Covalent bond

covalentcovalentlycovalently bondedcovalent bondscovalent bondingcovalently boundbondsbondbondedcovalent compound
A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.wikipedia
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Chemical bond

bondbondschemical bonds
A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.
The bond may result from the electrostatic force of attraction between oppositely charged ions as in ionic bonds or through the sharing of electrons as in covalent bonds.

Sigma bond

σ bondsigmasigma bonds
Covalent bonding includes many kinds of interactions, including σ-bonding, π-bonding, metal-to-metal bonding, agostic interactions, bent bonds, and three-center two-electron bonds.
In chemistry, sigma bonds (σ bonds) are the strongest type of covalent chemical bond.

Pi bond

pi electronπ bondπ bonds
Covalent bonding includes many kinds of interactions, including σ-bonding, π-bonding, metal-to-metal bonding, agostic interactions, bent bonds, and three-center two-electron bonds. In organic chemistry, when a molecule with a planar ring obeys Hückel's rule, where the number of π electrons fit the formula 4n + 2 (where n is an integer), it attains extra stability and symmetry.
In chemistry, pi bonds (π bonds) are covalent chemical bonds where two lobes of an orbital on one atom overlap two lobes of an orbital on another atom and this overlap occurs laterally.

Bent bond

banana bondbanana bondsbent bond model
Covalent bonding includes many kinds of interactions, including σ-bonding, π-bonding, metal-to-metal bonding, agostic interactions, bent bonds, and three-center two-electron bonds.
In organic chemistry, a bent bond, also known as a banana bond, is a type of covalent chemical bond with a geometry somewhat reminiscent of a banana.

Gilbert N. Lewis

Gilbert Newton LewisG. N. LewisLewis
The idea of covalent bonding can be traced several years before 1919 to Gilbert N. Lewis, who in 1916 described the sharing of electron pairs between atoms.
Lewis was best known for his discovery of the covalent bond and his concept of electron pairs; his Lewis dot structures and other contributions to valence bond theory have shaped modern theories of chemical bonding.

Electron

electronse − electron mass
These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding.
Chemical bonds between atoms were explained by Gilbert Newton Lewis, who in 1916 proposed that a covalent bond between two atoms is maintained by a pair of electrons shared between them.

Double bond

double bondsdoubledouble-bond
Multiple pairs represent multiple bonds, such as double bonds and triple bonds.
A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two.

Delocalized electron

delocalizationdelocalizeddelocalize
Covalent bonding that entails sharing of electrons over more than two atoms is said to be delocalized.
In chemistry, delocalized electrons are electrons in a molecule, ion or solid metal that are not associated with a single atom or a covalent bond.

Hydrogen

HH 2 hydrogen gas
In the molecule, the hydrogen atoms share the two electrons via covalent bonding. Walter Heitler and Fritz London are credited with the first successful quantum mechanical explanation of a chemical bond (molecular hydrogen) in 1927.
Since hydrogen readily forms covalent compounds with most nonmetallic elements, most of the hydrogen on Earth exists in molecular forms such as water or organic compounds.

Molecule

molecularmoleculesmolecular structure
For many molecules, the sharing of electrons allows each atom to attain the equivalent of a full outer shell, corresponding to a stable electronic configuration.
Molecules are held together by either covalent bonding or ionic bonding.

Triple bond

tripletriple-bondtriple bonds
Multiple pairs represent multiple bonds, such as double bonds and triple bonds.
A triple bond in chemistry is a chemical bond between two atoms involving six bonding electrons instead of the usual two in a covalent single bond.

Valence (chemistry)

divalentvalencevalency
The prefix co- means jointly, associated in action, partnered to a lesser degree, etc.; thus a "co-valent bond", in essence, means that the atoms share "valence", such as is discussed in valence bond theory.
According to Lewis, covalent bonding leads to octets by the sharing of electrons, and ionic bonding leads to octets by the transfer of electrons from one atom to the other.

