Bond length

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Bond length

In molecular geometry

Molecular geometry

Molecular geometry or molecular structure is the three-dimensional arrangement of the atoms that constitute a molecule. It determines several properties of a substance including its Reactivity , Chemical polarity, Phase , color, magnetism, and biological activity....
, bond length or bond distance is the average distance between nuclei of two bonded

Chemical bond

A chemical bond is the physical process responsible for the attractive interactions between atoms and molecules, and that which confers stability to diatomic and polyatomic chemical compounds....
atom

Atom

|-! bgcolor=gray | Properties|-||}The atom is a basic unit of matter consisting of a dense, central atomic nucleus surrounded by a electron cloud of electric charge electrons....
s in a molecule

Molecule

In chemistry, a molecule is defined as a sufficiently stable, electric charge neutral group of at least two atoms in a definite arrangement held together by very strong chemical bonds....
.

length is inversely related to bond order

Bond order

Bond order is the number of bonds between a pair of atoms. For example in nitrogen N=N the bond order is 3, 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....
, when more electron

Electron

The electron is a subatomic particle that carries a negative electric charge. It has elementary particle and is believed to be a point particle....
s participate in bond formation the bond will get shorter. Bond length is also inversely related to bond strength

Bond strength

In chemistry, bond strength is measured between two atoms joined in a chemical bond . It is the degree to which each atom linked to a central atom contributes to the valency of this central atom....
and the bond dissociation energy

Bond dissociation energy

In chemistry, bond dissociation energy, D0 or BDE, is one measure of the bond strength in a chemical bond. It is defined as the enthalpy when a bond is cleaved by homolysis, with reactants and products of the homolysis reaction at 0 K ....
, as a stronger bond is also a shorter bond. In a bond between two identical atoms half the bond distance is equal to the covalent radius

Covalent radius

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Encyclopedia

In molecular geometry

Molecular geometry

Chemical bond

Atom

|-! bgcolor=gray | Properties|-||}The atom is a basic unit of matter consisting of a dense, central atomic nucleus surrounded by a electron cloud of electric charge electrons....
s in a molecule

Molecule

In chemistry, a molecule is defined as a sufficiently stable, electric charge neutral group of at least two atoms in a definite arrangement held together by very strong chemical bonds....
.

Explanation

Bond length is inversely related to bond order

Bond order

Electron

Bond strength

Bond dissociation energy

Covalent radius

The covalent radius, rcov, is a measure of the size of atom that forms part of a covalent bond. It is measured either in picometres or ?ngstr?ms , with 1 ? = 100 pm....
. Bond lengths are measured in molecules by means of x-ray diffraction. A set of two atoms sharing a bond is unique going from one molecule to the next. For example the carbon to hydrogen bond in methane

Methane

Methane is a chemical compound with the molecular formula . It is the simplest alkane, and the principal component of natural gas. Methane's bond angles are 109.5 degrees....
is different from that in methyl chloride. It is however possible to make generalizations when the general structure is the same. the bond length is lose

Bond lengths of carbon with other elements

A table with experimental single bonds for carbon to other elements is given below. Bond lengths are given in picometers. By approximation the bond distance between two different atoms is the sum of the individuales covalent radii

Covalent radius

The covalent radius, rcov, is a measure of the size of atom that forms part of a covalent bond. It is measured either in picometres or ?ngstr?ms , with 1 ? = 100 pm....
(these are given in the chemical element

Chemical element

A chemical element is a type of atom that is distinguished by its atomic number; that is, by the number of protons in its atomic nucleus. The term is also used to refer to a pure chemical Chemical substance composed of atoms with the same number of protons....
articles for each element). As a general trend, bond distances decrease across the row in the periodic table

Periodic table

The periodic table of the chemical elements is a table method of displaying the chemical elements. Although precursors to this table exist, its invention is generally credited to Russian chemist Dmitri Mendeleev in 1869....
and increase down a group. This trend is identical to that of the atomic radius

Atomic radius

Atomic radius, is called the width of an atom, but it is true it is not a precisely defined physical quantity, nor is it constant in all circumstances....
.

