How did life come about? The answer to this question goes to the very heart of our existence on planet Earth.
Astrobiology
Mar 25, 2023
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48
A Cranfield University designed instrument capable of remotely analyzing molecules from the air in Antarctica will help scientists understand future changes in our climate.
Environment
Mar 24, 2023
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23
A team of researchers have used a computational method inspired by evolution to discover an organic catalyst with better performance than known catalysts. As the team reports in the journal Angewandte Chemie International ...
Biochemistry
Mar 23, 2023
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41
Plants produce all types of curious chemicals. Some deter predators. Some smell wonderful. Some even have medicinal value. One of these hidden gems is (–)-jerantinine A (JA), a molecule with remarkable anticancer properties, ...
Biochemistry
Mar 23, 2023
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26
UC Riverside scientists have significantly advanced the race to control plant responses to temperature on a rapidly warming planet. Key to this breakthrough is miRNA, a molecule nearly 200,000 times smaller than the width ...
Plants & Animals
Mar 23, 2023
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61
The medicinal secrets of the Chilean soapbark tree have been laid bare, unlocking a future of more potent, affordable, and sustainably sought vaccines.
Biochemistry
Mar 23, 2023
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20
Researchers have analyzed samples of the asteroid Ryugu collected by the Japanese Space Agency's Hayabusa2 spacecraft and found uracil, one of the informational units that make up RNA, the molecules that contain the instructions ...
Astrobiology
Mar 21, 2023
2
409
The virus responsible for E. coli infection has a secret weapon: teamwork.
Analytical Chemistry
Mar 21, 2023
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72
Researchers from Tokyo Metropolitan University have found that gold nanoparticles supported on a zirconium oxide surface help turn waste materials like biomass and polyester into organosilane compounds, valuable chemicals ...
Polymers
Mar 20, 2023
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100
Researchers from the Universidad de Santiago de Chile and the University of Notre Dame, working with machine learning, have devised a method to identify organic compounds based on the refractive index at a single optical ...
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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