Carbon tetrachloride, \(\mathrm{CCl}_{4},\) is nonpolar. What forces hold the molecules together?

Nonpolar molecules, such as carbon tetrachloride (\r\(\r\text{CCl}_{4}\r\)), play a significant role in chemistry due to their unique properties. These molecules are characterized by an even distribution of electrons across the molecule, which leads to the absence of permanent charge imbalances. Consequently, they do not have distinct positive or negative poles.

\rNonpolar molecules are typically hydrophobic, meaning they do not mix well with polar substances like water. This characteristic is key in applications ranging from industrial solvents to biological cell membranes. Understanding their behavior is crucial in many chemical processes, such as the dissolution of substances and the formation of structures like lipid bilayers.

London dispersion forces, also referred to as 'dispersion forces' or 'induced dipole-induced dipole attractions,' are a type of force that can act between nonpolar molecules such as \(\text{CCl}_{4}\). Despite their lack of permanent dipoles, these molecules can still exhibit attractive forces due to momentary fluctuations in electron density.

\rThis temporary imbalance can induce a similar imbalance in adjacent molecules, leading to a weak, nonpermanent attraction. These forces are the weakest of all intermolecular forces, yet they are universal, affecting all atoms and molecules. The strength of London dispersion forces increases with greater molecular mass and a larger contact area between molecules.

Van der Waals forces encompass various intermolecular forces, including London dispersion forces, dipole-dipole interactions, and hydrogen bonds. These forces are responsible for the collective behavior of molecules, influencing the phase of matter, melting points, boiling points, and solubility.

\rLondon dispersion forces are a subset of van der Waals forces but are often discussed independently because they are the only type of van der Waals force present in nonpolar molecules like \(\text{CCl}_{4}\). Recognizing van der Waals forces can provide insights into molecular interactions and properties such as why nonpolar gases can be liquefied at lower temperatures.