H Hydrogen Hydrogen is the chemical element with atomic number 1. It is represented by the chemical symbol H. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly combustion and explosive Diatomic molecule gas with the molecular formula H2....	106 - 112	group 1 Group 1 * Group 1 element - an chemical element classification for Alkali metal* Group 1 - a FIA classification for auto racing that preceded Group N* Group One thoroughbred horse races, are the leading events in the sport....
Be Beryllium Beryllium is a chemical element with the symbol Be and atomic number 4.A Bivalent element, beryllium is found naturally only combined with other elements in minerals....	193	group 2 Alkaline earth metal The alkaline earth metals are a chemical series of chemical element comprising Periodic table group of the periodic table: beryllium , magnesium , calcium , strontium , barium and radium ....
Mg Magnesium Magnesium is a chemical element with the symbol Mg, atomic number 12, atomic weight 24.3050 and common oxidation number +2.Magnesium, an alkaline earth metal, is the ninth most abundance of the chemical elements in the universe by mass....	207	group 2 Alkaline earth metal The alkaline earth metals are a chemical series of chemical element comprising Periodic table group of the periodic table: beryllium , magnesium , calcium , strontium , barium and radium ....
B Boron Boron is a chemical element with atomic number 5 and the chemical symbol B. Boron is a trivalent metalloid element which occurs abundantly in the evaporite ores borax and ulexite....	156	group 13 Boron group The boron group is the chemical series of Chemical element in periodic table group in the periodic table. The boron group consists of boron , aluminium , gallium , indium , thallium , and ununtrium ....
Al	224	group 13 Boron group The boron group is the chemical series of Chemical element in periodic table group in the periodic table. The boron group consists of boron , aluminium , gallium , indium , thallium , and ununtrium ....
In Indium Indium is a chemical element with chemical symbol In and atomic number 49. This rare, soft, malleable and easily Fusible alloy Post-transition metal is chemically similar to aluminium or gallium but more closely resembles zinc ....	216	group 13 Boron group The boron group is the chemical series of Chemical element in periodic table group in the periodic table. The boron group consists of boron , aluminium , gallium , indium , thallium , and ununtrium ....
C Carbon Carbon is a chemical element with chemical symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalence?making four electrons available to form covalent bond chemical bonds....	120 - 154	group 14 Carbon group The carbon group is group 14 in the periodic table. Once also known as the tetrels , stemming from the earlier naming convention of this group as Group IVA....
Si Silicon Silicon is the most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. The atomic mass is 28.0855....	186	group 14 Carbon group The carbon group is group 14 in the periodic table. Once also known as the tetrels , stemming from the earlier naming convention of this group as Group IVA....
Sn Tin Tin is a chemical element with the symbol Sn and atomic number 50. Tin is obtained chiefly from the mineral cassiterite, where it occurs as an oxide, SnO2....	214	group 14 Carbon group The carbon group is group 14 in the periodic table. Once also known as the tetrels , stemming from the earlier naming convention of this group as Group IVA....
Pb Lead Lead is a main-group Chemical element with symbol Pb and atomic number 82. Lead is a soft, malleable poor metal, also considered to be one of the heavy metal ....	229	group 14 Carbon group The carbon group is group 14 in the periodic table. Once also known as the tetrels , stemming from the earlier naming convention of this group as Group IVA....
N Nitrogen Nitrogen is a chemical element that has the symbol N and atomic number 7 and atomic mass 14.00674?. Elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78% by volume of Earth's atmosphere....	147 - 210	group 15 Nitrogen group The Nitrogen group is periodic table group 15 of the periodic table and is also collectively named the pnictogens. This consists of nitrogen , phosphorus , arsenic , antimony , bismuth and ununpentium ....
P Phosphorus Phosphorus is the chemical element that has the symbol P and atomic number 15. The name comes from the and . A Valency nonmetal of the nitrogen group, phosphorus is commonly found in inorganic phosphate minerals....	187	group 15 Nitrogen group The Nitrogen group is periodic table group 15 of the periodic table and is also collectively named the pnictogens. This consists of nitrogen , phosphorus , arsenic , antimony , bismuth and ununpentium ....
As Arsenic Arsenic is a well-known chemical element that has the symbol As and atomic number 33. Arsenic was first documented by Albertus Magnus in 1250....	198	group 15 Nitrogen group The Nitrogen group is periodic table group 15 of the periodic table and is also collectively named the pnictogens. This consists of nitrogen , phosphorus , arsenic , antimony , bismuth and ununpentium ....
