentrations of a toxic compound detected in chlorinated tap water
Chemistry / Analytical Chemistry
Dec 23, 2009 |
5 / 5 (5) |
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(PhysOrg.com) -- Drinking water can transmit a number of diseases, including typhoid, dysentery, cholera, and diarrhea, which can then spread explosively throughout an entire service area. To avoid this problem, drinking ...
Molecular freight: Synthetic nanoscale transport system modeled on nature
Dec 21, 2009 |
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(PhysOrg.com) -- Just like our roads, there is a lot of traffic within the cells in our bodies, because cell components, messenger molecules, and enzymes must also be brought to the right places in the cell. One of these ...
Newly identified enzymes help plants sense elevated CO2 and could lead to water-wise crops
Dec 13, 2009 |
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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 ...
Grooving down the helix: Researchers show how proteins slide along DNA to carry out vital biological processes
Dec 03, 2009 |
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(PhysOrg.com) -- A team of scientists has made a major step in understanding how molecules locate the genetic information in DNA that is necessary to carry out important biological processes.
