Chemical binding, electron pairs

Covalent. That type of chemical binding in which the electron systems of the participating atoms merge without complete transfer of charge from one atom to another employing one or more shared pair bonds opposite of electrovalent. 

The shared-electron pair model introduced by G.N. Lewis showed how chemical bonds could form in the absence of electrostatic attraction between oppositely-charged ions. As such, it has become the most popular and generally useful model of bonding in all substances other than metals. A chemical bond forms when electrons are simultaneously attracted to two nuclei, thus acting to bind them together in an energetically -stable arrangement. The covalent bond is formed when two atoms are able to share a... 

The size-and-shape factor is of special importance with respect to electron confinement in atoms, molecules, crystals and interfaces. This confinement, empirically characterised by parameters such as electronegativity is the decisive fundamental factor that decides chemical reactivity. The demonstration that atomic electronegativity is equivalent to the chemical quantum potential of the valence state [108] holds the key to molecule formation by electron pairing and space-like delocalization. It opens a new angle on the nature of chemical binding, molecular structure, chemical equilibrium and surfaces. 

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