Triple bond
Encyclopedia
A triple bond in chemistry
is a chemical bond
between two chemical elements involving six bonding electrons instead of the usual two in a covalent single bond
. The most common triple bond, that between two carbon atoms, can be found in alkynes. Other functional group
s containing a triple bond are cyanide
s and isocyanide
s. Some diatomic molecules, such as dinitrogen and carbon monoxide
are also triple bonded. In skeletal formula
the triple bond is drawn as three parallel lines (≡) between the two connected atoms; in typography, this is accomplished with the identity operator.
Triple bonds are stronger than single bonds
or double bond
s and they are also shorter. The bond order
is three.
). The p-orbitals are perpendicular
on the y-axis and the z-axis. When the carbon atoms approach each other the sp orbitals overlap to form a sp-sp sigma bond
. At the same time the pz-orbitals approach and together they form a pz-pz pi-bond. Likewise, the other pair of py-orbitals form a py-py pi-bond. The result is formation of one sigma bond and two pi bonds.
In bent bond theory the triple bond can also formed by the overlapping of three sp3 lobes without the need to invoke a pi-bond.
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
is a chemical bond
Chemical bond
A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electromagnetic force attraction between opposite charges, either between electrons and nuclei, or as the result of a dipole attraction...
between two chemical elements involving six bonding electrons instead of the usual two in a covalent single bond
Covalent bond
A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....
. The most common triple bond, that between two carbon atoms, can be found in alkynes. Other functional group
Functional group
In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...
s containing a triple bond are cyanide
Cyanide
A cyanide is a chemical compound that contains the cyano group, -C≡N, which consists of a carbon atom triple-bonded to a nitrogen atom. Cyanides most commonly refer to salts of the anion CN−. Most cyanides are highly toxic....
s and isocyanide
Isocyanide
An isocyanide is an organic compound with the functional group -N≡C. It is the isomer of the related cyanide , hence the prefix iso....
s. Some diatomic molecules, such as dinitrogen and carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
are also triple bonded. In skeletal formula
Skeletal formula
The skeletal formula of an organic compound is a shorthand representation of its molecular structure, developed by the organic chemist, Friedrich August Kekulé von Stradonitz. Skeletal formulae are ubiquitous in organic chemistry, because they are relatively quick and simple to draw. Carbon and...
the triple bond is drawn as three parallel lines (≡) between the two connected atoms; in typography, this is accomplished with the identity operator.
Triple bonds are stronger than single bonds
Covalent bond
A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....
or double bond
Double bond
A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two. The most common double bond, that between two carbon atoms, can be found in alkenes. Many types of double bonds between two different elements exist, for example in...
s and they are also shorter. The bond order
Bond order
Bond order is the number of chemical bonds between a pair of atoms. For example, in diatomic nitrogen N≡N the bond order is 3, while in acetylene H−C≡C−H the bond order between the two carbon atoms is also 3, and the C−H bond order is 1. Bond order gives an indication to the stability of a bond....
is three.
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| acetylene Acetylene Acetylene is the chemical compound with the formula C2H2. It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in pure form and thus is usually handled as a solution.As an alkyne, acetylene is unsaturated because... , H−C≡C−H |
cyanogen Cyanogen Cyanogen is the chemical compound with the formula 2. It is a colorless, toxic gas with a pungent odor.The molecule is a pseudohalogen. Cyanogen molecules consist of two CN groups — analogous to diatomic halogen molecules, such as Cl2, but far less oxidizing... , N≡C−C≡N |
carbon monoxide Carbon monoxide Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal... , C≡O |
| Chemical compounds with triple bonds |
Bonding
The type of bonding can be explained in terms of orbital hybridization. In the case of acetylene each carbon atom has two sp orbitals and two p-orbitals. The two sp orbitals are linear with 180° angles and occupy the x-axis (cartesian coordinate systemCartesian coordinate system
A Cartesian coordinate system specifies each point uniquely in a plane by a pair of numerical coordinates, which are the signed distances from the point to two fixed perpendicular directed lines, measured in the same unit of length...
). The p-orbitals are perpendicular
Perpendicular
In geometry, two lines or planes are considered perpendicular to each other if they form congruent adjacent angles . The term may be used as a noun or adjective...
on the y-axis and the z-axis. When the carbon atoms approach each other the sp orbitals overlap to form a sp-sp sigma bond
Sigma bond
In chemistry, sigma bonds are the strongest type of covalent chemical bond. They are formed by head-on overlapping between atomic orbitals. Sigma bonding is most clearly defined for diatomic molecules using the language and tools of symmetry groups. In this formal approach, a σ-bond is...
. At the same time the pz-orbitals approach and together they form a pz-pz pi-bond. Likewise, the other pair of py-orbitals form a py-py pi-bond. The result is formation of one sigma bond and two pi bonds.
In bent bond theory the triple bond can also formed by the overlapping of three sp3 lobes without the need to invoke a pi-bond.