Question

What are molecular dipoles?

Answer 1

Molecular dipoles exist if one or more of the atoms is more electronegative than the other(s)

Explanation:

The most common dipole is water.

Since `O` is more electronegative than `H` the shared electrons tend to be more in the neighbourhood of the `O`-atom.
Since the molecule is 'bent' they tend to be more in the upper part of the figure above. This gives a slight negative charge (called `delta-`) at the top, and a `delta+` at the `H`-arms.

Since `+` and `-` attract, the next molecule will tend to turn one of its `H` 's toward the `O` of the first one.

This polarity also has many consequences for the behaviour of a polar liquid like boiling point, solvability, etc. and even the shape of snow flakes.