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Inductive effect
 
 
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The inductive effect in chemistry
Chemistry

Chemistry is the science concerned with the composition, structure, and properties of matter, as well as the changes it undergoes during chemical reactions....
 is an experimentally observable effect of the transmission of charge
Charge (physics)

In physics, a charge may refer to one of many different quantities, such as the electric charge in electromagnetism or the color charge in quantum chromodynamics....
 through a chain of atoms 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....
 by electrostatic induction
Electrostatic induction

Electrostatic induction is a redistribution of electrical charge in an object, caused by the influence of nearby charges. Induction was discovered by British scientist John Canton in 1753 and Swedish professor Johan Carl Wilcke in 1762....
. The net polar effect
Polar effect

The Polar effect or electronic effect in chemistry is the effect exerted by a substituent on modifying electrostatic forces operating on a nearby chemical reaction center....
 exerted by a 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....
 is a combination of this inductive effect and the mesomeric effect
Mesomeric effect

The mesomeric effect or resonance effect in chemistry is a property of substituents or functional groups in a chemical compound. The effect is used in a qualitative way and describes the electron withdrawing or releasing properties of substituents based on relevant resonance structures and is symbolized by the letter M....
.

The electron cloud
Electron cloud

Electron cloud is not a term used by the Nobel Prize laureate and acclaimed educator Richard Feynman in The Feynman Lectures on Physics for discussing "exactly what is an electron?"....
 in a s-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....
 between two unlike atoms is not uniform and is slightly displaced towards the more electronegative
Electronegativity

Electronegativity, symbol χ, is a chemical property that describes the ability of an atom to attract electrons towards itself in a covalent bond....
 of the two atoms. This causes a permanent state of bond polarization
Polar bond

Polar bond may refer to:Polar bond* Chemical polarity* Covalent bond* Bond dipole moment* Partial charge* Dipoles#Molecular dipoles* Electronegativity...
, where the more electronegative atom has a slight negative charge(d-) and the other atom has a slight positive charge(d+).

If the electronegative atom is then joined to a chain of atoms, usually carbon
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....
, the positive charge is relayed to the other atoms in the chain.






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Encyclopedia


The inductive effect in chemistry
Chemistry

Chemistry is the science concerned with the composition, structure, and properties of matter, as well as the changes it undergoes during chemical reactions....
 is an experimentally observable effect of the transmission of charge
Charge (physics)

In physics, a charge may refer to one of many different quantities, such as the electric charge in electromagnetism or the color charge in quantum chromodynamics....
 through a chain of atoms 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....
 by electrostatic induction
Electrostatic induction

Electrostatic induction is a redistribution of electrical charge in an object, caused by the influence of nearby charges. Induction was discovered by British scientist John Canton in 1753 and Swedish professor Johan Carl Wilcke in 1762....
. The net polar effect
Polar effect

The Polar effect or electronic effect in chemistry is the effect exerted by a substituent on modifying electrostatic forces operating on a nearby chemical reaction center....
 exerted by a 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....
 is a combination of this inductive effect and the mesomeric effect
Mesomeric effect

The mesomeric effect or resonance effect in chemistry is a property of substituents or functional groups in a chemical compound. The effect is used in a qualitative way and describes the electron withdrawing or releasing properties of substituents based on relevant resonance structures and is symbolized by the letter M....
.

The electron cloud
Electron cloud

Electron cloud is not a term used by the Nobel Prize laureate and acclaimed educator Richard Feynman in The Feynman Lectures on Physics for discussing "exactly what is an electron?"....
 in a s-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....
 between two unlike atoms is not uniform and is slightly displaced towards the more electronegative
Electronegativity

Electronegativity, symbol χ, is a chemical property that describes the ability of an atom to attract electrons towards itself in a covalent bond....
 of the two atoms. This causes a permanent state of bond polarization
Polar bond

Polar bond may refer to:Polar bond* Chemical polarity* Covalent bond* Bond dipole moment* Partial charge* Dipoles#Molecular dipoles* Electronegativity...
, where the more electronegative atom has a slight negative charge(d-) and the other atom has a slight positive charge(d+).

If the electronegative atom is then joined to a chain of atoms, usually carbon
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....
, the positive charge is relayed to the other atoms in the chain. This is the electron-withdrawing inductive effect, also known as the -I effect.

