What is the difference between a dipole and polarity?

[marc32123]

From what I have been learning recently, a dipole is a separation of electric charges and in chemistry, a dipole refers to the separation of charges within a molecule between two covalently bonded atoms (which is caused from one atom having a higher electronegativity) What I don't understand is how this is different from polarization in chemistry?

 

[DrDu]

A dipole is defined more strictly via a multipole expansion of the charge contribution, see
http://en.wikipedia.org/wiki/Multipole_expansion
Polarisation referseither to a change of the dipole moment due to an external field or to the sources of the electric field inside the medium. In simple situations, the latter can be interpreted as the macroscopic dipole moment density.

 

[marc32123]

Thanks for the info, although it is kind of out of the realm of what I understand about chem so far. I checked out that article on wiki already and had no idea what it was saying. I am terrible with math. Is there any way you could somewhat explain it in a somewhat understandable way what you mean by

A dipole is defined more strictly via a multipole expansion of the charge contribution

It would be greatly appreciated!