What are the two types of dipole?

There are two main types of electric dipoles: Permanent dipoles and Temporary dipoles.

Permanent dipole

A permanent dipole is a fixed charge separation in a molecule. That is, the positive and negative charges remain in the same relative position within the molecule. This type of dipole is common in molecules where the atoms are arranged asymmetrically and the electrons are not evenly distributed.

Examples of molecules with permanent dipoles include water (H2O), ammonia (NH3), and carbon dioxide (CO2). These molecules are polar due to the charge separation between the atoms and can form dipole-dipole interactions with other polar molecules.

Temporary dipole

A temporary dipole is an intramolecular charge separation that is not fixed but fluctuates due to the movement of electrons within the molecule. This type of dipole is common in non-polar molecules with uniformly distributed electron distributions and no permanent charge separation.

An example of a molecule with a temporary dipole is an alkane, a hydrocarbon with only single bonds between carbon atoms. These molecules are non-polar and have no permanent charge separation, but electrons can move and form temporary dipoles. These temporary dipoles are the weakest type of intermolecular force and give rise to the London dispersion forces present in all molecules.

In summary, there are two main types of electric dipoles. The permanent dipole is the fixed charge separation in the molecule, and the temporary dipole is the fluctuating charge separation due to the movement of electrons in the molecule.

Let me know if you have more questions or if there is a specific topic that you would like to know more about.