Some groups, such as the alkyl group are less electron-withdrawing than hydrogen
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....
 and are therefore considered as electron-releasing. This is electron releasing character is indicated by the +I effect.

As the induced change in polarity is less than the original polarity, the inductive effect rapidly dies out, and is significant only over a short distance. The inductive effect is permanent but feeble, as it involves the shift of strongly held s-bond electrons, and other stronger factors may overshadow this effect.

The inductive effect may be caused by some molecules also. Relative inductive effects have been experimentally measured with reference to hydrogen.

Inductive Effect
Inductive effects can be measured through the Hammett equation
Hammett equation

The Hammett equation in organic chemistry describes a linear free-energy relationship relating reaction rates and equilibrium constants for many reactions involving benzoic acid derivatives with meta- and para-substituents to each other with just two parameters: a substituent constant and a reaction constant....
.

Applications

  • Aliphatic carboxylic acids. The strength of a carboxylic acid
    Carboxylic acid

    Carboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the Chemical formula -COH, usually written -COOH or -CO2H....
     depends on the extent of its ionization
    Ionization

    Ionization is the physics process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or other ions....
    -the more the ionization, the stronger is the acid. The strength of an acid is denoted by the numerical value of pKa
    Acid dissociation constant

    An acid dissociation constant, Ka, is a quantitative measure of the strong acid in solution. It is the equilibrium constant for a chemical reaction known as Dissociation in the context of acid-base reactions....
    . In aliphatic acids, the electron releasing inductive effect of the methyl group, increases the electron density on oxygen
    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]]...
     and thus hinders the breaking of the O-H bond, which consequently reduces the ionization. Greater ionization in formic acid
    Formic acid

    Formic acid is the simplest carboxylic acid. Its formula is hydrogencarbonoxygenOH or CH2O2. It is an important intermediate in chemical synthesis and occurs naturally, most notably in the venom of bee and ant stingers....
     when compared to acetic acid
    Acetic acid

    Acetic acid, CH3COOH, also known as ethanoic acid, is an organic acid which gives vinegar its sour taste and pungent smell. Pure, water-free acetic acid is a colourless liquid that absorbs water from the environment , and freezes at 16.7 Celsius to a colourless crystalline solid....
     makes formic acid(pKa=3.75) stronger than acetic acid(pKa=4.76). Monochloroacetic acid(pKa=2.82) is stronger than formic acid since the electron-withdrawing effect of chlorine promotes ionization.
  • Aromatic carboxylic acids. In benzoic acid
    Benzoic acid

    Benzoic acid, C7H6O2 , is a colorless crystalline solid and the simplest aromatic carboxylic acid. The name derived from gum benzoin, which was for a long time the only source for benzoic acid....
    , the carbon atoms which are present in the ring are sp2 hybridised
    Orbital hybridisation

    In chemistry, hybridisation or hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals suitable for the qualitative description of atomic bonding properties....
    .As a result, benzoic acid(pKa=4.20) is a stronger acid than cyclohexane
    Cyclohexane

    Cyclohexane is a cycloalkane with the molecular formula Carbon6Hydrogen12. Cyclohexane is used as a nonpolar solvent for the chemical industry, and also as a raw material for the industrial production of adipic acid and caprolactam, both of which are intermediates used in the production of nylon....
     carboxylic acid
    Carboxylic acid

    Carboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the Chemical formula -COH, usually written -COOH or -CO2H....
    (pKa=4.87). Also, electron-withdrawing groups substituted at the ortho and para positions, enhance the acid strength.
  • Dioic acids. Since the carboxyl group is itself an electron-withdrawing group, the dioic acids are, in general, stronger than their monocarboxyl analogues.
  • In the so-called Baker-Nathan effect
    Baker-Nathan effect

    The Baker-Nathan effect in organic chemistry is an effect observed with reaction rates for certain chemical reactions with certain substrates where the order in reactivity cannot be explained solely by an inductive effect of substituents....
     the observed order in electron-releasing alkyl substituents is apparently reversed.


See also

  • Important publications in organic chemistry
    List of publications in chemistry

    This is a list of important publications in chemistry, organized by field.Some reasons why a particular publication might be regarded as important:...