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
Wikipedia.
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News tagged with molecules
Using lasers to cool and manipulate molecules
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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 |
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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 ...
Newly explored bacteria reveal some huge RNA surprises
Dec 02, 2009 |
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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 ...
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.
Machine Converts CO2 into Gasoline, Diesel, and Jet Fuel
Nov 23, 2009 |
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(PhysOrg.com) -- Researchers at Sandia National Laboratories have built a machine that uses the sun's energy to convert carbon dioxide waste from power plants into transportation fuels such as gasoline, diesel, ...
A (nano-) window that washes itself?
Nanotechnology / Nanomaterials
Dec 03, 2009 |
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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 ...
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.
First Pump-Probe Experiment at Linac Coherent Light Source Completed
Nov 30, 2009 |
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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 ...
First live targeting of tumors with RNA-based technology
Nov 30, 2009 |
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(PhysOrg.com) -- Finding and treating a tumor without disturbing normal tissue presents challenges - sometimes the most effective therapies can be invasive and harsh.
Multiferroic compounds used to produce smaller and cheaper digital memories
Nov 27, 2009 |
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(PhysOrg.com) -- Is it possible to make even more compact digital memories for portable electronic devices and which consume even less energy? A team of French researchers has recently demonstrated that it ...
Researchers find explanation for rapid maturation of neurons at birth
Medicine & Health / Neuroscience
Nov 17, 2009 |
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At the moment a newborn switches from amniotic fluid to breathing air, another profound shift occurs: nerve cells in the brain convert from hyperexcitability to a calm frame against which outside signals can be detected.
Scientists guide immune cells with light and microparticles (w/ Video)
Nov 16, 2009 |
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A team led by Yale University scientists has developed a new approach to studying how immune cells chase down bacteria in our bodies. Their findings are described in the November 15 issue of Nature Methods Advanc ...
In touch with molecules
Nov 12, 2009 |
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The performance of modern electronics increases steadily on a fast pace thanks to the ongoing miniaturization of the utilized components. However, se-vere problems arise due to quantum-mechanical phenomena ...
Researchers show how to divide and conquer 'social network' of cells
Nov 09, 2009 |
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On Noah's Ark animals came in twos: male and female. In human bodies trillions of cells are coupled, too, and so are the molecules from which they are composed. Yet these don't come in twos, they are regrouped ...
Stick and slide: Computer simulation advances understanding of molecular motors
Dec 02, 2009 |
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A new study reveals how molecular motors that power important subcellular movements can generate cyclical motion. The research, published by Cell Press in the December issue of the Biophysical Journal, opens a new door t ...
