Ice is believed to have played a crucial role in the emergence of life. One reason is that organic molecules can be excluded into the gaps between the crystal lattice by orderly arranged water molecules, leading to the concentration ...
Biochemistry
3 hours ago
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1
A research team led by Osaka University discovered that the new organic molecule thienyl diketone shows high-efficiency phosphorescence. It achieved phosphorescence that is more than ten times faster than traditional materials, ...
Analytical Chemistry
Jul 4, 2024
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47
Versatile molecular frameworks called discrete supramolecular structures act like microscopic building blocks customizable for a wide variety of applications. The structures can serve in drug delivery, provide unique environments ...
Analytical Chemistry
Jul 2, 2024
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Despite gaining a bad rap in mainstream media in recent years, nanoparticles have been successfully used for decades in targeted drug delivery systems. Drug molecules can be encapsulated within biodegradable nanoparticles ...
Bio & Medicine
Jun 27, 2024
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73
The University of Antwerp and CIC biomaGUNE have come up with a promising method for understanding the role of surface molecules in the formation of nanoparticles. The groundbreaking research, published in Nature Chemistry, ...
Nanomaterials
Jun 27, 2024
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68
A research group led by Dr. Edward Curtis has developed two new types of catalytic DNA molecules (deoxyribozymes) that can reveal the presence of target molecules through fluorescence or color. Several types of sensors were ...
Molecular & Computational biology
Jun 26, 2024
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Medical products such as ointments or syringes reach their limits when it comes to delivering medication locally—and above all in a controlled manner over a longer period of time. Empa researchers are therefore developing ...
Biochemistry
Jun 25, 2024
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Aniline or nitrogen-containing organic molecules like 3-aniline-substituted indoles commonly found in natural products have shown promising results as pharmaceutical contenders. The same goes for moieties such as 2-aminoaryl ...
Analytical Chemistry
Jun 24, 2024
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Chiral molecules—that is, those that have mirror images of themselves—have significant benefits for transistors and solar energy devices. Studying their properties in close detail, though, has been tricky due to the limited ...
Condensed Matter
Jun 24, 2024
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28
A novel technique with potential applications for fields such as droplet chemistry and photochemistry has been demonstrated by an Osaka Metropolitan University-led research group.
Optics & Photonics
Jun 24, 2024
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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.
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