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In hydrocarbons and waxes, the dispersion forces are sufficient to cause condensation from the gas phase into the liquid or solid phase. Sublimation heats of e.g. hydrocarbon crystals reflect the dispersion interaction. Liquification of oxygen and nitrogen gases into liquid phases is also dominated by attractive London dispersion forces.
Dispersion forces keep the molecule inert even while its core Si-Si bond lengthens. Similarly, the longest known Ge-Ge bond is found in t Bu 3 GeGe t Bu 3 and is also facilitated by dispersion stabilization. [19] Dispersion stabilization has also been invoked for (t BuC) 3 P, a main group analog of a hydrocarbon tetrahedrane. [20]
The strength of London dispersion forces is proportional to the polarizability of the molecule, which in turn depends on the total number of electrons and the area over which they are spread. Hydrocarbons display small dispersive contributions, the presence of heteroatoms lead to increased LD forces as function of their polarizability, e.g. in ...
In absence of solvents hydrocarbons such as hexane form crystals due to dispersive forces ; the sublimation heat of crystals is a measure of the dispersive interaction. While these interactions are short-lived and very weak, they can be responsible for why certain non-polar molecules are liquids at room temperature.
The source of adhesive forces, according to the dispersive adhesion mechanism, is the weak interactions that occur between molecules close together. [2] These interactions include London dispersion forces, Keesom forces, Debye forces and hydrogen bonds. Individually, these attractions are not very strong, but when summed over the bulk of a ...
In condensed matter physics and physical chemistry, the Lifshitz theory of van der Waals forces, sometimes called the macroscopic theory of van der Waals forces, is a method proposed by Evgeny Mikhailovich Lifshitz in 1954 for treating van der Waals forces between bodies which does not assume pairwise additivity of the individual intermolecular forces; that is to say, the theory takes into ...
Lipophilicity, hydrophobicity, and non-polarity may describe the same tendency towards participation in the London dispersion force, as the terms are often used interchangeably. However, the terms "lipophilic" and " hydrophobic " are not synonymous, as can be seen with silicones and fluorocarbons , which are hydrophobic but not lipophilic.
Keesom forces are the forces between the permanent dipoles of two polar molecules. [ 23 ] : 701 London dispersion forces are the forces between induced dipoles of different molecules. [ 23 ] : 703 There can also be an interaction between a permanent dipole in one molecule and an induced dipole in another molecule.