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In nylon, hydrogen bonds between carbonyl and the amide NH effectively link adjacent chains, which gives the material mechanical strength. Hydrogen bonds also affect the aramid fibre, where hydrogen bonds stabilize the linear chains laterally. The chain axes are aligned along the fibre axis, making the fibres extremely stiff and strong.
By some definitions, "organic" compounds are only required to contain carbon. However, most of them also contain hydrogen, and because it is the carbon-hydrogen bond that gives this class of compounds most of its particular chemical characteristics, carbon-hydrogen bonds are required in some definitions of the word "organic" in chemistry. [12]
The final bonding motif is the non-classical dihydride also known as sigma bond dihydrogen adducts or simply dihydrogen complexes. The [W(PR 3 ) 2 (CO) 3 (H 2 )] complex was the first well characterized example of both a non-classical dihydride and sigma-bond complex in general.
Hydrogen bonds of the form A--H•••B occur when A and B are two highly electronegative atoms (usually N, O or F) such that A forms a highly polar covalent bond with H so that H has a partial positive charge, and B has a lone pair of electrons which is attracted to this partial positive charge and forms a hydrogen bond. [23]: 702 Hydrogen ...
While the diagram depicted in Figure 2 shows the right-hand atom as the donor, an equivalent diagram can be constructed using the left-hand atom as the donor. This bonding scheme is succinctly summarized by the following two resonance structures: I—I···I − ↔ I − ···I—I (where "—" represents a single bond and ...
In the A-U Hoogsteen base pair, the adenine is rotated 180° about the glycosidic bond, resulting in an alternative hydrogen bonding scheme which has one hydrogen bond in common with the Watson-Crick base pair (adenine N6 and thymine N4), while the other hydrogen bond, instead of occurring between adenine N1 and thymine N3 as in the Watson ...
Hydrogen bonds contribute to the stability of ion pairs with e.g. protonated ammonium ions, and with anions is formed by deprotonation as in the case of carboxylate, phosphate etc; then the association constants depend on the pH. Entropic driving forces for ion pairing (in absence of significant H-bonding contributions) are also found in ...
The most common arrangement of hydrogen atoms around an oxygen is tetrahedral with two hydrogen atoms covalently bonded to oxygen and two attached by hydrogen bonds. Since the hydrogen bonds vary in length many of these water molecules are not symmetrical and form transient irregular tetrahedra between their four associated hydrogen atoms. [4]