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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
Dec 20, 2009 |
4.4 / 5 (25) |
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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 ...
Molecular freight: Synthetic nanoscale transport system modeled on nature
Dec 21, 2009 |
4.4 / 5 (5) |
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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 ...
Tracing the traces: Nanogram concentrations of a toxic compound detected in chlorinated tap water
Chemistry / Analytical Chemistry
Dec 23, 2009 |
5 / 5 (4) |
6
(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 ...
Making New Enzymes to Engineer Plants for Biofuel Production
Dec 21, 2009 |
5 / 5 (1) |
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(PhysOrg.com) -- Brookhaven scientists have created a new enzyme with the potential to interfere with a key cell-wall component in plants, possibly leading to plants that are easier to "digest" and convert ...
Search results for molecules
Genomic toggle switches divide autoimmune diseases into distinct clusters
Dec 23, 2009 |
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0
Genomic switches can predispose an individual to one set of autoimmune disorders but protect the same person against another set of them, scientists at Stanford University School of Medicine have found.
A novel gene found for childhood-onset asthma
Dec 23, 2009 |
not rated yet |
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Pediatric researchers have identified a novel gene involved in childhood asthma, in one of the largest gene studies to date of the common respiratory disease. Because the gene, called DENND1B, affects cells and signaling ...
Genomic differences identified in common skin diseases
Dec 23, 2009 |
5 / 5 (2) |
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(PhysOrg.com) -- If you have dry skin, wet it, if wet skin, dry it. This has been a general rule of dermatology for centuries, but scientists are working to develop more precise treatments for the dozen-plus inflammatory ...
Scientists create world's first molecular transistor
Dec 23, 2009 |
4.9 / 5 (24) |
2
A group of scientists has succeeded in creating the first transistor made from a single molecule. The team, which includes researchers from Yale University and the Gwangju Institute of Science and Technology ...
An easy way to see the world's thinnest material
Nanotechnology / Nanomaterials
Dec 23, 2009 |
4.7 / 5 (10) |
1
It's been used to dye the Chicago River green on St. Patrick's Day. It's been used to find latent blood stains at crime scenes. And now researchers at Northwestern University have used it to examine the thinnest material ...
Shallow Origins
Space & Earth / Earth Sciences
Dec 22, 2009 |
5 / 5 (12) |
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In finding answers to the mystery of the origin of life, scientists may not have to dig too deep. New research is shedding light on shallower waters as a possible location for where life on Earth began.
Nanoscale changes in collagen are a tipoff to bone health
Dec 22, 2009 |
5 / 5 (1) |
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Using a technique that provides detailed images of nanoscale structures, researchers at the University of Michigan and Detroit's Henry Ford Hospital have discovered changes in the collagen component of bone ...
New insight in nerve cell communication
Medicine & Health / Neuroscience
Dec 22, 2009 |
4 / 5 (1) |
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Communication between nerve cells is vital for our bodies to function. Part of this communication happens through vesicles containing signalling molecules called neurotransmitters. The vesicle fuses with the ...
Mystery solved: Scientists now know how smallpox kills
Dec 22, 2009 |
5 / 5 (10) |
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A team of researchers working in a high containment laboratory at the Centers for Disease Control and Prevention in Atlanta, GA, have solved a fundamental mystery about smallpox that has puzzled scientists long after the ...
Researchers are on the path to creating nano-MRI images
Dec 22, 2009 |
4.7 / 5 (6) |
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(PhysOrg.com) -- Cornell researchers are devising methods to detect the magnetic fields of individual electrons and atomic nuclei, which they hope to use to make a nanoscale version of magnetic resonance imaging.
List of search results for molecules
