Energy & Green Tech
Salts are cheap and sustainable materials that can be used to store energy (heat) over periods ranging from hours to years without loss. This works via so-called hydration-dehydration processes. Energy release (discharge) ...
Jun 10, 2020
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Energy & Green Tech
The search for renewable energy sources, which include wind, solar, hydroelectric dams, geothermal, and biomass, has preoccupied scientists and policymakers alike, due to their enormous potential in the fight against climate ...
Jun 9, 2020
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Engineering
Roads always seem to need repairs. Luna Lu is giving concrete the ability to "talk" and even heal itself.
May 20, 2020
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Energy & Green Tech
A research team led by Prof. Yi-Chun LU from the Faculty of Engineering at The Chinese University of Hong Kong (CUHK) has taken a critical step forward in improving high-energy batteries by introducing a novel electrolyte ...
May 14, 2020
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3237
Energy & Green Tech
Scientist Heinz Frei has spent decades working toward building an artificial version of one of nature's most elegant and effective machines: the leaf.
Mar 19, 2020
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284
Energy & Green Tech
York University researchers have discovered a way to make Lithium-powered batteries more environmentally friendly while retaining performance, stability and storage capacity.
Mar 5, 2020
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Electronics & Semiconductors
A team of Brown University researchers has made substantial progress in an effort to create a new type of molecular data storage system.
Feb 4, 2020
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923
Electronics & Semiconductors
Slightly bending semiconductors made of organic materials can roughly double the speed of electricity flowing through them and could benefit next-generation electronics such as sensors and solar cells, according to Rutgers-led ...
Dec 3, 2019
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169
Electronics & Semiconductors
Solution-processed semiconductors, including materials such as perovskites and quantum dots (i.e., small particles of matter in the quantum size regime), are substances with a conductivity ranging between that of insulators ...
Engineering
Organic electronic devices, which are made of small molecules or polymers (i.e., substances composed primarily or completely of similar units bound together) are known to have several advantageous properties. In fact, organic ...
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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