Sb Antimony Antimony is a chemical element with the symbol Sb and atomic number 51. A metalloid, antimony has four allotropy forms. The stable form of antimony is a blue-white metalloid....	220	group 15 Nitrogen group The Nitrogen group is periodic table group 15 of the periodic table and is also collectively named the pnictogens. This consists of nitrogen , phosphorus , arsenic , antimony , bismuth and ununpentium ....
Bi Bismuth Bismuth is a chemical element that has the symbol Bi and atomic number 83. This heavy, brittle, white crystalline trivalent poor metal has a pink tinge and chemically resembles arsenic and antimony....	230	group 15 Nitrogen group The Nitrogen group is periodic table group 15 of the periodic table and is also collectively named the pnictogens. This consists of nitrogen , phosphorus , arsenic , antimony , bismuth and ununpentium ....
O Oxygen Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]...	143 - 215	group 16 Chalcogen The chalcogens are the Chemical element in periodic table group 16 of the periodic table. It is sometimes known as the oxygen family. It consists of the chemical element oxygen , sulfur , selenium , tellurium , the radioactive element polonium , and the synthetic element ununhexium ....
S Sulfur Sulfur or sulphur is the chemical element that has the atomic number 16. It is denoted with the symbol S. It is an abundant Valence non-metal....	181 - 255	group 16 Chalcogen The chalcogens are the Chemical element in periodic table group 16 of the periodic table. It is sometimes known as the oxygen family. It consists of the chemical element oxygen , sulfur , selenium , tellurium , the radioactive element polonium , and the synthetic element ununhexium ....
Cr Chromium Chromium is a chemical element which has the symbol Cr and atomic number 24. It is a steely-gray, Lustre , hard metal that takes a high polish and has a high melting point....	192	group 6
Se Selenium Selenium is a chemical element with the atomic number 34, represented by the chemical symbol Se, an atomic mass of 78.96. It is a nonmetal, chemically related to sulfur and tellurium, and rarely occurs in its elemental state in nature....	198 - 271	group 16 Chalcogen The chalcogens are the Chemical element in periodic table group 16 of the periodic table. It is sometimes known as the oxygen family. It consists of the chemical element oxygen , sulfur , selenium , tellurium , the radioactive element polonium , and the synthetic element ununhexium ....
Te Tellurium Tellurium is a chemical element that has the symbol Te and atomic number 52. A brittle silver-white metalloid which looks like tin, tellurium is chemically related to selenium and sulfur....	205	group 16 Chalcogen The chalcogens are the Chemical element in periodic table group 16 of the periodic table. It is sometimes known as the oxygen family. It consists of the chemical element oxygen , sulfur , selenium , tellurium , the radioactive element polonium , and the synthetic element ununhexium ....
Mo Molybdenum Molybdenum , is a Group 6 element chemical element with the symbol Mo and atomic number 42. It has the List of elements by melting point melting point of any element....	208	group 6
W Tungsten Tungsten , also known as wolfram , is a chemical element that has the symbol W and atomic number 74.A steel-gray metal, tungsten is found in several ores, including wolframite and scheelite....	206	group 6
F Fluorine Fluorine is the chemical element with the symbol F and atomic number 9. Fluorine forms a single bond with itself in elemental form, resulting in the diatomic F2 molecule....	134	group 17 Halogen \|}The halogens or halogen elements are a chemical series of nonmetal chemical element from Periodic table group International Union of Pure and Applied Chemistry of the periodic table, comprising fluorine, F; chlorine, Cl; bromine, Br; iodine, I; and astatine, At....
Cl Chlorine Chlorine...	176	group 17 Halogen \|}The halogens or halogen elements are a chemical series of nonmetal chemical element from Periodic table group International Union of Pure and Applied Chemistry of the periodic table, comprising fluorine, F; chlorine, Cl; bromine, Br; iodine, I; and astatine, At....
Br Bromine Bromine , , meaning "stench " ), is a chemical element with the symbol Br and atomic number 35. A halogen element, bromine is a reddish-brown Volatility liquid at Standard conditions for temperature and pressure that is intermediate in reactivity between chlorine and iodine....	193	group 17 Halogen \|}The halogens or halogen elements are a chemical series of nonmetal chemical element from Periodic table group International Union of Pure and Applied Chemistry of the periodic table, comprising fluorine, F; chlorine, Cl; bromine, Br; iodine, I; and astatine, At....
I Iodine Iodine , is a chemical element that has the symbol I and atomic number 53. Naturally-occurring iodine is a single isotope with 74 neutrons....	213	group 17 Halogen \|}The halogens or halogen elements are a chemical series of nonmetal chemical element from Periodic table group International Union of Pure and Applied Chemistry of the periodic table, comprising fluorine, F; chlorine, Cl; bromine, Br; iodine, I; and astatine, At....
Table 1. Bond distance* of carbon to other elements in picometers*

