Molecular attraction occurs when neutrally-charged molecules nevertheless experience the uneven distribution of electrons over their structure due to London Forces induced by random variations of electron density occurring in non-polar compounds, hydrogen bonding due to the production of what is essentially a bare proton when it is bonded with a strongly electronegative element such as fluorine

Fluorine

Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...

, oxygen

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 or nitrogen

Nitrogen

Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

, and the dipole-dipole interaction between compounds that are polar, such as salt

Salt

In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

. The properties of liquids and the expansion of water ice when it freezes are due to molecular attraction.

Source

Dr. Walt Volland, Intermolecular Forces