Dispersion force, also known as London force, is a type of intermolecular force that occurs between atoms or molecules. The spelling of the word "dispersion" reflects the IPA phonetic transcription, which includes the following sounds: /dɪˈspɜː.ʒən/ or /dɪˈspɜːr.ʒən/. The word is pronounced with a stress on the second syllable, and the "s" sound in the first syllable is followed by a "p" sound. This force is caused by temporary fluctuations in electron density and contributes to the attractive forces between molecules.
Dispersion force, also known as London dispersion force or van der Waals force, refers to a type of intermolecular force or attractive force between molecules. It is considered the weakest force among the intermolecular forces and is responsible for many physical properties of substances, such as boiling points, melting points, and viscosity.
Dispersion forces arise due to the temporary fluctuations or variations in electron distribution within a molecule. Electrons are constantly in motion and at any given time, they may be more concentrated on one side of a molecule, creating a temporary dipole or a temporary imbalance in electron distribution. These temporary dipoles induce dipoles in neighboring molecules, resulting in an attractive force between them.
The strength of dispersion forces depends on the size and shape of the molecules involved. Larger, more polarizable molecules tend to exhibit stronger dispersion forces because they have a larger number of electrons and a greater surface area for interactions.
Dispersion forces are present in all molecules and atoms, regardless of their polarity. However, their significance becomes more apparent in nonpolar molecules, where they are the dominant intermolecular force.
Understanding dispersion forces is crucial in various scientific fields, including chemistry, biology, and materials science. These forces play a key role in determining how substances interact, mix, and behave in various conditions.
The etymology of the term "dispersion force" can be understood by analyzing the meanings of its component words.
1. Dispersion: word "dispersion" comes from the Latin word "dispersus", which means "scattered" or "spread out". In the context of chemistry, dispersion refers to the scattering or spreading out of particles or molecules.
2. Force: word "force" has its origins in the Latin word "fortis", which means "strong". It generally refers to a physical power or influence that can cause an object to move, change direction, or be deformed.
When combined, the term "dispersion force" is used to describe the intermolecular forces or interactions between molecules caused by temporary fluctuations in charge distribution within the molecules.se forces are also known as London dispersion forces after Fritz London, who first described them in 1930 based on the quantum mechanical theory of electron distribution.