covalent bond


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Related to covalent bond: nonpolar covalent bond, Noncovalent bond

covalent bond

(kō'vā`lənt): see chemical bondchemical bond,
mechanism whereby atoms combine to form molecules. There is a chemical bond between two atoms or groups of atoms when the forces acting between them are strong enough to lead to the formation of an aggregate with sufficient stability to be regarded as an
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.

Covalent Bond

 

a chemical bond between two atoms that is formed by a shared electron pair (one electron from each atom). Covalent bonds exist both in molecules (in all states of aggregation) and between the atoms that form crystal lattices. They may unite like atoms (in H2 and C12 molecules and diamond crystals) or unlike atoms (in water molecules and crystals of carborundum, SiC).

Almost all the main bonds in the molecules of organic compounds are covalent (C—C, C—H, C—N, and so on). Covalent bonds are very strong, which explains the low chemical activity of paraffin hydrocarbons. Many inorganic compounds whose crystals have an atomic lattice (that is, are formed by a covalent bond) are refractory and characterized by great hardness and wear resistance; among them are certain carbides, suicides, borides, and nitrides (particularly borazone, BN), which are widely used in modern technology.

V. A. KIREEV

covalent bond

[kō′vā·lənt ′bänd]
(chemistry)
A bond in which each atom of a bound pair contributes one electron to form a pair of electrons. Also known as electron pair bond.
References in periodicals archive ?
Upon adsorption, the weakly bonded halogen substituents are split off with the aid of the catalytic properties of the metal surface, and the subsequently formed dangling bonds are coupled to be C-C bond through the mobility of the alkyl on the surface of metal in mechanism 1 as a direct way of establishing covalent bonds after the dissociation of C-X (halogen atom) bond, and the dangling bonds are used to form organometallic intermediates subsequently ending in C-C coupling by annealing to proper temperature as expressed in mechanism 2.
As it was mentioned in Section 3, the covalent bonds between two carbon atoms are modeled using the beam element and each atom is considered as point mass element.
The degree of electron aggregation enlarges after Ga defect (Figure 3(b)), the overlap population increases, the covalent bond of Ga-N is stronger and the bond length of Ga-N is shorter than that of intact surface.
Since van der Waals interactions are non-bonded, in comparison with covalent bonds between atoms, van der Waals interactions are very weak.
Here we consider ionic bonds, covalent bonds and the concept of the rule-of-two that is central to chemistry.
Thus the millions of compounds necessary for life will have a skeleton of carbon atoms, each with four, not two, not three, not five, nor six, covalent bonds. Carbon thus acts as a compelling attractor.
An increase of the viscosity is reported by the addition of a maleated compatibilizing agent due to strong interactions provoked by maleic groups and/or by the formation of covalent bonds [21-23].
Our calculations show that using NTCOCl provides the possibility of creating covalent bond between 2ME drug and nanotube, while NTCOOH is not suitable for this task due to high energy barrier.
In all complexes were observed the formation of covalent bond between glyphosate and the [B.sub.12][N.sub.12].
Key statement: A functionalized elastomer defined by the formula where [pi] includes a polymer chain, [theta] includes a group 14 element, [R.sup.1] and [R.sup.2] each independently include hydrogen, or a monovalent organic group, or a polymer chain, [R.sup.3] and [R.sup.4] each independently include a divalent organic group or a covalent bond, [R.sup.5], [R.sup.6], [R.sup.7], [R.sup.8] and [R.sup.9] each independently include a monovalent organic group or a hydrogen atom.
Because aldehyde groups are efficiently introduced into the TEMPO-oxidized pulps, the wet tensile strength improvement of the handsheets must be brought about by inter-fiber covalent bond formation.
The third component features a macromolecule as a matrix component the fourth component includes low molecular-weight parts that bond the thin film particles by a covalent bond.