covalence
covalency BrE

An advantage of the sulfur chemical element is its high covalence.

Its covalence character is higher, which is responsible for its solubility in organic solvent.

June 1 - The term covalence in relation to chemical bonding models is first used by Irving Langmuir.

Langmuir wrote that "we shall denote by the term covalence the number of pairs of electrons that a given atom shares with its neighbors."

The concept of covalence was developed in the middle of the nineteenth century in an attempt to rationalize the formulae of different chemical compounds.

The tape products line was then divested as part of Covalence Specialty Materials which later merged with Berry Plastics.

NEWBURGH "Covalence," sculpture and paintings by Emil Alzamora and Stephen Spaccarelli.

"Covalence: Emil Alzamora and Stephen Spaccarelli," Yellow Bird Gallery, 19 Front Street, Newburgh, through March 19; (845) 561-7204 or at www.yellowbirdgallery.com.

The term "covalence" in regard to bonding was first used in 1919 by Irving Langmuir in a Journal of the American Chemical Society article entitled "The Arrangement of Electrons in Atoms and Molecules".

In 1919, Irving Langmuir, borrowed the term to explain Gilbert N. Lewis's cubical atom model by stating that "the number of pairs of electrons which any given atom shares with the adjacent atoms is called the covalence of that atom."

Therefore covalency effects must also be taken into account.

The "covalency" whatever that means is a continuum.

Ligand field theory a development of crystal field theory taking covalency into account.

Covalency is greatest between atoms of similar electronegativity.

They are highly incompressible solids with high electron density and high bond covalency.

Even the most electronegative/electropositive pairs such as caesium fluoride exhibit a degree of covalency.

With smaller cations, the structural types suggest greater polarization of the polonide ion, or greater covalency in the bonding.

The higher the contribution of the charge transfer state to the ground state, the higher is the ground state covalency indicating stronger metal-ligand bonding.

Zinc tends to form bonds with a greater degree of covalency and it forms much more stable complexes with N- and S- donors.

This polarization of the negative ion leads to a build-up of extra charge density between the two nuclei, i.e., to partial covalency.

More sophisticated models embrace covalency, and this approach is described by ligand field theory (LFT) and Molecular orbital theory (MO).

For example, Na-Cl and Mg-O bonds have a few percent covalency, while Si-O bonds are usually 50% ionic and 50% covalent.

Formal oxidation numbers require particular caution for molecules where the bonding is covalent, since the formal oxidation numbers require the heterolytic removal of ligands, which essentially denies covalency.

This rising-edge transition can be fit to a valence bond configuration (VBCI) model to obtain the composition of the ground state wavefunction and information on ground state covalency.

If the impurity ion is bigger than the regular ion, the displacement arises because of different covalency of the chemical bonds with the nearest neighbors for the impurity and regular ions.

The slight decrease in covalency for B-N bonds compared to C-C bonds reduces the hardness from 100 GPa for diamond down to 48 GPa in c-BN.

The partly ionic structure of BN layers in h-BN reduces covalency and electrical conductivity, whereas the interlayer interaction increases resulting in higher hardness of h-BN relative to graphite.

In terms of Lewis structures, formal charge is used in the description, comparison and assessment of likely topological and resonance structures by determining the apparent electronic charge of each atom within, based upon its electron dot structure assuming exclusive covalency or non-polar bonding.