Bond lengths in organic compounds

The actual bond length between two atoms in a molecule depends on such factors as the orbital hybridization and the electronic and steric nature of the substituent

Substituent

In organic chemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon. The suffix -yl is used when naming organic compounds that contain a substituent....
s. The carbon carbon bond length in diamond is 154 pm which is also the largest bond length that exists for ordinary carbon covalent bonds.

Unusually long bond lengths do exist. In one, tricyclobutabenzene

Tricyclobutabenzene

Tricyclobutabenzene is an aromatic hydrocarbon consisting of a benzene core with three cyclobutane rings fused onto it. This compound and related compounds are studied in the laboratory because they are often display unusual chemical conformations and because of their unusual reactivity....
, a bond length of 160 pm is reported. The current record holder is another cyclobutabenzene with length 174 pm based on X-ray crystallography

X-ray crystallography

X-ray crystallography is a method of determining the arrangement of atoms within a crystal, in which a beam of X-rays strikes a crystal and scatters into many different directions....
. In this type of compounds the cyclobutane ring would force 90° angles on the carbon atoms connected to the benzene ring where they ordinarily have angles of 120°.

The existence of a very long C-C bond length of up to 290 pm is claimed in a dimer of two tetracyanoethylene

Tetracyanoethylene

Tetracyanoethylene is a yellow colored organic compound consisting of ethylene with the four hydrogen atom replaced with cyano groups. It is an important member of the cyanocarbons....
dianions although this concerns a 2-electron-4-center bond . This type of bonding has also been observed in dimers of neutral phenalene

Phenalene

Phenalene is a polycyclic aromatic hydrocarbon . Like many PAHs, it is an atmospheric pollutant formed during the combustion of fossil fuels....
dimers. The bond lengths of these so-called pancake bonds are up to 305 pm.

Shorter than average carbon carbon bonds distances are also possible, alkene

Alkene

In organic chemistry, an alkene, olefin, or olefine is an Saturation chemical compound containing at least one carbon-to-carbon double bond....
s and alkyne

Alkyne

Alkynes are hydrocarbons that have at least one triple bond between two carbon atoms, with the formula CnH2n-2. The alkynes are traditionally known as acetylenes or the acetylene series, although the name acetylene is also used to refer specifically to the simplest member of the series, known as e...
s have bond lengths of respectively 133 and 120 pm due to increased s-character of the sigma bond

Sigma bond

In chemistry, sigma bonds are the strongest type of covalent bond chemical bond. Sigma bonding is most clearly defined for diatomic molecules using the language and tools of symmetry groups....
.In benzene

Benzene

Benzene, or benzol, is an organic compound chemical compound and a known carcinogen with the molecular formula Carbon6Hydrogen6....
all bonds have the same length: 139 pm. In carbon carbon single bonds increased s-character is also notable in the central bond of diacetylene

Diacetylene

Diacetylene , with the formula C4H2, is a highly alkyne hydrocarbon that contains one single bond and two triple bonds. It is the first in the series of polyynes....
(137 pm) and that of a certain tetrahedrane dimer

Tetrahedrane

Tetrahedrane is a platonic hydrocarbon with chemical formula 44 and a tetrahedron structure. Extreme angle strain prevents this molecule from forming outside of man-made production....
(144 pm).

