van der Waals forces

Pronunciation: von der vahls

Definition: first postulated by van der Waals in 1873 to explain deviations from ideal gas behavior seen in real gases; the attractive forces between atoms or molecules other than electrostatic (ionic), covalent (sharing of electrons), or hydrogen bonding (sharing a proton); generally ascribed to dipolar and dispersion effects, π-electrons, and the like; these relatively nondescript forces contribute to the mutual attraction of organic molecules.

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