Attractive intermolecular forces consist of four types:
(i) `text(Dipole-dipole forces)` : Dipole- dipole interactions are electrostatic interactions of permanent dipoles in molecules. These interactions tend to align the molecules to increase the attraction (reducing potential energy). An example of a dipole- dipole interaction can be seen in hydrogen chloride (`HCl`). The positive end of a polar molecule will attract the negative end of the other molecule and cause them to be arranged in a specific arrangement. Polar molecules have a net attraction between them. For example `HCl` and chloroform (`CHCl_3`).
(ii) `text(lon-dipole forces)` : Ion-dipole and induced-dipole forces operate much like dipole-dipole and induced-dipole interactions. However, instead of only polar and non-polar molecules being involved, ion interactions involve ions (as the name suggests). Ion-dipole and ion-induced dipole forces are stronger than dipole interactions because the charge of any ion is much greater than the charge of a dipole moment. Ion-dipole is greater than Hydrogen bonding.
An ion-dipole force consists of an ion and a polar molecule interacting. They align so that the positive and negative forces are next to one another, allowing for maximum attraction.An ion-induced dipole force consists of an ion and a non-polar molecule interacting. Like a dipole-induced dipole force, the charge of the ion causes a distortion of the electron cloud on the non-polar molecule.
(iii) `text(Dipole-induced dipole force or Debye forces)` : The induced dipole forces appear from the induction (also known as polarization), which is the attractive interaction between a permanent multipole on one molecule with an induced (by the former di/multipole) multipole on another molecule. This interaction is called Debye force after Peter J.W. Debye.
The example of an induction-interaction between permanent dipole and induced dipole is `HCl` and `Ar`. In this system, `Ar` experiences a dipole as its electrons are attracted (to `H` side) or repelled (from `Cl` side) by `HCl`. This kind of interaction can be expected between any polar molecule and nonpolar/symmetrical molecule. The induction interaction force is far weaker than dipole-dipole interaction, but stronger than the London dispersion force.
(iv) `text(Instantaneous dipole-induced dipole forces or London dispersion forces)` : Otherwise known as quantum-induced instantaneous polarization or instantaneous dipole-induced dipole forces, the London dispersion force is caused by correlated movements of the electrons in interacting molecules. The electrons, which belong to different molecules, start "fleeing" and avoiding each other at the short intermolecular distances, which is frequently described as formation of "instantaneous dipoles" that attract each other.
Attractive intermolecular forces consist of four types:
(i) `text(Dipole-dipole forces)` : Dipole- dipole interactions are electrostatic interactions of permanent dipoles in molecules. These interactions tend to align the molecules to increase the attraction (reducing potential energy). An example of a dipole- dipole interaction can be seen in hydrogen chloride (`HCl`). The positive end of a polar molecule will attract the negative end of the other molecule and cause them to be arranged in a specific arrangement. Polar molecules have a net attraction between them. For example `HCl` and chloroform (`CHCl_3`).
(ii) `text(lon-dipole forces)` : Ion-dipole and induced-dipole forces operate much like dipole-dipole and induced-dipole interactions. However, instead of only polar and non-polar molecules being involved, ion interactions involve ions (as the name suggests). Ion-dipole and ion-induced dipole forces are stronger than dipole interactions because the charge of any ion is much greater than the charge of a dipole moment. Ion-dipole is greater than Hydrogen bonding.
An ion-dipole force consists of an ion and a polar molecule interacting. They align so that the positive and negative forces are next to one another, allowing for maximum attraction.An ion-induced dipole force consists of an ion and a non-polar molecule interacting. Like a dipole-induced dipole force, the charge of the ion causes a distortion of the electron cloud on the non-polar molecule.
(iii) `text(Dipole-induced dipole force or Debye forces)` : The induced dipole forces appear from the induction (also known as polarization), which is the attractive interaction between a permanent multipole on one molecule with an induced (by the former di/multipole) multipole on another molecule. This interaction is called Debye force after Peter J.W. Debye.
The example of an induction-interaction between permanent dipole and induced dipole is `HCl` and `Ar`. In this system, `Ar` experiences a dipole as its electrons are attracted (to `H` side) or repelled (from `Cl` side) by `HCl`. This kind of interaction can be expected between any polar molecule and nonpolar/symmetrical molecule. The induction interaction force is far weaker than dipole-dipole interaction, but stronger than the London dispersion force.
(iv) `text(Instantaneous dipole-induced dipole forces or London dispersion forces)` : Otherwise known as quantum-induced instantaneous polarization or instantaneous dipole-induced dipole forces, the London dispersion force is caused by correlated movements of the electrons in interacting molecules. The electrons, which belong to different molecules, start "fleeing" and avoiding each other at the short intermolecular distances, which is frequently described as formation of "instantaneous dipoles" that attract each other.