In propionitrile

Propionitrile

Propionitrile, or ethyl cyanide, is a low-molecular weight nitrile with the molecular formula C2H5CN. It is a clear liquid with an ethereal, sweet odor....
the cyano group withdraws electrons also resulting in a reduced bond length (144 pm). Squeezing a CC bond is also possible by application of strain. An unusual organic compound exists called In-Methylcyclophane

In-Methylcyclophane

In-Methylcyclophanes are organic compounds and members of a larger family of cyclophanes. These compounds only exist in the laboratory and help to explain how chemical bonds in molecules adapt to strain energy....
with a very short bond distance of 147 pm for the methyl group being squeezed between a trypticene and a phenyl group. In an in silico

In silico

In silico is an expression used to mean "performed on computer or via computer simulation." The phrase is coined in analogy to the Latin language phrases in vivo and in vitro which are commonly used in biology and refer to experiments done in living organisms and outside of living organisms, respectively....
experiment a bond distance of 136 pm is estimated for neopentane

Neopentane

Neopentane, also called dimethylpropane or 2,2-dimethylpropane, is a double-branched-chain alkane with five carbon atoms. Neopentane is an extremely flammable gas at room temperature and pressure which can condense into a highly Volatility liquid on a cold day, in an ice bath, or when compressed to a higher pressure....
locked up in fullerene

Fullerene

Fullerene are a family of carbon Allotropy, molecules composed entirely of carbon, in the form of a hollow sphere, ellipsoid, cylinder , or plane....
. The smallest theoretical CC single bond obtained in this study is 132 pm for a hypothetical adamantane

Adamantane

Adamantane is a colourless, crystalline compound with a camphor-like odour. With a formula C10H16, it is a cycloalkane and also the simplest diamondoid....
like molecule.

In the same study it is estimated that for ethane

Ethane

Ethane is a chemical compound with chemical formula C2H6. It is the only two-carbon alkane, that is, an aliphatic hydrocarbon....
it takes 2.8 kJ

Joule

The joule is the SI derived unit of energy in the International System of Units. It is defined as:One joule is the amount of energy required to perform the following actions:...
/mol

Mole (unit)

The mole is a Units of measurement of amount of substance: it is an SI base unit, and one of the few units used to measure this physical quantity....
to stretch the CC bond by 5 pm from its equilibrium value and only 3.5 kJ/mol to squeeze it by the same amount. On the other hand, stretching and squeezing by 15 pm requires 21.9 and 37.7 kJ/mol.

Bond lengths in organic compounds
C-H	length (pm)	C-C	length (pm)	Multiple bonds	length (pm)
sp³-H	110	sp³-sp³	154	Benzene Benzene Benzene, or benzol, is an organic compound chemical compound and a known carcinogen with the molecular formula Carbon6Hydrogen6....	140
sp²-H	109	sp³-sp²	150	Alkene Alkene In organic chemistry, an alkene, olefin, or olefine is an Saturation chemical compound containing at least one carbon-to-carbon double bond....	134
sp-H	108	sp²-sp²	135	Alkyne Alkyne Alkynes are hydrocarbons that have at least one triple bond between two carbon atoms, with the formula CnH2n-2. The alkynes are traditionally known as acetylenes or the acetylene series, although the name acetylene is also used to refer specifically to the simplest member of the series, known as e...	120
		sp³-sp	146	Allene Allene An allene is a hydrocarbon in which one atom of carbon is connected by covalent bond with two other atoms of carbon. Allene also is the common name for the parent compound of this series, propadiene....	130
		sp²-sp	143
		sp-sp	120

External links

Utah Chemists Find Longest Carbon-Carbon Bond