Question #dbcca

The simple case of an electric dipole is when a positive charge and a negative charge separated by a distance #r# .

The electric dipole moment #vec mu or vec p#, is the product of the electric charge q and the distance #d# separating the two charges:
#vec mu = q*vec r#

#mu# is the dipole moment vector
#q# is the magnitude of the charge, and
#vec r# is the vector representing distance between the charges

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When you have many charges, a dipole is a separation of the positive charges from the negative ones, you'll have two poles.

Here's an example :
The Oxygen is more electronegative so it'll pull the electrons toward it self, the electrons are negatively charged so you'll have a negative charge around the Oxygen #(-)# and the Hydrogen will have a small electron density around it #(+)# which forms an electric dipole.

The overall electric dipole moment is the vector addition of all the electric dipole moments :

![http://www.chemtube3d.com/spectrorotcd0-CE-TEST-ROTATE-ALL.html]()

another example :

![http://www.chemtube3d.com/spectrorotcd0-CE-TEST-ROTATE-ALL.html]()

Sources:
https://en.wikipedia.org/wiki/Electric_dipole_moment
https://en.wikipedia.org/wiki/Dipole
http://chemwiki.ucdavis.edu/Core/Physical_Chemistry/Atomic_Theory/Dipole_Moments