covalent bond

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Related to Unsaturated bond: Polar bond

bond

 [bond]
the linkage between atoms or radicals of a chemical compound, or the symbol representing this linkage and indicating the number and attachment of the valencies of an atom in constitutional formulas, represented by a pair of dots or a line between atoms, e.g., H—O—H, H—C≡C—H or H:O:H, H:C:::C:H.
coordinate covalent bond a covalent bond in which one of the bonded atoms furnishes both of the shared electrons.
covalent bond a chemical bond between two atoms or radicals formed by the sharing of a pair (single bond), two pairs (double bond), or three pairs of electrons (triple bond).
disulfide bond a strong covalent bond, —S—S—, important in linking polypeptide chains in proteins, the linkage arising as a result of the oxidation of the sulfhydryl (SH) groups of two molecules of cysteine.
high-energy phosphate bond an energy-rich phosphate linkage present in adenosine triphosphate (ATP), phosphocreatine, and certain other biological molecules. On hydrolysis at pH 7 it yields about 8000 calories per mole, in contrast to the 3000 calories yielded by phosphate esters. The bond stores energy that is used to drive biochemical processes, such as the synthesis of macromolecules, contraction of muscles, and the production of the electrical potentials for nerve conduction.
high-energy sulfur bond an energy-rich sulfur linkage, the most important of which occurs in the acetyl-CoA molecule, the main source of energy in fatty acid biosynthesis.
hydrogen bond a weak, primarily electrostatic, bond between a hydrogen atom bound to a highly electronegative element (such as oxygen or nitrogen) in a given molecule, or part of a molecule, and a second highly electronegative atom in another molecule or in a different part of the same molecule.
ionic bond a chemical bond in which electrons are transferred from one atom to another so that one bears a positive and the other a negative charge, the attraction between these opposite charges forming the bond.
peptide bond the —CO—NH— linkage formed between the carboxyl group of one amino acid and the amino group of another; it is an amide linkage joining amino acids to form peptides.
References in periodicals archive ?
A step toward comprehension of heavy unsaturated bonds. Chem.
FTIR spectroscopy (EQUINOX55, Bruker, Germen) was employed to determine relative conversion percentage (CP) of unsaturated bond during UV curing progress.
Cu adding decreases the crystallinity, branched degree and unsaturated degree of PE coatings, but increases the branched degree and unsaturated bonds of PEPTFE coatings and decreases the structural ordering because of the crosslinking process of polymer chains.
Formation of a certain [sp.sup.2] bond percentage in diamond composites is attributed to this characteristic and the use of hydrogen during Diamond like Carbon (DLC) synthesis has proven to reduce the amount of unsaturated bonds that leads to [sp.sup.2] bond formation [19].
However, such polyol esters retain unsaturated bonds in their fatty acid chain portions, which represent sites where the compounds may still react with atmospheric oxygen.