Atom

atomsatomic structureatomic
A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.
By this mechanism, atoms are able to bond into molecules and other types of chemical compounds like ionic and covalent network crystals.

Electronegativity

electronegativeelectropositiveelectronegativities
Covalency is greatest between atoms of similar electronegativities.
Pauling first proposed the concept of electronegativity in 1932 as an explanation of the fact that the covalent bond between two different atoms (A–B) is stronger than would be expected by taking the average of the strengths of the A–A and B–B bonds.

Octet rule

octetduet ruleoctet (8-electron) rule
In the diagram of methane shown here, the carbon atom has a valence of four and is, therefore, surrounded by eight electrons (the octet rule), four from the carbon itself and four from the hydrogens bonded to it.
The electrons shared by the two atoms in a covalent bond are counted twice, once for each atom.

Valence bond theory

valence bondvalencevalence bonds
The prefix co- means jointly, associated in action, partnered to a lesser degree, etc.; thus a "co-valent bond", in essence, means that the atoms share "valence", such as is discussed in valence bond theory.
Specifically, Walter Heitler determined how to use Schrödinger's wave equation (1926) to show how two hydrogen atom wavefunctions join together, with plus, minus, and exchange terms, to form a covalent bond.

Carbon dioxide

CO 2 CO2carbon dioxide (CO 2 )
Such covalent substances are usually gases, for example, HCl, SO 2, CO 2, and CH 4.
Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms.

Single bond

singleC–H and C–C bondsingle bonds
A single bond is usually a σ bond.
Therefore, a single bond is a type of covalent bond.

Network covalent bonding

network solidnetwork solidscovalent network
Network covalent structures (or giant covalent structures) contain large numbers of atoms linked in sheets (such as graphite), or 3-dimensional structures (such as diamond and quartz).
A network solid or covalent network solid is a chemical compound (or element) in which the atoms are bonded by covalent bonds in a continuous network extending throughout the material.

Fritz London

FritzLondonLondon, Fritz Wolfgang
Walter Heitler and Fritz London are credited with the first successful quantum mechanical explanation of a chemical bond (molecular hydrogen) in 1927.
It is no coincidence that the Heitler–London work appeared shortly after the introduction of quantum mechanics by Heisenberg and Schrödinger, because quantum mechanics was crucial in their explanation of the covalent bond.

Macromolecule

macromoleculesmacromolecularmacromolecular chemistry
There are several types of structures for covalent substances, including individual molecules, molecular structures, macromolecular structures and giant covalent structures.
For example, while biology refers to macromolecules as the four large molecules comprising living things, in chemistry, the term may refer to aggregates of two or more molecules held together by intermolecular forces rather than covalent bonds but which do not readily dissociate.

Chemical polarity

polarpolaritynonpolar
Covalent bonds are also affected by the electronegativity of the connected atoms which determines the chemical polarity of the bond.
The terms "polar" and "nonpolar" are usually applied to covalent bonds, that is, bonds where the polarity is not complete.

Polyethylene

polythenePEpolyethene
Macromolecular structures have large numbers of atoms linked by covalent bonds in chains, including synthetic polymers such as polyethylene and nylon, and biopolymers such as proteins and starch.
The individual macromolecules are not covalently linked.

Graphite

graphiticblack leadplumbago
Network covalent structures (or giant covalent structures) contain large numbers of atoms linked in sheets (such as graphite), or 3-dimensional structures (such as diamond and quartz).
Atoms in the plane are bonded covalently, with only three of the four potential bonding sites satisfied.

Organic chemistry

organicorganic chemistorganic chemical
In organic chemistry, when a molecule with a planar ring obeys Hückel's rule, where the number of π electrons fit the formula 4n + 2 (where n is an integer), it attains extra stability and symmetry.
Organic chemistry is a subdiscipline of chemistry that studies the structure, properties and reactions of organic compounds, which contain carbon in covalent bonding.